com.liferay.portal.kernel.util.MappingEnumeration Maven / Gradle / Ivy
/**
* Copyright (c) 2000-present Liferay, Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1 of the License, or (at your option)
* any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*/
package com.liferay.portal.kernel.util;
import java.util.Enumeration;
import java.util.NoSuchElementException;
/**
* @author Shuyang Zhou
*/
public class MappingEnumeration implements Enumeration {
public MappingEnumeration(Enumeration enumeration, Mapper mapper) {
this.enumeration = enumeration;
this.mapper = mapper;
nextElement = nextMappedElement();
}
@Override
public boolean hasMoreElements() {
if (nextElement != null) {
return true;
}
return false;
}
@Override
public R nextElement() {
if (nextElement == null) {
throw new NoSuchElementException();
}
R nextElement = this.nextElement;
this.nextElement = nextMappedElement();
return nextElement;
}
public interface Mapper {
public R map(T t);
}
protected final R nextMappedElement() {
while (enumeration.hasMoreElements()) {
R element = mapper.map(enumeration.nextElement());
if (element != null) {
return element;
}
}
return null;
}
protected final Enumeration enumeration;
protected final Mapper mapper;
protected R nextElement;
}