Author: tn
Date: Sun Dec 8 11:41:03 2013
New Revision: 1549021
URL: http://svn.apache.org/r1549021
Log:
[COLLECTIONS-503] Added new IfTransformer and deprecate
TransformerUtils.switchTransformer(Predicate, Transformer, Transformer). Thanks
to Josh Cain.
Added:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
(with props)
Modified:
commons/proper/collections/trunk/src/changes/changes.xml
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/TransformerUtils.java
commons/proper/collections/trunk/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
Modified: commons/proper/collections/trunk/src/changes/changes.xml
URL:
http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/changes/changes.xml?rev=1549021&r1=1549020&r2=1549021&view=diff
==============================================================================
--- commons/proper/collections/trunk/src/changes/changes.xml (original)
+++ commons/proper/collections/trunk/src/changes/changes.xml Sun Dec 8
11:41:03 2013
@@ -22,8 +22,12 @@
<body>
<release version="4.0.1" date="TBD" description="">
+ <action issue="COLLECTIONS-503" dev="tn" type="add" due-to="Josh Cain">
+ Added new transformer "IfTransformer" and factory methods
"TransformerUtils#ifTransformer(...)"
+ which replace "TransformerUtils#switchTransformer(Predicate,
Transformer, Transformer)".
+ </action>
<action issue="COLLECTIONS-471" dev="tn" type="add" due-to="Radford Tam">
- Added new decorator "BoundedIterator".
+ Added new decorator "BoundedIterator" and factory methods
"IteratorUtils#boundedIterator(...)".
</action>
</release>
<release version="4.0" date="2013-11-27" description="
Modified:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/TransformerUtils.java
URL:
http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/TransformerUtils.java?rev=1549021&r1=1549020&r2=1549021&view=diff
==============================================================================
---
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/TransformerUtils.java
(original)
+++
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/TransformerUtils.java
Sun Dec 8 11:41:03 2013
@@ -26,6 +26,7 @@ import org.apache.commons.collections4.f
import org.apache.commons.collections4.functors.EqualPredicate;
import org.apache.commons.collections4.functors.ExceptionTransformer;
import org.apache.commons.collections4.functors.FactoryTransformer;
+import org.apache.commons.collections4.functors.IfTransformer;
import org.apache.commons.collections4.functors.InstantiateTransformer;
import org.apache.commons.collections4.functors.InvokerTransformer;
import org.apache.commons.collections4.functors.MapTransformer;
@@ -45,6 +46,7 @@ import org.apache.commons.collections4.f
* <li>Predicate - returns the result of the predicate as a Boolean
* <li>Factory - returns a new object from a factory
* <li>Chained - chains two or more transformers together
+ * <li>If - calls one transformer or another based on a predicate
* <li>Switch - calls one transformer based on one or more predicates
* <li>SwitchMap - calls one transformer looked up from a Map
* <li>Instantiate - the Class input object is instantiated
@@ -211,6 +213,43 @@ public class TransformerUtils {
}
/**
+ * Create a new Transformer that calls the transformer if the predicate is
true,
+ * otherwise the input object is returned unchanged.
+ *
+ * @param <T> the input / output type
+ * @param predicate the predicate to switch on
+ * @param trueTransformer the transformer called if the predicate is true
+ * @return the transformer
+ * @throws IllegalArgumentException if either the predicate or transformer
is null
+ * @see org.apache.commons.collections4.functors.IfTransformer
+ * @since 4.0.1
+ */
+ public static <T> Transformer<T, T> ifTransformer(final Predicate<? super
T> predicate,
+ final Transformer<?
super T, ? extends T> trueTransformer) {
+ return IfTransformer.ifTransformer(predicate, trueTransformer);
+ }
+
+ /**
+ * Create a new Transformer that calls one of two transformers depending
+ * on the specified predicate.
+ *
+ * @param <I> the input type
+ * @param <O> the output type
+ * @param predicate the predicate to switch on
+ * @param trueTransformer the transformer called if the predicate is true
+ * @param falseTransformer the transformer called if the predicate is
false
+ * @return the transformer
+ * @throws IllegalArgumentException if either the predicate or transformer
is null
+ * @see org.apache.commons.collections4.functors.IfTransformer
+ * @since 4.0.1
+ */
+ public static <I, O> Transformer<I, O> ifTransformer(final Predicate<?
super I> predicate,
+ final Transformer<?
super I, ? extends O> trueTransformer,
+ final Transformer<?
super I, ? extends O> falseTransformer) {
+ return IfTransformer.ifTransformer(predicate, trueTransformer,
falseTransformer);
+ }
+
+ /**
* Create a new Transformer that calls one of two transformers depending
* on the specified predicate.
