de.unkrig.commons.lang.protocol

Class TransformerUtil

java.lang.Object

de.unkrig.commons.lang.protocol.TransformerUtil

public final class TransformerUtil
extends java.lang.Object

Various Transformer-related utility methods.

Method Summary

Modifier and Type	Method and Description
static <I,O> Transformer<I,O>	addMappings(Transformer<? super I,O> transformer, java.lang.Object... keysAndValues)
static <I,O,EX extends java.lang.RuntimeException> Transformer<I,O>	asTransformer(TransformerWhichThrows<? super I,? extends O,EX> source) Converts a TransformerWhichThrows into a Transformer.
static <I,O,EX extends java.lang.Throwable> TransformerWhichThrows<I,O,EX>	asTransformerWhichThrows(Transformer<? super I,? extends O> source) Converts a Transformer into a TransformerWhichThrows.
static <I,O> Transformer<I,O>	cache(Transformer<? super I,O> delegate) A transformer which lets a delegate transform the inputs, but at most once for each non-equal input.
static <I,O> Transformer<I,O>	combine(I extraInput, O extraOutput, Transformer<? super I,O> delegate)
static <I,O,EX extends java.lang.Exception> TransformerWhichThrows<I,O,EX>	combine(I extraInput, O extraOutput, TransformerWhichThrows<? super I,O,EX> delegate)
static <I,O> Transformer<I,O>	fromMappings(java.lang.Object... keysAndValues)
static <O,I extends O> Transformer<I,O>	identity()

Methods inherited from class java.lang.Object

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

Method Detail

identity

public static <O,I extends O> Transformer<I,O> identity()

Returns:

A Transformer that transforms any object reference to itself.

asTransformerWhichThrows

public static <I,O,EX extends java.lang.Throwable> TransformerWhichThrows<I,O,EX> asTransformerWhichThrows(Transformer<? super I,? extends O> source)

Converts a Transformer into a TransformerWhichThrows.

That is possible iff:

• The target's input type is a subclass of the source's input type, and
• The source's output type is a subclass of the target's output type.

Type Parameters:

I - The transformers' input type

O - The transformers' output type

EX - The target transformer's exception

asTransformer

public static <I,O,EX extends java.lang.RuntimeException> Transformer<I,O> asTransformer(TransformerWhichThrows<? super I,? extends O,EX> source)

Converts a TransformerWhichThrows into a Transformer.

That is possible iff:

• The target's input type is a subclass of the source's input type, and
• The source's output type is a subclass of the target's output type
• The source's exception is a subclass of RuntimeException.

Type Parameters:

I - The transformers' input type

O - The transformers' output type

EX - The source transformer's exception

combine

public static <I,O> Transformer<I,O> combine(I extraInput,
                                             O extraOutput,
                                             Transformer<? super I,O> delegate)

Returns:

A Transformer which calls the delegate, except when the subject equals the extraInput, when it returns extraOutput

combine

public static <I,O,EX extends java.lang.Exception> TransformerWhichThrows<I,O,EX> combine(I extraInput,
                                                                                          O extraOutput,
                                                                                          TransformerWhichThrows<? super I,O,EX> delegate)

Returns:

A TransformerWhichThrows which calls the delegate, except when the subject equals the extraInput, when it returns extraOutput

addMappings

public static <I,O> Transformer<I,O> addMappings(Transformer<? super I,O> transformer,
                                                 java.lang.Object... keysAndValues)

Returns:

A Transformer in which the given keys and values override the mappings of the delegate.

fromMappings

public static <I,O> Transformer<I,O> fromMappings(java.lang.Object... keysAndValues)

Returns:

A Transformer in which the given keys and values override the mappings of the delegate.

cache

public static <I,O> Transformer<I,O> cache(Transformer<? super I,O> delegate)

A transformer which lets a delegate transform the inputs, but at most once for each non-equal input.