FieldExpr


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
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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 SoftwareFoundation, Inc.
23   *   59 Temple Place, Suite 330
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25   *
26   * @author Scott Ferguson
27   */
28  
29  package com.caucho.ejb.ql;
30  
31  import com.caucho.config.ConfigException;
32  import com.caucho.ejb.cfg.CmpField;
33  import com.caucho.ejb.cfg.CmpRelation;
34  import com.caucho.ejb.cfg.EjbEntityBean;
35  import com.caucho.util.CharBuffer;
36  
37  /**
38   * Expression representing a field or a relation.
39   */
40  class FieldExpr extends Expr {
41    // base expression
42    private PathExpr _base;
43    // field name
44    private String   _name;
45  
46    // bean information
47    private EjbEntityBean _bean;
48    // field information
49    private CmpField _field;
50    // relation information
51    private CmpRelation _relation;
52    
53    // SQL id for the results of this field
54    private String   _tableId;
55    // base id if special
56    private String   _baseId;
57    // sql field
58    private String   _sqlField;
59  
60    private int _primaryKeyFieldIndex;
61  
62    // use count
63    private int _useCount;
64    private boolean _hasRelation;
65  
66    /**
67     * Creates a new field expression.
68     *
69     * @param base the base expression
70     * @param field name of the field
71     */
72    FieldExpr(Query query, PathExpr base,
73              String   fieldName, CmpField field)
74      throws ConfigException
75    {
76      _query = query;
77      _base = base;
78      _name = fieldName;
79  
80      _field = field;
81  
82      /*
83      PrimaryKey key = base.getItemBean().getPrimaryKey();
84      _primaryKeyFieldIndex = key.indexOf(field);
85      if (_primaryKeyFieldIndex < 0)
86        base.setUsesField();
87      */
88  
89      setJavaType(field.getJavaType());
90    }
91  
92    boolean hasRelation()
93    {
94      return _hasRelation;
95    }
96  
97    void setRelation()
98    {
99      _hasRelation = true;
100   }
101 
102   /**
103    * Returns the base expression
104    */
105   Expr getBase()
106   {
107     return _base;
108   }
109 
110   /**
111    * Returns the field name
112    */
113   String   getField()
114   {
115     return _name;
116   }
117 
118   /**
119    * Returns the bean type of the result object
120    */
121   EjbEntityBean getBean()
122   {
123     return _bean;
124   }
125 
126   /**
127    * Returns the relation
128    */
129   CmpRelation getRelation()
130   {
131     return _relation;
132   }
133 
134   /**
135    * Returns the SQL table identifier for the result of the field expression.
136    */
137   String   getTableId()
138   {
139     return _tableId;
140   }
141 
142   /**
143    * Sets the SQL table identifier for the result of the field expression.
144    */
145   void setTableId(String   tableId)
146   {
147     _tableId = tableId;
148   }
149 
150   /**
151    * Returns the SQL id for the base 
152    */
153   String   getBaseId()
154   {
155     return _base.getTable();
156   }
157 
158   /**
159    * Returns the SQL field reference.
160    */
161   String   getSQLField()
162   {
163     /*
164     if (_sqlField != null)
165       return _sqlField;
166     else if (_field != null)
167       return _field.getSQLName();
168     else if (_relation != null)
169       return _relation.getTargetSQLPrefix();
170     else
171       return PersistentBean.javaToSQLName(_name);
172     */
173     throw new UnsupportedOperationException  ();
174   }
175 
176   void decrementUse()
177   {
178     _useCount--;
179   }
180 
181   int getUseCount()
182   {
183     return _useCount;
184   }
185 
186   /**
187    * For collections, returns the underlying item bean.
188    */
189   EjbEntityBean getItemBean()
190   {
191     return _bean;
192   }
193 
194   /*
195   int getComponentCount()
196   {
197     if (isPrimaryKeyField)
198       return base.getComponentCount();
199 
200     return super.getComponentCount();
201   }
202   */
203 
204   /**
205    * Prints the select SQL for this expression
206    *
207    * @param gen the java code generator
208    */
209     /*
210   void generateSelect(CharBuffer cb)
211   {
212     if (_primaryKeyFieldIndex >= 0) {
213       _base.printComponent(cb, _primaryKeyFieldIndex);
214       return;
215     }
216 
217     if (_query.getFromList().size() == 1) {
218       // special case to handle strange databases
219       cb.append(_field.getSQLName());
220     }
221     else {
222       cb.append(_base.getTable());
223       cb.append(".");
224       cb.append(_field.getSQLName());
225     }
226     throw new UnsupportedOperationException();
227   }
228     */
229 
230   /**
231    * Prints the select SQL for this expression
232    *
233    * @param gen the java code generator
234    */
235   String   getSelectTable(CharBuffer cb)
236     throws ConfigException
237   {
238     /*
239     if (_query.getFromList().size() == 1) {
240       // special case to handle strange databases
241       return null;
242     }
243     else
244       return _base.getTable();
245     */
246     return _base.getTable();
247   }
248 
249   /**
250    * Prints the where SQL for this expression
251    *
252    * @param gen the java code generator
253    */
254   void generateWhere(CharBuffer cb)
255   {
256     /*
257     if (_primaryKeyFieldIndex >= 0) {
258       _base.generateComponent(cb, _primaryKeyFieldIndex);
259       return;
260     }
261     */
262 
263       /*
264     if (_query.getFromList().size() == 1) {
265       // special case to handle strange databases
266       cb.append(_field.getSQLName());
267     }
268     else {
269       cb.append(_base.getTable());
270       cb.append(".");
271       cb.append(_field.getSQLName());
272     }
273       */
274 
275     _base.generateWhere(cb);
276     cb.append(".");
277     cb.append(_name);
278   }
279 
280   /*
281   void generateComponent(CharBuffer cb, int i)
282   {
283     if (_primaryKeyFieldIndex >= 0) {
284       _base.generateComponent(cb, i);
285       return;
286     }
287 
288     super.generateComponent(cb, i);
289   }
290   */
291 
292   /**
293    * Returns true if the two expressions are equal
294    */
295   public boolean equals(Object   bObj)
296   {
297     if (! (bObj instanceof FieldExpr))
298       return false;
299 
300     FieldExpr b = (FieldExpr) bObj;
301 
302     return _field.equals(b._field) && _base.equals(b._base);
303   }
304 
305   /**
306    * Returns a hash code for the field
307    */
308   public int hashCode()
309   {
310     return _name.hashCode() * 65521 + _base.hashCode();
311   }
312 
313   public String   toString()
314   {
315     return _base.toString() + "." + _name;
316   }
317 }
318
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