org.perro.functions.predicate

Class DblPredicateUtils

java.lang.Object

org.perro.functions.predicate.DblPredicateUtils

public final class DblPredicateUtils
extends java.lang.Object

Methods that build predicates specifically those involving primitive double types.

Method Summary

Modifier and Type	Method and Description
static java.util.function.DoublePredicate	dblConstant(boolean b) Builds a double predicate based on a passed constant boolean value.
static java.util.function.DoublePredicate	dblGt(double compareTo) Builds a DoublePredicate that determines whether a value is greater than a passed constant double value.
static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate	dblGt(java.util.function.DoubleFunction<? extends R> function, R compareTo) Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is greater than a passed constant value of type <R> (also a Comparable).
static java.util.function.DoublePredicate	dblGte(double compareTo) Builds a DoublePredicate that determines whether a value is greater than or equal to a passed constant double value.
static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate	dblGte(java.util.function.DoubleFunction<? extends R> function, R compareTo) Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is greater than or equal to a passed constant value of type <R> (also a Comparable).
static java.util.function.DoublePredicate	dblIsNotNull(java.util.function.DoubleFunction<?> function) Given a DoubleFunction that returns a value of an arbitrary type, this method builds a DoublePredicate that determines whether that returned value is not null.
static java.util.function.DoublePredicate	dblIsNull(java.util.function.DoubleFunction<?> function) Given a DoubleFunction that returns a value of an arbitrary type, this method builds a DoublePredicate that determines whether that returned value is null.
static java.util.function.DoublePredicate	dblLt(double compareTo) Builds a DoublePredicate that determines whether a value is less than a passed constant double value.
static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate	dblLt(java.util.function.DoubleFunction<? extends R> function, R compareTo) Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is less than a passed constant value of type <R> (also a Comparable).
static java.util.function.DoublePredicate	dblLte(double compareTo) Builds a DoublePredicate that determines whether a value is less than or equal to a passed constant double value.
static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate	dblLte(java.util.function.DoubleFunction<? extends R> function, R compareTo) Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is less than or equal to a passed constant value of type <R> (also a Comparable).
static <T> java.util.function.DoublePredicate	dblMapAndFilter(java.util.function.DoubleFunction<? extends T> function, java.util.function.Predicate<? super T> predicate) Given a DoubleFunction that returns a value of type <T>, and a Predicate, this method builds a DoublePredicate that applies the return value of the DoubleFunction to the given predicate.
static java.util.function.DoublePredicate	dblNot(java.util.function.DoublePredicate predicate) A DoublePredicate that simply negates the passed DoublePredicate.
static <U> java.util.function.DoublePredicate	dblPredicate(java.util.function.BiPredicate<java.lang.Double,? super U> biPredicate, U value) Builds a DoublePredicate from a passed BiPredicate<Double, U>, which can be very useful in the common situation where you are streaming through a collection of elements, and have a double predicate method to call that takes two parameters - the first one being the double element on which you are streaming, and the second being some constant value that will be passed to all invocations.
static java.util.function.DoublePredicate	dblPredicate(java.util.function.DoublePredicate predicate) Simply casts a method reference, which takes a single parameter of type double or Double, and returns a boolean or Boolean, to a DoublePredicate.
static <R> java.util.function.DoublePredicate	dblToObjContains(java.util.Collection<? extends R> collection, java.util.function.DoubleFunction<? extends R> function) Given a Collection whose elements are of type <R>, and a DoubleFunction that returns a value of type <R>, this method builds a DoublePredicate that determines if the given collection contains the value returned by the double function.
static <R> java.util.function.DoublePredicate	dblToObjsAllMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function, java.util.function.Predicate<R> predicate) Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether all elements in the returned Collection match the Predicate.
static <R> java.util.function.DoublePredicate	dblToObjsAnyMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function, java.util.function.Predicate<R> predicate) Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether any of the elements in the returned Collection match the Predicate.
static <R> java.util.function.DoublePredicate	dblToObjsNoneMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function, java.util.function.Predicate<R> predicate) Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether none of the elements in the returned Collection match the Predicate.
static org.perro.functions.predicate.DoubleWithDelta	dblWithDelta(double value, double delta) Combines a double value for use in a comparison, with a delta.
static <U> java.util.function.DoublePredicate	inverseDblPredicate(java.util.function.BiPredicate<? super U,java.lang.Double> biPredicate, U value) Builds a DoublePredicate from a passed BiPredicate<Double, U>, which can be very useful in the common situation where you are streaming through a collection of elements, and have a double predicate method to call that takes two parameters.
static <R> java.util.function.DoublePredicate	inverseDblToObjContains(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function, R value) Given a DoubleFunction that returns a Collection<R>, this method builds a DoublePredicate that determines if the collection returned by that double function contains the passed value of type <R>.
