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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.model;
25  
26  import java.util.Collections;
27  import java.util.HashMap;
28  import java.util.Map;
29  import org.modeshape.common.util.CheckArg;
30  
31  public enum JoinType implements Readable {
32      INNER("INNER JOIN"),
33      LEFT_OUTER("LEFT OUTER JOIN"),
34      RIGHT_OUTER("RIGHT OUTER JOIN"),
35      FULL_OUTER("FULL OUTER JOIN"),
36      CROSS("CROSS JOIN");
37  
38      private static final Map<String, JoinType> TYPE_BY_SYMBOL;
39      static {
40          Map<String, JoinType> typesBySymbol = new HashMap<String, JoinType>();
41          for (JoinType type : JoinType.values()) {
42              typesBySymbol.put(type.getSymbol().toUpperCase(), type);
43          }
44          TYPE_BY_SYMBOL = Collections.unmodifiableMap(typesBySymbol);
45      }
46  
47      private final String symbol;
48  
49      private JoinType( String symbol ) {
50          this.symbol = symbol;
51      }
52  
53      /**
54       * @return symbol
55       */
56      public String getSymbol() {
57          return symbol;
58      }
59  
60      /**
61       * Check if this join type is an outer join.
62       * 
63       * @return true if left/right/full outer, or false otherwise
64       */
65      public boolean isOuter() {
66          return this.equals(LEFT_OUTER) || this.equals(FULL_OUTER) || this.equals(RIGHT_OUTER);
67      }
68  
69      /**
70       * {@inheritDoc}
71       * 
72       * @see java.lang.Enum#toString()
73       */
74      @Override
75      public String toString() {
76          return symbol;
77      }
78  
79      /**
80       * Attempt to find the JoinType given a symbol. The matching is done independent of case.
81       * 
82       * @param symbol the symbol
83       * @return the JoinType having the supplied symbol, or null if there is no JoinType with the supplied symbol
84       * @throws IllegalArgumentException if the symbol is null
85       */
86      public static JoinType forSymbol( String symbol ) {
87          CheckArg.isNotNull(symbol, "symbol");
88          return TYPE_BY_SYMBOL.get(symbol.toUpperCase());
89      }
90  
91      /**
92       * {@inheritDoc}
93       * 
94       * @see org.modeshape.graph.query.model.Readable#getString()
95       */
96      public String getString() {
97          return getSymbol();
98      }
99  }