cern.entwined

Class Utils

java.lang.Object

cern.entwined.Utils

public class Utils
extends Object

Oasis wide facility methods. Such as argument validity check.

Author:

Ivan Koblik

Field Summary

Fields

Modifier and Type	Field and Description
static com.google.common.base.Predicate<String>	NOT_EMPTY Predicate that accepts a string and returns true if given string is not null and is not composed of only 0 or many spaces.

Constructor Summary

Constructors

Constructor and Description
Utils()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> Collection<T>	checkEmpty(String name, Collection<T> collection) A facility method that checks collection on null and emptiness and throws IllegalArgumentException if it is.
static String	checkNull(String name, String value) A facility method that checks object to be null and throws the IllegalArgumentException if it is.
static <T> T	checkNull(String name, T value) A facility method that checks object to be null and throws the IllegalArgumentException if it is.
static <T> T	checkNullState(String message, T value) A facility method that checks object to be null and throws the IllegalStateException if it is.
static <T> List<T>	drainQueue(Queue<T> queue) Drains the queue to a new List.
static String	getStackTrace(Throwable throwable) Prints exception stack into a string and returns it.
static <T> T	getUnique(Collection<T> collection) Returns the only element in the given collection.
static boolean	hasCause(Throwable exception, Class<? extends Throwable> causeClass) Walks the exception cause list and checks if any of them are of the give type.
static <T> String	join(Iterable<T> sequence, String delimiter) Join string representation of the elements of the given collection separated with the given delimiter.
static double	round(double value, int power) Relaxes precision up to the given power of 2.

Methods inherited from class java.lang.Object

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

Field Detail

NOT_EMPTY

public static com.google.common.base.Predicate<String> NOT_EMPTY

Predicate that accepts a string and returns true if given string is not null and is not composed of only 0 or many spaces.

Constructor Detail

Utils

public Utils()

Method Detail

checkNull

public static <T> T checkNull(String name,
              T value)

A facility method that checks object to be null and throws the IllegalArgumentException if it is. This method can be chained as it returns the value in case of success.

Type Parameters:

T - Type of the checked and returned value.

Parameters:

name - The object's name.

value - The object.

Returns:

The passed object.

checkNull

public static String checkNull(String name,
               String value)

A facility method that checks object to be null and throws the IllegalArgumentException if it is. This method can be chained as it returns the value in case of success.

Parameters:

name - The object's name.

value - The object.

Returns:

The passed value string in case of success.

checkEmpty

public static <T> Collection<T> checkEmpty(String name,
                           Collection<T> collection)

A facility method that checks collection on null and emptiness and throws IllegalArgumentException if it is. This method can be chained as it returns the value in case of success.

Type Parameters:

T - The collection element type.

Parameters:

name - The collection's name

collection - The collection.

Returns:

The passed collection in case of success.

hasCause

public static boolean hasCause(Throwable exception,
               Class<? extends Throwable> causeClass)

Walks the exception cause list and checks if any of them are of the give type.

Parameters:

exception - The exception that holds the list of causes.

causeClass - The searched exception cause class type, exception itself is also checked.

Returns:

true if exception or any of its causes has the required class type.

checkNullState

public static <T> T checkNullState(String message,
                   T value)

A facility method that checks object to be null and throws the IllegalStateException if it is.

Parameters:

message - The object's name.

value - The object.

round

public static double round(double value,
           int power)

Relaxes precision up to the given power of 2.

Note: After applying this method you might still have digits on positions further then requested! This method doesn't guarantee zeroes there, but it makes sure that if there is any difference in the original numbers that is less than pow(2,power) it will be discarded.

Parameters:

value - The value to round.

power - Powers of 2 yielding the cutoff value.

Returns:

The rounded value.

join

public static <T> String join(Iterable<T> sequence,
              String delimiter)

Join string representation of the elements of the given collection separated with the given delimiter.

Parameters:

sequence - The items to be converted into string.

delimiter - The delimiter to be used between distinct items of the collection.

Returns:

String representations of the collection's items separated with the given delimiter.

drainQueue

public static <T> List<T> drainQueue(Queue<T> queue)

Drains the queue to a new List.

Type Parameters:

T - The type of elements in the queue.

Parameters:

queue - The Queue to be drained.

Returns:

List of elements from the queue in the same order as they were added to the queue.

getUnique

public static <T> T getUnique(Collection<T> collection)

Returns the only element in the given collection.

Parameters:

collection - The collection of elements that is expected to be of size 1.

Returns:

The only element in the collection.

Throws:

IllegalStateException - If the collection size is different from 1.

getStackTrace

public static String getStackTrace(Throwable throwable)

Prints exception stack into a string and returns it.

Parameters:

throwable - The throwable which stack trace needs to be printed.

Returns:

The stack trace.