static <T> java.util.function.Predicate<T>	inverseObjToDblContains(java.util.function.Function<T,double[]> function, double value) Given a Function that takes an element of type <T> and returns an array of doubles, this method builds a Predicate that determines if the array returned by that function contains the passed constant double value.
static <T> java.util.function.Predicate<T>	isDblArrayEmpty(java.util.function.Function<? super T,double[]> function) Given a Function that returns an array of doubles, this method builds a Predicate that determines whether the returned array is empty.
static <T> java.util.function.Predicate<T>	isDblArrayNotEmpty(java.util.function.Function<? super T,double[]> function) Given a Function that returns an array of doubles, this method builds a Predicate that determines whether the returned array is not empty.
static java.util.function.DoublePredicate	isDblCollEmpty(java.util.function.DoubleFunction<? extends java.util.Collection<?>> function) Given a DoubleFunction that returns a Collection of elements of an arbitrary type, this method builds a DoublePredicate that determines whether the returned Collection is empty.
static java.util.function.DoublePredicate	isDblCollNotEmpty(java.util.function.DoubleFunction<? extends java.util.Collection<?>> function) Given a DoubleFunction that returns a Collection of elements of an arbitrary type, this method builds a DoublePredicate that determines whether the returned Collection is not empty.
static java.util.function.DoublePredicate	isDblEqual(double value) This method builds a DoublePredicate whose parameter is to be compared for equality to the passed double constant value.
static java.util.function.DoublePredicate	isDblEqual(double value, double delta) This method builds a DoublePredicate whose parameter is to be compared for equality to the passed double constant value.
static java.util.function.DoublePredicate	isDblEqual(java.util.function.DoubleUnaryOperator operator, double value) Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if the value returned by that operator is equal to the passed constant double value.
static java.util.function.DoublePredicate	isDblEqual(java.util.function.DoubleUnaryOperator operator, org.perro.functions.predicate.DoubleWithDelta doubleWithDelta) Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if a value returned by that operator is equal to a constant double value, within a delta parameter.
static java.util.function.DoublePredicate	isDblNotEqual(double value) This method builds a DoublePredicate whose parameter is to be compared for inequality to the passed double constant value.
static java.util.function.DoublePredicate	isDblNotEqual(double value, double delta) This method builds a DoublePredicate whose parameter is to be compared for inequality to the passed double constant value.
static java.util.function.DoublePredicate	isDblNotEqual(java.util.function.DoubleUnaryOperator operator, double value) Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if the value returned by that operator is not equal to the passed constant double value.
static java.util.function.DoublePredicate	isDblNotEqual(java.util.function.DoubleUnaryOperator operator, org.perro.functions.predicate.DoubleWithDelta doubleWithDelta) Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if a value returned by that operator is equal to a constant double value, within a delta parameter.
static <T> java.util.function.Predicate<T>	mapToDblAndFilter(java.util.function.ToDoubleFunction<? super T> function, java.util.function.DoublePredicate predicate) Given a ToDoubleFunction taking a value of type <T>, and a DoublePredicate, this method builds a Predicate that takes an element of type <T>, and applies the return value of the ToDoubleFunction to the given predicate.
static <T> java.util.function.Predicate<T>	objToDblContains(double[] doubles, java.util.function.ToDoubleFunction<? super T> function) Given a double array, and a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that determines if the given array contains the value returned by the ToDoubleFunction.
static <T> java.util.function.Predicate<T>	objToDblsAllMatch(java.util.function.Function<T,? extends double[]> function, java.util.function.DoublePredicate predicate) Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether all doubles in the returned array match the DoublePredicate.
static <T> java.util.function.Predicate<T>	objToDblsAnyMatch(java.util.function.Function<T,? extends double[]> function, java.util.function.DoublePredicate predicate) Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether any of the doubles in the returned array match the DoublePredicate.
static <T> java.util.function.Predicate<T>	objToDblsNoneMatch(java.util.function.Function<T,? extends double[]> function, java.util.function.DoublePredicate predicate) Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether none of the doubles in the returned array match the DoublePredicate.
static <T> java.util.function.Predicate<T>	toDblGt(java.util.function.ToDoubleFunction<? super T> function, double compareTo) Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is greater than a passed constant double value.
static <T> java.util.function.Predicate<T>	toDblGte(java.util.function.ToDoubleFunction<? super T> function, double compareTo) Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is greater than or equal to a passed constant double value.
static <T> java.util.function.Predicate<T>	toDblLt(java.util.function.ToDoubleFunction<? super T> function, double compareTo) Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is less than a passed constant double value.
static <T> java.util.function.Predicate<T>	toDblLte(java.util.function.ToDoubleFunction<? super T> function, double compareTo) Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is less than or equal to a passed constant double value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

