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/*******************************************************************************
* Copyright (c) 2016 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0, which accompanies this distribution
* and is available at http://www.eclipse.org/legal/epl-v10.html.
*
* Contributors:
* Oracle - initial API and implementation
******************************************************************************/
package org.eclipse.jpt.common.utility.internal.predicate;
import java.io.Serializable;
import java.util.Collection;
import org.eclipse.jpt.common.utility.predicate.Predicate;
/**
* Singleton predicate that evaluates whether a collection is empty.
*/
public final class CollectionIsEmptyPredicate
implements Predicate<Collection<?>>, Serializable
{
public static final Predicate<Collection<?>> INSTANCE = new CollectionIsEmptyPredicate();
public static Predicate<Collection<?>> instance() {
return INSTANCE;
}
// ensure single instance
private CollectionIsEmptyPredicate() {
super();
}
/**
* Return whether the collection is empty.
*/
public boolean evaluate(Collection<?> collection) {
return collection.isEmpty();
}
@Override
public String toString() {
return this.getClass().getSimpleName();
}
private static final long serialVersionUID = 1L;
private Object readResolve() {
// replace this object with the singleton
return INSTANCE;
}
}
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