org.fujion.common

Class MiscUtil

java.lang.Object

org.fujion.common.MiscUtil

public class MiscUtil
extends Object

Miscellaneous utility methods.

Method Summary

Modifier and Type	Method and Description
static <T> T	asNull(Supplier<T> supplier) If the supplier produces a null pointer or index-out-of-bounds exception, returns null.
static <T> T	castTo(Object value, Class<T> type) Casts a value to the specified type, returning null if the cast is not possible.
static boolean	fileExists(String fileName) Returns true if the specified file exists.
static Class<?>	firstAssignable(Class<?> type, Class<?>... candidates) Returns the first class from a list of candidate classes that is assignable from the specified type.
static Class<?>	firstAssignable(Class<?> type, Collection<Class<?>> candidates) Returns the first class in a collection of candidate classes that is assignable from the specified type.
static String	formatExceptionForDisplay(Throwable exc) Formats an exception for display.
static Class<?>[]	getParameterTypes(Object... parameters) Returns an array of parameter types given an array of parameters.
static Pattern	globToRegex(String glob) Converts a glob search pattern to a regular expression.
static <T> T	throwUnchecked(Throwable e) Throws an exception, converting it to unchecked as necessary.
static RuntimeException	toUnchecked(Throwable e) Converts a checked exception to unchecked.
static <T> T	withDefault(T deflt, Supplier<T> supplier) If the supplier produces a null pointer or index-out-of-bounds exception, returns the default value.

Methods inherited from class java.lang.Object

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

Method Detail

fileExists

public static boolean fileExists(String fileName)

Returns true if the specified file exists.

Parameters:

fileName - File name.

Returns:

True if file exists.

toUnchecked

public static RuntimeException toUnchecked(Throwable e)

Converts a checked exception to unchecked. If the original exception is already unchecked, it is simply returned.

Parameters:

e - The original exception.

Returns:

The returned unchecked exception.

throwUnchecked

public static <T> T throwUnchecked(Throwable e)

Throws an exception, converting it to unchecked as necessary. Can be used as a function or method.

Type Parameters:

T - Arbitrary return type.

Parameters:

e - The original exception. If null, no exception is thrown.

Returns:

Never returns a value.

formatExceptionForDisplay

public static String formatExceptionForDisplay(Throwable exc)

Formats an exception for display.

Parameters:

exc - Exception to format.

Returns:

The displayable form of the exception.

asNull

public static <T> T asNull(Supplier<T> supplier)

If the supplier produces a null pointer or index-out-of-bounds exception, returns null. This is the equivalent of optional chaining.

Type Parameters:

T - The type of the value.

Parameters:

supplier - The supplier of the value.

Returns:

The returned value, possibly null.

withDefault

public static <T> T withDefault(T deflt,
                                Supplier<T> supplier)

If the supplier produces a null pointer or index-out-of-bounds exception, returns the default value. This is the equivalent of optional chaining.

Type Parameters:

T - The type of the value.

Parameters:

deflt - The default value to use.

supplier - The supplier of the value.

Returns:

The returned value, possibly null.

getParameterTypes

public static Class<?>[] getParameterTypes(Object... parameters)

Returns an array of parameter types given an array of parameters. Unlike other libraries, this allows null parameter values.

Parameters:

parameters - Array of parameters.

Returns:

Array of parameter types.

castTo

public static <T> T castTo(Object value,
                           Class<T> type)

Casts a value to the specified type, returning null if the cast is not possible.

Type Parameters:

T - The type to cast to.

Parameters:

value - The value to cast.

type - The type to cast to.

Returns:

The original value, cast to the specified type, or null if the cast is not possible.

firstAssignable

public static Class<?> firstAssignable(Class<?> type,
                                       Class<?>... candidates)

Returns the first class from a list of candidate classes that is assignable from the specified type.

Parameters:

type - The type.

candidates - A list of candidate types.

Returns:

The first class that is assignable from the specified type.

firstAssignable

public static Class<?> firstAssignable(Class<?> type,
                                       Collection<Class<?>> candidates)

Returns the first class in a collection of candidate classes that is assignable from the specified type.

Parameters:

type - The type.

candidates - A collection of candidate types.

Returns:

The first class that is assignable from the specified type.

globToRegex

public static Pattern globToRegex(String glob)

Converts a glob search pattern to a regular expression.

Parameters:

glob - Glob search pattern.

Returns:

Regular expression.