dblPredicate

public static java.util.function.DoublePredicate dblPredicate(java.util.function.DoublePredicate predicate)

Simply casts a method reference, which takes a single parameter of type double or Double, and returns a boolean or Boolean, to a DoublePredicate. This could be useful in a situation where methods of the DoublePredicate functional interface are to be called on a method reference. For example:

     private double[] getDoublesInRange(double[] doubles) {
         return Arrays.stream(doubles)
             .filter(DblPredicateUtils.dblPredicate(this::isGreaterThanOrEqualToMin)
                 .and(this::isLessThanOrEqualToMax))
             .toArray();
     }

     private boolean isGreaterThanOrEqualToMin(double target) {
         ...
     }

     private boolean isLessThanOrEqualToMax(double target) {
         ...
     }
 

The DoublePredicate.and(...) method can only be called on the method reference because of the cast. Note that the second predicate does not need to be cast, because DoublePredicate.and(...) already takes a DoublePredicate just like this method, and so is already doing a cast.

Parameters:

predicate - A method reference to be cast to a DoublePredicate.

Returns:

A method reference cast to a DoublePredicate.

dblPredicate

public static <U> java.util.function.DoublePredicate dblPredicate(java.util.function.BiPredicate<java.lang.Double,? super U> biPredicate,
                                                                  U value)

Builds a DoublePredicate from a passed BiPredicate<Double, U>, which can be very useful in the common situation where you are streaming through a collection of elements, and have a double predicate method to call that takes two parameters - the first one being the double element on which you are streaming, and the second being some constant value that will be passed to all invocations. This would typically be called from within a chain of method calls based on a DoubleStream. In the following example, assume the Stock objects passed to the getHighestPriceOfStockBelowLimit(...) method are to be filtered based on whether their price is less than a limit for the passed Client:

     private double[] getHighestPriceOfStockBelowLimit(Collection<Stock> stocks, Client client) {
         return stocks.stream()
             .mapToDouble(Stock::getPrice)
             .filter(DblPredicateUtils.dblPredicate(this::isPriceBelowLimit, client))
             .max()
             .orElse(-1.0D);
     }

     private boolean isPriceBelowLimit(double price, Client client) {
         ...
     }
 

Or, with static imports:

     return stocks.stream()
         .mapToDouble(Stock::getPrice)
         .filter(dblPredicate(this::isPriceBelowLimit, client))
         .max()
         .orElse(-1.0D);
 

Type Parameters:

U - The type of the constant value to be passed as the second parameter to each invocation of biPredicate.

Parameters:

biPredicate - A method reference (a BiPredicate) which takes two parameters - the first of type Double, and the second of type <U>. The method reference will be converted by this method to a DoublePredicate. Behind the scenes, this BiPredicate will be called, passing the constant value to each invocation as the second parameter.

value - A constant value, in that it will be passed to every invocation of the passed biPredicate as the second parameter to it, and will have the same value for each of them.

Returns:

A DoublePredicate adapted from the passed BiPredicate.

inverseDblPredicate

public static <U> java.util.function.DoublePredicate inverseDblPredicate(java.util.function.BiPredicate<? super U,java.lang.Double> biPredicate,
                                                                         U value)

Builds a DoublePredicate from a passed BiPredicate<Double, U>, which can be very useful in the common situation where you are streaming through a collection of elements, and have a double predicate method to call that takes two parameters. In the BiPredicate passed to this method, the parameters are basically the same as in the call to dblPredicate(BiPredicate, Object), but in the inverse order. Here, the first parameter is a constant value that will be passed to all invocations of the method, and the second parameter is the target double element on which you are streaming. This would typically be called from within a chain of method calls based on a DoubleStream. In the following example, assume the Stock objects passed to the getHighestPriceOfStockBelowLimit(...) method are to be filtered based on whether their price is less than a limit for the passed Client:

     private double[] getHighestPriceOfStockBelowLimit(Collection<Stock> stocks, Client client) {
         return stocks.stream()
             .mapToDouble(Stock::getPrice)
             .filter(DblPredicateUtils.inverseDblPredicate(this::isPriceBelowLimit, client))
             .max()
             .orElse(-1.0D);
     }

     private boolean isPriceBelowLimit(Client client, double price) {
         ...
     }
 

Or, with static imports:

     return stocks.stream()
         .mapToDouble(Stock::getPrice)
         .filter(inverseDblPredicate(this::isPriceBelowLimit, client))
         .max()
         .orElse(-1.0D);
 

Type Parameters:

U - The type of the constant value to be passed as the first parameter to each invocation of biPredicate.

Parameters:

biPredicate - A method reference (a BiPredicate) which takes two parameters - the first of type <U>, and the second of type Double. The method reference will be converted by this method to a DoublePredicate. Behind the scenes, this BiPredicate will be called, passing the constant value to each invocation as the first parameter.

value - A constant value, in that it will be passed to every invocation of the passed biPredicate as the first parameter to it, and will have the same value for each of them.

Returns:

A DoublePredicate adapted from the passed BiPredicate.

dblConstant

public static java.util.function.DoublePredicate dblConstant(boolean b)

Builds a double predicate based on a passed constant boolean value. The target element of type double that is passed to the predicate is ignored, and the constant value is simply returned. This comes in handy when combining one predicate with another using Predicate.and(...) or Predicate.or(...). Consider the following example:

     private double[] getHighestPriceOfStockBelowLimit(Collection<Stock> stocks, Client client) {
         boolean hasLimit = client.getLimit() > 0.0D;
         return stocks.stream()
             .mapToDouble(Stock::getPrice)
             .filter(DblPredicateUtils.dblNot(DblPredicateUtils.dblConstant(hasLimit))
                 .or(DblPredicateUtils.dblPredicate(this::isPriceBelowLimit, client))
             .max()
             .orElse(-1.0D);
     }

     private boolean isPriceBelowLimit(double price, Client client) {
         ...
     }
 

Or, with static imports:

     return stocks.stream()
         .mapToDouble(Stock::getPrice)
         .filter(dblNot(dblConstant(hasLimit))
             .or(dblPredicate(this::isPriceBelowLimit, client))
         .max()
         .orElse(-1.0D);
 

Parameters:

b - A constant boolean value that will be the result of every invocation of the returned DoublePredicate.

Returns:

A DoublePredicate returning a constant boolean value.

dblNot

public static java.util.function.DoublePredicate dblNot(java.util.function.DoublePredicate predicate)

A DoublePredicate that simply negates the passed DoublePredicate. A predicate can always be negated via predicate.negate(), however using this method may improve readability.

Parameters:

predicate - A DoublePredicate whose result is to be negated.

