Java Collection Merge mergeCollection(Collection a, Collection b)

Description

merge Collection

License

Apache License

Declaration

@SuppressWarnings("unchecked")
    public static <O> Collection<O> mergeCollection(Collection<O> a, Collection<O> b) 

Method Source Code

//package com.java2s;
/*//  w  w  w.ja  v  a2s . co m
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.Collection;

public class Main {
    @SuppressWarnings("unchecked")
    public static <O> Collection<O> mergeCollection(Collection<O> a, Collection<O> b) {
        if (a == null && b == null)
            return null;
        Collection<O> result = null;
        try {
            if (a != null)
                result = a.getClass().newInstance();
            else
                result = b.getClass().newInstance();
        } catch (Exception e) {
            // Shall not happen
        }
        if (a == null) {
            result.addAll(b);
        } else if (b == null) {
            result.addAll(a);
        } else {
            result.addAll(a);
            for (O o : b) {
                if (!result.contains(o)) {
                    result.add(o);
                }
            }
        }

        return result;
    }
}

Related

1. merge(Collection... elems)
2. merge(final Collection values)
3. merge(J just, Collection justs)
4. mergeArrayIntoCollection(T[] array, Collection collection)
5. mergeCollection( final Collection col1, final Collection col2)
6. mergeCollections(Collection... inCollections)