AmberExpr


1   /*
2    * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3    *
4    * This file is part of Resin(R) Open Source
5    *
6    * Each copy or derived work must preserve the copyright notice and this
7    * notice unmodified.
8    *
9    * Resin Open Source is free software; you can redistribute it and/or modify
10   * it under the terms of the GNU General Public License as published by
11   * the Free Software Foundation; either version 2 of the License, or
12   * (at your option) any later version.
13   *
14   * Resin Open Source 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, or any warranty
17   * of NON-INFRINGEMENT.  See the GNU General Public License for more
18   * details.
19   *
20   * You should have received a copy of the GNU General Public License
21   * along with Resin Open Source; if not, write to the
22   *   Free Software Foundation, Inc.
23   *   59 Temple Place, Suite 330
24   *   Boston, MA 02111-1307  USA
25   *
26   * @author Scott Ferguson
27   */
28  
29  package com.caucho.amber.expr;
30  
31  import com.caucho.amber.entity.EntityItem;
32  import com.caucho.amber.manager.AmberConnection;
33  import com.caucho.amber.query.FromItem;
34  import com.caucho.amber.query.QueryParseException;
35  import com.caucho.amber.query.QueryParser;
36  import com.caucho.amber.type.Type;
37  import com.caucho.util.CharBuffer;
38  
39  import java.sql.ResultSet  ;
40  import java.sql.SQLException  ;
41  
42  /**
43   * Represents an Amber query expression
44   */
45  public interface AmberExpr {
46    public final static int USES_DATA = 0;
47    public final static int IS_INNER_JOIN = 1;
48  
49    /**
50     * Returns true for a boolean expression.
51     */
52    boolean isBoolean();
53  
54    /**
55     * Returns the expr type.
56     */
57    Type getType();
58  
59    /**
60     * Binds the expression as a select item.
61     */
62    AmberExpr bindSelect(QueryParser parser);
63  
64    /**
65     * Returns true if the expression uses the from item.
66     */
67    boolean usesFrom(FromItem from, int type);
68  
69    /**
70     * Returns true if the expression uses the from item.
71     */
72    boolean usesFrom(FromItem from, int type, boolean isNot);
73  
74    /**
75     * Returns true if the item is required to exist by the expression, e.g.
76     * foo.id='1' forces foo to exist.
77     */
78    boolean exists(FromItem from);
79  
80    /**
81     * Returns true if the expression item is required to exist, e.g.
82     * constants and arguments.
83     *
84     * (Can also apply to arguments required to exist after a particular
85     * from item, i.e. from items already proved to exist.)
86     */
87    boolean exists();
88  
89    /**
90     * Returns true if the expression uses the from item.
91     */
92    AmberExpr replaceJoin(JoinExpr join);
93  
94    /**
95     * Generates the where expression.
96     */
97    void generateWhere(CharBuffer cb);
98  
99    /**
100    * Generates the (update) where expression.
101    */
102   void generateUpdateWhere(CharBuffer cb);
103 
104   /**
105    * Generates the having expression.
106    */
107   void generateHaving(CharBuffer cb);
108 
109   /**
110    * Generates the where expression.
111    */
112   void generateJoin(CharBuffer cb);
113 
114   /**
115    * Generates the select expression.
116    */
117   void generateSelect(CharBuffer cb);
118 
119   /**
120    * Converts to a boolean expression.
121    */
122   public AmberExpr createBoolean()
123     throws QueryParseException;
124 
125   /**
126    * Returns the object for the expr.
127    */
128   public Object   getObject(AmberConnection aConn, ResultSet   rs, int index)
129     throws SQLException  ;
130 
131   /**
132    * Returns the cache object for the expr.
133    */
134   public Object   getCacheObject(AmberConnection aConn,
135                                ResultSet   rs, int index)
136     throws SQLException  ;
137 
138   /**
139    * Returns the object for the expr.
140    */
141   public EntityItem findItem(AmberConnection aConn,
142                              ResultSet   rs, int index)
143     throws SQLException  ;
144 }
145
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