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Types that extend and augment the Java Collections Framework.
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2001-2004 The Apache Software Foundation. All rights
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* modification, are permitted provided that the following conditions
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* any, must include the following acknowledgement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgement may appear in the software itself,
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*
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*/
package org.apache.commons.collections.functors;
import java.io.Serializable;
import org.apache.commons.collections.Closure;
import org.apache.commons.collections.Predicate;
/**
* Closure implementation that executes a closure repeatedly until a condition is met,
* like a do-while or while loop.
*
* @since Commons Collections 3.0
* @version $Revision: 1.2 $ $Date: 2004/01/14 21:43:09 $
*
* @author Stephen Colebourne
*/
public class WhileClosure implements Closure, Serializable {
/** Serial version UID */
static final long serialVersionUID = -3110538116913760108L;
/** The test condition */
private final Predicate iPredicate;
/** The closure to call */
private final Closure iClosure;
/** The flag, true is a do loop, false is a while */
private final boolean iDoLoop;
/**
* Factory method that performs validation.
*
* @param predicate the predicate used to evaluate when the loop terminates, not null
* @param closure the closure the execute, not null
* @param doLoop true to act as a do-while loop, always executing the closure once
* @return the while
closure
* @throws IllegalArgumentException if the predicate or closure is null
*/
public static Closure getInstance(Predicate predicate, Closure closure, boolean doLoop) {
if (predicate == null) {
throw new IllegalArgumentException("Predicate must not be null");
}
if (closure == null) {
throw new IllegalArgumentException("Closure must not be null");
}
return new WhileClosure(predicate, closure, doLoop);
}
/**
* Constructor that performs no validation.
* Use getInstance
if you want that.
*
* @param predicate the predicate used to evaluate when the loop terminates, not null
* @param closure the closure the execute, not null
* @param doLoop true to act as a do-while loop, always executing the closure once
*/
public WhileClosure(Predicate predicate, Closure closure, boolean doLoop) {
super();
iPredicate = predicate;
iClosure = closure;
iDoLoop = doLoop;
}
/**
* Execute the closure until the predicate is false.
*/
public void execute(Object input) {
if (iDoLoop) {
iClosure.execute(input);
}
while (iPredicate.evaluate(input)) {
iClosure.execute(input);
}
}
}