*
@@ -222,8 +261,10 @@ public class TransformerUtils {
* @return the transformer
* @throws IllegalArgumentException if either the predicate or transformer
is null
* @see org.apache.commons.collections4.functors.SwitchTransformer
+ * @deprecated as of 4.0.1, use {@link #ifTransformer(Predicate,
Transformer, Transformer))
*/
@SuppressWarnings("unchecked")
+ @Deprecated
public static <I, O> Transformer<I, O> switchTransformer(final Predicate<?
super I> predicate,
final Transformer<? super I, ? extends O> trueTransformer,
final Transformer<? super I, ? extends O> falseTransformer) {
Added:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
URL:
http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java?rev=1549021&view=auto
==============================================================================
---
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
(added)
+++
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
Sun Dec 8 11:41:03 2013
@@ -0,0 +1,152 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.collections4.functors;
+
+import org.apache.commons.collections4.Predicate;
+import org.apache.commons.collections4.Transformer;
+
+import java.io.Serializable;
+
+/**
+ * Transformer implementation that will call one of two closures based on
whether a predicate evaluates
+ * as true or false.
+ *
+ * @param <I> The input type for the transformer
+ * @param <O> The output type for the transformer
+ *
+ * @since 4.0.1
+ * @version $Id$
+ */
+public class IfTransformer<I, O> implements Transformer<I, O>, Serializable {
+
+ /** Serial version UID */
+ private static final long serialVersionUID = 8069309411242014252L;
+
+ /** The test */
+ private final Predicate<? super I> iPredicate;
+ /** The transformer to use if true */
+ private final Transformer<? super I, ? extends O> iTrueTransformer;
+ /** The transformer to use if false */
+ private final Transformer<? super I, ? extends O> iFalseTransformer;
+
+ /**
+ * Factory method that performs validation.
+ *
+ * @param <I> input type for the transformer
+ * @param <O> output type for the transformer
+ * @param predicate predicate to switch on
+ * @param trueTransformer transformer used if true
+ * @param falseTransformer transformer used if false
+ * @return the <code>if</code> transformer
+ */
+ public static <I, O> Transformer<I, O> ifTransformer(final Predicate<?
super I> predicate,
+ final Transformer<?
super I, ? extends O> trueTransformer,
+ final Transformer<?
super I, ? extends O> falseTransformer) {
+ if (predicate == null) {
+ throw new IllegalArgumentException("Predicate must not be null");
+ }
+ if (trueTransformer == null || falseTransformer == null) {
+ throw new IllegalArgumentException("Transformers must not be
null");
+ }
+
+ return new IfTransformer<I, O>(predicate, trueTransformer,
falseTransformer);
+ }
+
+ /**
+ * Factory method that performs validation.
+ * <p>
+ * This factory creates a transformer that just returns the input object
when
+ * the predicate is false.
+ *
+ * @param <T> input and output type for the transformer
+ * @param predicate predicate to switch on
+ * @param trueTransformer transformer used if true
+ * @return the <code>if</code> transformer
+ */
+ public static <T> Transformer<T, T> ifTransformer(
+ final Predicate<? super T> predicate,
+ final Transformer<? super T, ? extends T> trueTransformer) {
+
+ if (predicate == null) {
+ throw new IllegalArgumentException("Predicate must not be null");
+ }
+ if (trueTransformer == null) {
+ throw new IllegalArgumentException("Transformer must not be null");
+ }
+
+ return new IfTransformer<T, T>(predicate, trueTransformer,
NOPTransformer.<T>nopTransformer());
+ }
+
+ /**
+ * Constructor that performs no validation.
+ * Use the static factory method <code>ifTransformer</code> if you want
that.
