org.springframework.cglib.core.CollectionUtils Maven / Gradle / Ivy
/*
* Copyright 2003,2004 The Apache Software Foundation
*
* Licensed 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
*
* https://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.springframework.cglib.core;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* @author Chris Nokleberg
* @version $Id: CollectionUtils.java,v 1.7 2004/06/24 21:15:21 herbyderby Exp $
*/
@SuppressWarnings({"rawtypes", "unchecked"})
public class CollectionUtils {
private CollectionUtils() { }
public static Map bucket(Collection c, Transformer t) {
Map buckets = new HashMap();
for (Object value : c) {
Object key = t.transform(value);
List bucket = (List)buckets.get(key);
if (bucket == null) {
buckets.put(key, bucket = new LinkedList());
}
bucket.add(value);
}
return buckets;
}
public static void reverse(Map source, Map target) {
for (Object key : source.keySet()) {
target.put(source.get(key), key);
}
}
public static Collection filter(Collection c, Predicate p) {
Iterator it = c.iterator();
while (it.hasNext()) {
if (!p.evaluate(it.next())) {
it.remove();
}
}
return c;
}
public static List transform(Collection c, Transformer t) {
List result = new ArrayList(c.size());
for (Iterator it = c.iterator(); it.hasNext();) {
result.add(t.transform(it.next()));
}
return result;
}
public static Map getIndexMap(List list) {
Map indexes = new HashMap();
int index = 0;
for (Iterator it = list.iterator(); it.hasNext();) {
indexes.put(it.next(), index++);
}
return indexes;
}
}