Returns:

A negated DoublePredicate.

isDblEqual

public static java.util.function.DoublePredicate isDblEqual(double value)

This method builds a DoublePredicate whose parameter is to be compared for equality to the passed double constant value.

Parameters:

value - A constant value to be compared to the parameter of the DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its parameter to a constant double value for equality.

isDblEqual

public static java.util.function.DoublePredicate isDblEqual(double value,
                                                            double delta)

This method builds a DoublePredicate whose parameter is to be compared for equality to the passed double constant value. If the absolute value of the difference between the two numbers is less than or equal to a passed delta, the values will be considered equal.

Parameters:

value - A constant value to be compared to the parameter of the DoublePredicate built by this method.

delta - A delta value meaning that if the absolute value of the difference between the two numbers to be compared is less than or equal to the delta, the values will be considered equal.

Returns:

A DoublePredicate that compares its parameter to a constant double value for equality within a delta value.

isDblEqual

public static java.util.function.DoublePredicate isDblEqual(java.util.function.DoubleUnaryOperator operator,
                                                            double value)

Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if the value returned by that operator is equal to the passed constant double value. For example:

     double[] doubles = IntStream.range(1, 10).asDoubleStream().toArray();
     double[] evens = Arrays.stream(doubles)
             .filter(DblPredicateUtils.isDblEqual(DblMapperUtils.dblModulo(2.0D), 0.0D))
             .toArray();
 

Or, with static imports:

     double[] evens = Arrays.stream(doubles)
             .filter(isDblEqual(dblModulo(2.0D), 0.0D))
             .toArray();
 

Parameters:

operator - A DoubleUnaryOperator whose return value is to be compared with a passed constant double value for equality.

value - A value to be compared to the result of the passed operator for equality.

Returns:

A DoublePredicate whose return value is compared for equality to a passed constant double value.

isDblEqual

public static java.util.function.DoublePredicate isDblEqual(java.util.function.DoubleUnaryOperator operator,
                                                            org.perro.functions.predicate.DoubleWithDelta doubleWithDelta)

Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if a value returned by that operator is equal to a constant double value, within a delta parameter.

     double[] doubles = IntStream.range(1, 10).asDoubleStream().toArray();
     double[] evens = Arrays.stream(doubles)
             .filter(DblPredicateUtils.isDblEqual(DblMapperUtils.dblModulo(2.0D), DblPredicateUtils.dblWithDelta(0.0D, 0.000001D)))
             .toArray();
 

Or, with static imports:

     double[] evens = Arrays.stream(doubles)
             .filter(isDblEqual(dblModulo(2.0D), dblWithDelta(0.0D, 0.000001D)))
             .toArray();
 

Parameters:

operator - A DoubleUnaryOperator whose return value is to be compared with a passed constant double value for equality.

doubleWithDelta - An object containing a constant double value for comparison, and a double delta.

Returns:

A DoublePredicate whose parameter is to be applied to the passed operator, and the result is compared for equality to a constant double value. If the difference is less than or equal to a delta value, then the values are considered equal.

isDblNotEqual

public static java.util.function.DoublePredicate isDblNotEqual(double value)

This method builds a DoublePredicate whose parameter is to be compared for inequality to the passed double constant value.

Parameters:

value - A constant value to be compared to the parameter of the DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its parameter to a constant double value for inequality.

isDblNotEqual

public static java.util.function.DoublePredicate isDblNotEqual(double value,
                                                               double delta)

This method builds a DoublePredicate whose parameter is to be compared for inequality to the passed double constant value. If the absolute value of the difference between the two numbers is greater than a passed delta, the values will be considered not equal.

Parameters:

value - A constant value to be compared to the parameter of the DoublePredicate built by this method.

delta - A delta value meaning that if the absolute value of the difference between the two numbers to be compared is greater than the delta, the values will be considered not equal.

Returns:

A DoublePredicate that compares its parameter to a constant double value for inequality outside of a delta value.

isDblNotEqual

public static java.util.function.DoublePredicate isDblNotEqual(java.util.function.DoubleUnaryOperator operator,
                                                               double value)

Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if the value returned by that operator is not equal to the passed constant double value. For example:

     double[] doubles = IntStream.range(1, 10).asDoubleStream().toArray();
     double[] odds = Arrays.stream(doubles)
             .filter(DblPredicateUtils.isDblNotEqual(DblMapperUtils.dblModulo(2.0D), 0.0D))
             .toArray();
 

Or, with static imports:

     double[] odds = Arrays.stream(doubles)
             .filter(isDblNotEqual(dblModulo(2.0D), 0.0D))
             .toArray();
 

Parameters:

operator - A DoubleUnaryOperator whose return value is to be compared with a passed constant double value for inequality.

value - A value to be compared to the result of the passed operator for inequality.

Returns:

A DoublePredicate whose return value is compared for inequality to a passed constant double value.

isDblNotEqual

public static java.util.function.DoublePredicate isDblNotEqual(java.util.function.DoubleUnaryOperator operator,
                                                               org.perro.functions.predicate.DoubleWithDelta doubleWithDelta)

Given a DoubleUnaryOperator this method builds a DoublePredicate that determines if a value returned by that operator is equal to a constant double value, within a delta parameter.

     double[] doubles = IntStream.range(1, 10).asDoubleStream().toArray();
     double[] odds = Arrays.stream(doubles)
             .filter(DblPredicateUtils.isDblNotEqual(DblMapperUtils.dblModulo(2.0D), DblPredicateUtils.dblWithDelta(0.0D, 0.000001D)))
             .toArray();
 

Or, with static imports:

     double[] odds = Arrays.stream(doubles)
             .filter(isDblNotEqual(dblModulo(2.0D), dblWithDelta(0.0D, 0.000001D)))
             .toArray();
 

Parameters:

operator - A DoubleUnaryOperator whose return value is to be compared with a constant double value for inequality, within a delta.

doubleWithDelta - An object containing a constant double value for comparison, and a double delta.