+ *
+ * @param predicate predicate to switch on, not null
+ * @param trueTransformer transformer used if true, not null
+ * @param falseTransformer transformer used if false, not null
+ */
+ public IfTransformer(final Predicate<? super I> predicate,
+ final Transformer<? super I, ? extends O> trueTransformer,
+ final Transformer<? super I, ? extends O> falseTransformer) {
+
+ super();
+ iPredicate = predicate;
+ iTrueTransformer = trueTransformer;
+ iFalseTransformer = falseTransformer;
+ }
+
+ /**
+ * Transforms the input using the true or false transformer based to the
result of the predicate.
+ *
+ * @param input the input object to transform
+ * @return the transformed result
+ */
+ public O transform(final I input) {
+ if(iPredicate.evaluate(input)){
+ return iTrueTransformer.transform(input);
+ } else {
+ return iFalseTransformer.transform(input);
+ }
+ }
+
+ /**
+ * Gets the predicate.
+ *
+ * @return the predicate
+ */
+ public Predicate<? super I> getPredicate(){
+ return iPredicate;
+ }
+
+ /**
+ * Gets the transformer used when true.
+ *
+ * @return the transformer
+ */
+ public Transformer<? super I, ? extends O> getTrueTransformer() {
+ return iTrueTransformer;
+ }
+
+ /**
+ * Gets the transformer used when false.
+ *
+ * @return the transformer
+ */
+ public Transformer<? super I, ? extends O> getFalseTransformer() {
+ return iFalseTransformer;
+ }
+}
Propchange:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
------------------------------------------------------------------------------
svn:eol-style = native
Propchange:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
------------------------------------------------------------------------------
svn:keywords = Id Revision HeadURL
Propchange:
commons/proper/collections/trunk/src/main/java/org/apache/commons/collections4/functors/IfTransformer.java
------------------------------------------------------------------------------
svn:mime-type = text/plain
Modified:
commons/proper/collections/trunk/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java?rev=1549021&r1=1549020&r2=1549021&view=diff
==============================================================================
---
commons/proper/collections/trunk/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
(original)
+++
commons/proper/collections/trunk/src/test/java/org/apache/commons/collections4/TransformerUtilsTest.java
Sun Dec 8 11:41:03 2013
@@ -235,6 +235,49 @@ public class TransformerUtilsTest extend
} catch (final IllegalArgumentException ex) {}
}
+ // ifTransformer
+ //------------------------------------------------------------------
+
+ public void testIfTransformer() {
+ final Transformer<Object, String> a =
TransformerUtils.constantTransformer("A");
+ final Transformer<Object, String> b =
TransformerUtils.constantTransformer("B");
+ final Transformer<Object, String> c =
TransformerUtils.constantTransformer("C");
+
+ assertEquals("A",
TransformerUtils.ifTransformer(TruePredicate.truePredicate(), a,
b).transform(null));
+ assertEquals("B",
TransformerUtils.ifTransformer(FalsePredicate.falsePredicate(), a,
b).transform(null));
+
+ Predicate<Integer> lessThanFivePredicate = new Predicate<Integer>() {
+ public boolean evaluate(Integer value) {
+ return value < 5;
+ }
+ };
+ // if/else tests
+ assertEquals("A", TransformerUtils.<Integer,
String>ifTransformer(lessThanFivePredicate, a, b).transform(1));
+ assertEquals("B", TransformerUtils.<Integer,
String>ifTransformer(lessThanFivePredicate, a, b).transform(5));
+
+ // if tests
+ Predicate<String> equalsAPredicate =
EqualPredicate.equalPredicate("A");
+ assertEquals("C",
TransformerUtils.<String>ifTransformer(equalsAPredicate, c).transform("A"));
+ assertEquals("B",
TransformerUtils.<String>ifTransformer(equalsAPredicate, c).transform("B"));
+
+ try {
+ TransformerUtils.ifTransformer(null, null);
+ fail();
+ } catch (final IllegalArgumentException ex) {}
+ try {
+ TransformerUtils.ifTransformer(TruePredicate.truePredicate(),
null);
+ fail();
+ } catch (final IllegalArgumentException ex) {}
+ try {
+ TransformerUtils.ifTransformer(null,
ConstantTransformer.constantTransformer("A"));
+ fail();
+ } catch (final IllegalArgumentException ex) {}
+ try {
+ TransformerUtils.ifTransformer(null, null, null);
+ fail();
+ } catch (final IllegalArgumentException ex) {}
+ }
+
// switchTransformer
//------------------------------------------------------------------
