Java Collection Flatten flatten(Collection l)

Description

flatten

License

Apache License

Declaration

@SuppressWarnings({ "unchecked", "rawtypes" })
    public static List<?> flatten(Collection<?> l) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2012 Apigee Corporation/*from  w  ww.  ja v a2  s  .  co  m*/
 * 
 * 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
 * 
 *   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.
 ******************************************************************************/

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

public class Main {
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static List<?> flatten(Collection<?> l) {
        boolean hasCollection = false;
        for (Object o : l) {
            if (o instanceof Collection) {
                hasCollection = true;
                break;
            }
        }
        if (!hasCollection && (l instanceof List)) {
            return (List<?>) l;
        }
        List newList = new ArrayList();
        for (Object o : l) {
            if (o instanceof List) {
                newList.addAll(flatten((List) o));
            } else {
                newList.add(o);
            }
        }
        return newList;
    }
}

Related

1. flatten( Collection colOfCols)
2. flatten(Class cls, Collection> collections)
3. flatten(Collection> collections)
4. flatten(Collection> cols)
5. flatten(Collection list, Class type)
6. flatten(Collection> nestedList)
7. flatten(Collection> collOfLists)
8. flatten(Collection collection, char separator)