Returns:

A DoublePredicate whose parameter is to be applied to the passed operator, and the result is compared for equality to a constant double value. If the difference is less than or equal to a delta value, then the values are considered equal.

dblToObjContains

public static <R> java.util.function.DoublePredicate dblToObjContains(java.util.Collection<? extends R> collection,
                                                                      java.util.function.DoubleFunction<? extends R> function)

Given a Collection whose elements are of type <R>, and a DoubleFunction that returns a value of type <R>, this method builds a DoublePredicate that determines if the given collection contains the value returned by the double function. More formally, the DoublePredicate built by this method returns true if and only if the passed collection contains at least one element e such that (o == null ? e == null : o.equals(e)), o being the value returned from the passed double function.

Type Parameters:

R - The type of elements in the passed Collection. Also, the type of the value returned by the passed DoubleFunction.

Parameters:

collection - A Collection of elements of type <R>, to be checked for whether it contains a value returned from a passed DoubleFunction.

function - A DoubleFunction returning a value of type <R> to be checked for whether it is contained in a passed Collection.

Returns:

A DoublePredicate that applies the given DoubleFunction to its parameter, resulting in a value of type <R>. The DoublePredicate checks that the returned value is contained in a passed Collection.

inverseDblToObjContains

public static <R> java.util.function.DoublePredicate inverseDblToObjContains(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function,
                                                                             R value)

Given a DoubleFunction that returns a Collection<R>, this method builds a DoublePredicate that determines if the collection returned by that double function contains the passed value of type <R>. More formally, the DoublePredicate built by this method returns true if and only if the returned collection contains at least one element e such that (o == null ? e == null : o.equals(e)), o being the passed constant value of type <R>.

This method is similar to dblToObjContains(Collection, DoubleFunction), but instead of a built predicate checking whether a passed collection contains a value returned by a function, in this method it checks whether a collection returned by a double function contains a passed value.

Type Parameters:

R - The type of elements for collections returned by a passed DoubleFunction. Also, the type of the passed value.

Parameters:

function - A DoubleFunction that returns a Collection of elements of type <R>.

value - A value of type <R> to be checked for whether a Collection returned by the above DoubleFunction contains it.

Returns:

A DoublePredicate that applies the given double function to its parameter resulting in a Collection<R>. The DoublePredicate checks that the returned Collection contains a passed constant value of type <R>.

objToDblContains

public static <T> java.util.function.Predicate<T> objToDblContains(double[] doubles,
                                                                   java.util.function.ToDoubleFunction<? super T> function)

Given a double array, and a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that determines if the given array contains the value returned by the ToDoubleFunction.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

doubles - An array of doubles, to be checked for whether it contains a value returned from a passed ToDoubleFunction.

function - A ToDoubleFunction taking a value of type <T>, whose return value is to be checked for whether it is contained in a passed array.

Returns:

A Predicate that applies the given ToDoubleFunction to its parameter of type <T>. The Predicate checks that the returned value is contained in a passed array of doubles.

inverseObjToDblContains

public static <T> java.util.function.Predicate<T> inverseObjToDblContains(java.util.function.Function<T,double[]> function,
                                                                          double value)

Given a Function that takes an element of type <T> and returns an array of doubles, this method builds a Predicate that determines if the array returned by that function contains the passed constant double value.

This method is similar to objToDblContains(double[], ToDoubleFunction), but instead of a built predicate checking whether a passed array contains a value returned by a function, in this method it checks whether an array returned by a function contains a passed double value.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that returns an array of doubles.

value - A constant double value to be checked for whether an array of doubles returned by the above Function contains it.

Returns:

A Predicate that applies the given function to its parameter resulting in a double array. The Predicate checks that the returned array contains a passed constant double value.

dblIsNull

public static java.util.function.DoublePredicate dblIsNull(java.util.function.DoubleFunction<?> function)

Given a DoubleFunction that returns a value of an arbitrary type, this method builds a DoublePredicate that determines whether that returned value is null.

Parameters:

function - A DoubleFunction that returns a value of an arbitrary type.

Returns:

A DoublePredicate that applies a DoubleFunction to its parameter, which returns a value of an arbitrary type. The predicate determines whether that value is null.

dblIsNotNull

public static java.util.function.DoublePredicate dblIsNotNull(java.util.function.DoubleFunction<?> function)

Given a DoubleFunction that returns a value of an arbitrary type, this method builds a DoublePredicate that determines whether that returned value is not null.

Parameters:

function - A DoubleFunction that returns a value of an arbitrary type.

Returns:

A DoublePredicate that applies a DoubleFunction to its parameter, which returns a value of an arbitrary type. The predicate determines whether that value is not null.

dblGt

public static java.util.function.DoublePredicate dblGt(double compareTo)

Builds a DoublePredicate that determines whether a value is greater than a passed constant double value.

