org.apache.commons.collections.functors.IfClosure Maven / Gradle / Ivy
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* 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.collections.functors;
import java.io.Serializable;
import org.apache.commons.collections.Closure;
import org.apache.commons.collections.Predicate;
/**
* Closure implementation acts as an if statement calling one or other closure
* based on a predicate.
*
* @since Commons Collections 3.0
* @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
*
* @author Stephen Colebourne
* @author Matt Benson
*/
public class IfClosure implements Closure, Serializable {
/** Serial version UID */
private static final long serialVersionUID = 3518477308466486130L;
/** The test */
private final Predicate iPredicate;
/** The closure to use if true */
private final Closure iTrueClosure;
/** The closure to use if false */
private final Closure iFalseClosure;
/**
* Factory method that performs validation.
*
* This factory creates a closure that performs no action when
* the predicate is false.
*
* @param predicate predicate to switch on
* @param trueClosure closure used if true
* @return the if closure
* @throws IllegalArgumentException if either argument is null
* @since Commons Collections 3.2
*/
public static Closure getInstance(Predicate predicate, Closure trueClosure) {
return getInstance(predicate, trueClosure, NOPClosure.INSTANCE);
}
/**
* Factory method that performs validation.
*
* @param predicate predicate to switch on
* @param trueClosure closure used if true
* @param falseClosure closure used if false
* @return the if closure
* @throws IllegalArgumentException if any argument is null
*/
public static Closure getInstance(Predicate predicate, Closure trueClosure, Closure falseClosure) {
if (predicate == null) {
throw new IllegalArgumentException("Predicate must not be null");
}
if (trueClosure == null || falseClosure == null) {
throw new IllegalArgumentException("Closures must not be null");
}
return new IfClosure(predicate, trueClosure, falseClosure);
}
/**
* Constructor that performs no validation.
* Use getInstance if you want that.
*
* This constructor creates a closure that performs no action when
* the predicate is false.
*
* @param predicate predicate to switch on, not null
* @param trueClosure closure used if true, not null
* @since Commons Collections 3.2
*/
public IfClosure(Predicate predicate, Closure trueClosure) {
this(predicate, trueClosure, NOPClosure.INSTANCE);
}
/**
* Constructor that performs no validation.
* Use getInstance if you want that.
*
* @param predicate predicate to switch on, not null
* @param trueClosure closure used if true, not null
* @param falseClosure closure used if false, not null
*/
public IfClosure(Predicate predicate, Closure trueClosure, Closure falseClosure) {
super();
iPredicate = predicate;
iTrueClosure = trueClosure;
iFalseClosure = falseClosure;
}
/**
* Executes the true or false closure accoring to the result of the predicate.
*
* @param input the input object
*/
public void execute(Object input) {
if (iPredicate.evaluate(input) == true) {
iTrueClosure.execute(input);
} else {
iFalseClosure.execute(input);
}
}
/**
* Gets the predicate.
*
* @return the predicate
* @since Commons Collections 3.1
*/
public Predicate getPredicate() {
return iPredicate;
}
/**
* Gets the closure called when true.
*
* @return the closure
* @since Commons Collections 3.1
*/
public Closure getTrueClosure() {
return iTrueClosure;
}
/**
* Gets the closure called when false.
*
* @return the closure
* @since Commons Collections 3.1
*/
public Closure getFalseClosure() {
return iFalseClosure;
}
}