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1   /*
2    * ModeShape (http://www.modeshape.org)
3    * See the COPYRIGHT.txt file distributed with this work for information
4    * regarding copyright ownership.  Some portions may be licensed
5    * to Red Hat, Inc. under one or more contributor license agreements.
6    * See the AUTHORS.txt file in the distribution for a full listing of 
7    * individual contributors.
8    *
9    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
10   * is licensed to you under the terms of the GNU Lesser General Public License as
11   * published by the Free Software Foundation; either version 2.1 of
12   * the License, or (at your option) any later version.
13   * 
14   * ModeShape is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17   * Lesser General Public License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this software; if not, write to the Free
21   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23   */
24  package org.modeshape.graph.query.process;
25  
26  import java.util.ArrayList;
27  import java.util.Collections;
28  import java.util.List;
29  import org.modeshape.graph.query.QueryContext;
30  import org.modeshape.graph.query.QueryResults.Columns;
31  
32  /**
33   */
34  public class UnionComponent extends SetOperationComponent {
35  
36      public UnionComponent( QueryContext context,
37                             Columns columns,
38                             Iterable<ProcessingComponent> sources,
39                             boolean alreadySorted,
40                             boolean all ) {
41          super(context, columns, sources, alreadySorted, all);
42      }
43  
44      /**
45       * {@inheritDoc}
46       * 
47       * @see org.modeshape.graph.query.process.ProcessingComponent#execute()
48       */
49      @Override
50      public List<Object[]> execute() {
51          List<Object[]> tuples = new ArrayList<Object[]>();
52          for (ProcessingComponent source : sources()) {
53              List<Object[]> results = source.execute();
54              tuples.addAll(results);
55          }
56          if (removeDuplicatesComparator != null) {
57              Collections.sort(tuples, this.removeDuplicatesComparator);
58              removeDuplicatesIfRequested(tuples);
59          }
60          return tuples;
61      }
62  }