Parameters:

compareTo - A constant double value to be compared to the target value of a DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its target value to a passed constant double value and determines whether it is greater than that value.

dblGt

public static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate dblGt(java.util.function.DoubleFunction<? extends R> function,
                                                                                           R compareTo)

Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is greater than a passed constant value of type <R> (also a Comparable).

Type Parameters:

R - The return type of the passed DoubleFunction parameter. Also, the type of the passed constant value.

Parameters:

function - A DoubleFunction whose return value of type <R> is to be compared to the passed Comparable value of type <R>.

compareTo - A constant value of type <R> to be compared to the return value of a DoubleFunction.

Returns:

A DoublePredicate that applies a DoubleFunction to its target value, and compares its Comparable return value to a passed constant value to determine whether the return value is greater.

toDblGt

public static <T> java.util.function.Predicate<T> toDblGt(java.util.function.ToDoubleFunction<? super T> function,
                                                          double compareTo)

Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is greater than a passed constant double value.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A ToDoubleFunction that takes an element of type <T>, whose return value is to be compared by the Predicate built by this method, with a passed constant double value to see whether it is greater.

compareTo - A constant double value to be compared with a value returned by a passed ToDoubleFunction.

Returns:

A Predicate that applies a ToDoubleFunction to its target element, and compares its double return value to a passed constant value to determine whether the return value is greater.

dblGte

public static java.util.function.DoublePredicate dblGte(double compareTo)

Builds a DoublePredicate that determines whether a value is greater than or equal to a passed constant double value.

Parameters:

compareTo - A constant double value to be compared to the target value of a DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its target value to a passed constant double value and determines whether it is greater than or equal to that value.

dblGte

public static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate dblGte(java.util.function.DoubleFunction<? extends R> function,
                                                                                            R compareTo)

Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is greater than or equal to a passed constant value of type <R> (also a Comparable).

Type Parameters:

R - The return type of the passed DoubleFunction parameter. Also, the type of the passed constant value.

Parameters:

function - A DoubleFunction whose return value of type <R> is to be compared to the passed Comparable value of type <R>.

compareTo - A constant value of type <R> to be compared to the return value of a DoubleFunction.

Returns:

A DoublePredicate that applies a DoubleFunction to its target value, and compares its Comparable return value to a passed constant value to determine whether the return value is greater or equal to it.

toDblGte

public static <T> java.util.function.Predicate<T> toDblGte(java.util.function.ToDoubleFunction<? super T> function,
                                                           double compareTo)

Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is greater than or equal to a passed constant double value.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A ToDoubleFunction that takes an element of type <T>, whose return value is to be compared by the Predicate built by this method, with a passed constant double value to see whether it is greater than or equal to it.

compareTo - A constant double value to be compared with a value returned by a passed ToDoubleFunction.

Returns:

A Predicate that applies a ToDoubleFunction to its target element, and compares its double return value to a passed constant value to determine whether the return value is greater than or equal to it.

dblLt

public static java.util.function.DoublePredicate dblLt(double compareTo)

Builds a DoublePredicate that determines whether a value is less than a passed constant double value.

Parameters:

compareTo - A constant double value to be compared to the target value of a DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its target value to a passed constant double value and determines whether it is less than that value.

dblLt

public static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate dblLt(java.util.function.DoubleFunction<? extends R> function,
                                                                                           R compareTo)

Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is less than a passed constant value of type <R> (also a Comparable).

Type Parameters:

R - The return type of the passed DoubleFunction parameter. Also, the type of the passed constant value.

Parameters:

function - A DoubleFunction whose return value of type <R> is to be compared to the passed Comparable value of type <R>.

compareTo - A constant value of type <R> to be compared to the return value of a DoubleFunction.

Returns:

A DoublePredicate that applies a DoubleFunction to its target value, and compares its Comparable return value to a passed constant value to determine whether the return value is less than it.

toDblLt

public static <T> java.util.function.Predicate<T> toDblLt(java.util.function.ToDoubleFunction<? super T> function,
                                                          double compareTo)

Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is less than a passed constant double value.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A ToDoubleFunction that takes an element of type <T>, whose return value is to be compared by the Predicate built by this method, with a passed constant double value to see whether it is less than it.

compareTo - A constant double value to be compared with a value returned by a passed ToDoubleFunction.

Returns:

A Predicate that applies a ToDoubleFunction to its target element, and compares its double return value to a passed constant value to determine whether the return value is less than it.

dblLte

public static java.util.function.DoublePredicate dblLte(double compareTo)

Builds a DoublePredicate that determines whether a value is less than or equal to a passed constant double value.

Parameters:

compareTo - A constant double value to be compared to the target value of a DoublePredicate built by this method.

Returns:

A DoublePredicate that compares its target value to a passed constant double value and determines whether it is less than or equal to that value.

dblLte

public static <R extends java.lang.Comparable<R>> java.util.function.DoublePredicate dblLte(java.util.function.DoubleFunction<? extends R> function,
                                                                                            R compareTo)

Given a DoubleFunction that returns a value of type <R>, and a constant value of type <R>, this method builds a DoublePredicate that applies that function to its target value, and determines whether the returned Comparable value is less than or equal to a passed constant value of type <R> (also a Comparable).

Type Parameters:

R - The return type of the passed DoubleFunction parameter. Also, the type of the passed constant value.

Parameters:

function - A DoubleFunction whose return value of type <R> is to be compared to the passed Comparable value of type <R>.

compareTo - A constant value of type <R> to be compared to the return value of a DoubleFunction.

Returns:

A DoublePredicate that applies a DoubleFunction to its target value, and compares its Comparable return value to a passed constant value to determine whether the return value is less or equal to it.

toDblLte

public static <T> java.util.function.Predicate<T> toDblLte(java.util.function.ToDoubleFunction<? super T> function,
                                                           double compareTo)

Given a ToDoubleFunction that takes an element of type <T>, this method builds a Predicate that compares the return value of that function, and determines whether it is less than or equal to a passed constant double value.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A ToDoubleFunction that takes an element of type <T>, whose return value is to be compared by the Predicate built by this method, with a passed constant double value to see whether it is less than or equal to it.

compareTo - A constant double value to be compared with a value returned by a passed ToDoubleFunction.

Returns:

A Predicate that applies a ToDoubleFunction to its target element, and compares its double return value to a passed constant value to determine whether the return value is less than or equal to it.

isDblCollEmpty

public static java.util.function.DoublePredicate isDblCollEmpty(java.util.function.DoubleFunction<? extends java.util.Collection<?>> function)

Given a DoubleFunction that returns a Collection of elements of an arbitrary type, this method builds a DoublePredicate that determines whether the returned Collection is empty.

Parameters:

function - A DoubleFunction that returns a Collection of elements of an arbitrary type.

Returns:

A DoublePredicate that applies its parameter to a DoubleFunction that returns a Collection of elements of an arbitrary type. The DoublePredicate determines whether the returned Collection is empty.

isDblCollNotEmpty

public static java.util.function.DoublePredicate isDblCollNotEmpty(java.util.function.DoubleFunction<? extends java.util.Collection<?>> function)

Given a DoubleFunction that returns a Collection of elements of an arbitrary type, this method builds a DoublePredicate that determines whether the returned Collection is not empty.

Parameters:

function - A DoubleFunction that returns a Collection of elements of an arbitrary type.

Returns:

A DoublePredicate that applies its parameter to a DoubleFunction that returns a Collection of elements of an arbitrary type. The DoublePredicate determines whether the returned Collection is not empty.

isDblArrayEmpty

public static <T> java.util.function.Predicate<T> isDblArrayEmpty(java.util.function.Function<? super T,double[]> function)

Given a Function that returns an array of doubles, this method builds a Predicate that determines whether the returned array is empty.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that returns an array of doubles.

Returns:

A Predicate that applies its parameter to a Function that returns an array of doubles. The Predicate determines whether the returned array is empty.

isDblArrayNotEmpty

public static <T> java.util.function.Predicate<T> isDblArrayNotEmpty(java.util.function.Function<? super T,double[]> function)

Given a Function that returns an array of doubles, this method builds a Predicate that determines whether the returned array is not empty.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that returns an array of doubles.

Returns:

A Predicate that applies its parameter to a Function that returns an array of doubles. The Predicate determines whether the returned array is not empty.

objToDblsAllMatch

public static <T> java.util.function.Predicate<T> objToDblsAllMatch(java.util.function.Function<T,? extends double[]> function,
                                                                    java.util.function.DoublePredicate predicate)

Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether all doubles in the returned array match the DoublePredicate.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that takes en element of type <T> and returns an array of doubles.

predicate - A DoublePredicate that will be applied to all elements of an array of doubles returned by the passed Function.

Returns:

A Predicate that applies its target element of type <T> to a Function that returns an array of doubles. The Predicate determines whether all elements in that array match a passed DoublePredicate.

dblToObjsAllMatch

public static <R> java.util.function.DoublePredicate dblToObjsAllMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function,
                                                                       java.util.function.Predicate<R> predicate)

Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether all elements in the returned Collection match the Predicate.

Type Parameters:

R - The type of the elements of a Collection returned by a passed DoubleFunction. Also the type of elements taken by a passed Predicate that will be applied to all elements of that Collection.

Parameters:

function - A DoubleFunction that returns a Collection of elements of type <R>.

predicate - A Predicate that will be applied to all elements of a Collection returned by the passed DoubleFunction.

Returns:

A DoublePredicate that applies its parameter to a DoubleFunction that returns a Collection of elements of type <R>. The DoublePredicate determines whether all elements in that Collection match a passed Predicate.

objToDblsAnyMatch

public static <T> java.util.function.Predicate<T> objToDblsAnyMatch(java.util.function.Function<T,? extends double[]> function,
                                                                    java.util.function.DoublePredicate predicate)

Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether any of the doubles in the returned array match the DoublePredicate.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that takes en element of type <T> and returns an array of doubles.

predicate - A DoublePredicate that will be applied to all elements of an array of doubles returned by the passed Function to determine whether any match.

Returns:

A Predicate that applies its target element of type <T> to a Function that returns an array of doubles. The Predicate determines whether any of the elements in that array match a passed DoublePredicate.

dblToObjsAnyMatch

public static <R> java.util.function.DoublePredicate dblToObjsAnyMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function,
                                                                       java.util.function.Predicate<R> predicate)

Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether any of the elements in the returned Collection match the Predicate.

Type Parameters:

R - The type of the elements of a Collection returned by a passed DoubleFunction. Also the type of elements taken by a passed Predicate that will be applied to all elements of that Collection.

Parameters:

function - A DoubleFunction that returns a Collection of elements of type <R>.

predicate - A Predicate that will be applied to all elements of a Collection returned by the passed DoubleFunction to determine whether any match.

Returns:

A DoublePredicate that applies its parameter to a DoubleFunction that returns a Collection of elements of type <R>. The DoublePredicate determines whether any of the elements in that Collection match a passed Predicate.

objToDblsNoneMatch

public static <T> java.util.function.Predicate<T> objToDblsNoneMatch(java.util.function.Function<T,? extends double[]> function,
                                                                     java.util.function.DoublePredicate predicate)

Given a Function that takes an element of type <T> and returns an array of doubles, and a DoublePredicate, this method builds a Predicate that determines whether none of the doubles in the returned array match the DoublePredicate.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A Function that takes en element of type <T> and returns an array of doubles.

predicate - A DoublePredicate that will be applied to all elements of an array of doubles returned by the passed Function to determine whether none match.

Returns:

A Predicate that applies its target element of type <T> to a Function that returns an array of doubles. The Predicate determines whether none of the elements in that array match a passed DoublePredicate.

dblToObjsNoneMatch

public static <R> java.util.function.DoublePredicate dblToObjsNoneMatch(java.util.function.DoubleFunction<? extends java.util.Collection<R>> function,
                                                                        java.util.function.Predicate<R> predicate)

Given a DoubleFunction that returns a Collection of type <R>, and a Predicate, this method builds a DoublePredicate that determines whether none of the elements in the returned Collection match the Predicate.

Type Parameters:

R - The type of the elements of a Collection returned by a passed DoubleFunction. Also the type of elements taken by a passed Predicate that will be applied to all elements of that Collection.

Parameters:

function - A DoubleFunction that returns a Collection of elements of type <R>.

predicate - A Predicate that will be applied to all elements of a Collection returned by the passed DoubleFunction to determine whether none match.

Returns:

A DoublePredicate that applies its parameter to a DoubleFunction that returns a Collection of elements of type <R>. The DoublePredicate determines whether none of the elements in that Collection match a passed Predicate.

mapToDblAndFilter

public static <T> java.util.function.Predicate<T> mapToDblAndFilter(java.util.function.ToDoubleFunction<? super T> function,
                                                                    java.util.function.DoublePredicate predicate)

Given a ToDoubleFunction taking a value of type <T>, and a DoublePredicate, this method builds a Predicate that takes an element of type <T>, and applies the return value of the ToDoubleFunction to the given predicate. It is a way of adapting a DoublePredicate to a Stream of a different type. For example, the DblStreamUtils.indexOfFirstDbl(double[], DoublePredicate) method uses this predicate in its implementation (Note that the dblPairWithIndex() below refers to DblMapperUtils.dblPairWithIndex()):

 public static int indexOfFirstDbl(double[] doubles, DoublePredicate doublePredicate) {
     return defaultDblStream(doubles)
         .mapToObj(dblPairWithIndex())
         .filter(mapToDblAndFilter(DoubleIndexPair::getDoubleValue, doublePredicate))
         .mapToInt(DoubleIndexPair::getIndex)
         .findFirst()
         .orElse(-1);
 }
 

The map-and-filter predicate is necessary in this case because we have a predicate that operates on the original double type of the stream, but a mapping operation has changed the type to a DoubleIndexPair. The DoubleIndexPair::getDoubleValue method reference, passed as the ToDoubleFunction argument to this method, retrieves the original double value before the DoublePredicate evaluates it.

As a side note, the pairing of an object with another can be very useful in streaming operations. In this case, we need to have both the double value and its index available at the same point in the stream, so we temporarily pair the two together, before mapping to just the index.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A ToDoubleFunction to transform an element of type <T> to a double before it is passed to a DoublePredicate.

predicate - A DoublePredicate whose value will be retrieved from a given transformer function.

Returns:

A Predicate that takes an element of type <T>, and applies the return value of a passed ToDoubleFunction to a passed DoublePredicate.

dblMapAndFilter

public static <T> java.util.function.DoublePredicate dblMapAndFilter(java.util.function.DoubleFunction<? extends T> function,
                                                                     java.util.function.Predicate<? super T> predicate)

Given a DoubleFunction that returns a value of type <T>, and a Predicate, this method builds a DoublePredicate that applies the return value of the DoubleFunction to the given predicate. It is a way of adapting a double value to a Predicate. This method is the inverse of mapToDblAndFilter(ToDoubleFunction, DoublePredicate). In that method, we map from a value of type <T> to a double, and then apply a DoublePredicate. In this method we map from a double to a value of type <T>, and then apply a Predicate<T>.

Type Parameters:

T - The type of the element taken by the Predicate built by this method.

Parameters:

function - A DoubleFunction to transform a double value to an element of type <T> before it is passed to a Predicate.

predicate - A Predicate whose value will be retrieved from a given DoubleFunction.

Returns:

A DoublePredicate that applies the return value of a passed DoubleFunction to a passed Predicate.

dblWithDelta

public static org.perro.functions.predicate.DoubleWithDelta dblWithDelta(double value,
                                                                         double delta)

Combines a double value for use in a comparison, with a delta. When an equality comparison is made, if the difference in values is smaller than the delta, then the values are considered equal. This method is used to build the second parameter to the isDblEqual(DoubleUnaryOperator, DoubleWithDelta) and isDblNotEqual(DoubleUnaryOperator, DoubleWithDelta) methods.

Parameters:

value - A double value to be compared with another value.

delta - A delta value to be used - if the difference of two values is within it, they are still considered equal.

Returns:

An object encapsulating a double value for comparison, and a delta value.