001: /*
002: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
003: *
004: * This file is part of Resin(R) Open Source
005: *
006: * Each copy or derived work must preserve the copyright notice and this
007: * notice unmodified.
008: *
009: * Resin Open Source is free software; you can redistribute it and/or modify
010: * it under the terms of the GNU General Public License as published by
011: * the Free Software Foundation; either version 2 of the License, or
012: * (at your option) any later version.
013: *
014: * Resin Open Source is distributed in the hope that it will be useful,
015: * but WITHOUT ANY WARRANTY; without even the implied warranty of
016: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
017: * of NON-INFRINGEMENT. See the GNU General Public License for more
018: * details.
019: *
020: * You should have received a copy of the GNU General Public License
021: * along with Resin Open Source; if not, write to the
022: * Free Software Foundation, Inc.
023: * 59 Temple Place, Suite 330
024: * Boston, MA 02111-1307 USA
025: *
026: * @author Scott Ferguson
027: */
028:
029: package com.caucho.amber.expr;
030:
031: import com.caucho.amber.field.AmberField;
032: import com.caucho.amber.field.IdField;
033: import com.caucho.amber.field.KeyManyToOneField;
034: import com.caucho.amber.field.KeyPropertyField;
035: import com.caucho.amber.query.FromItem;
036: import com.caucho.amber.query.QueryParser;
037: import com.caucho.amber.table.Column;
038: import com.caucho.amber.type.EntityType;
039: import com.caucho.util.CharBuffer;
040:
041: /**
042: * Bound identifier expression.
043: */
044: public class KeyManyToOneExpr extends AbstractPathExpr implements
045: IdFieldExpr {
046: private PathExpr _parent;
047: // identifier name value
048: private KeyManyToOneField _manyToOne;
049:
050: private FromItem _fromItem;
051: private FromItem _childFromItem;
052:
053: /**
054: * Creates a new unbound id expression.
055: */
056: public KeyManyToOneExpr(PathExpr parent, KeyManyToOneField manyToOne) {
057: _parent = parent;
058: _manyToOne = manyToOne;
059: }
060:
061: /**
062: * Returns the parent expression.
063: */
064: public PathExpr getParent() {
065: return _parent;
066: }
067:
068: /**
069: * Returns the name.
070: */
071: public IdField getField() {
072: return _manyToOne;
073: }
074:
075: /**
076: * Returns the entity class.
077: */
078: public EntityType getTargetType() {
079: return _manyToOne.getEntityType();
080: }
081:
082: /**
083: * Returns the column.
084: */
085: public Column getColumn() {
086: throw new UnsupportedOperationException();
087: }
088:
089: /**
090: * Creates the expr from the path.
091: */
092: public AmberExpr createField(QueryParser parser, String name) {
093: AmberField field = getTargetType().getField(name);
094:
095: if (field == null)
096: return null;
097: else if (field instanceof IdField) {
098: KeyPropertyField idField = _manyToOne
099: .getIdField((IdField) field);
100:
101: return idField.createExpr(parser, _parent);
102: } else
103: return field.createExpr(parser, this );
104: }
105:
106: /**
107: * Binds the expression as a select item.
108: */
109: public AmberExpr bindSelect(QueryParser parser) {
110: _fromItem = _parent.bindSubPath(parser);
111:
112: return this ;
113: }
114:
115: /**
116: * Return the child from item.
117: */
118: public FromItem getChildFromItem() {
119: return _childFromItem;
120: }
121:
122: /**
123: * Binds the expression as a subpath.
124: */
125: public FromItem bindSubPath(QueryParser parser) {
126: if (_childFromItem != null)
127: return _childFromItem;
128:
129: KeyManyToOneExpr pathExpr = (KeyManyToOneExpr) parser
130: .addPath(this );
131:
132: if (pathExpr != this ) {
133: _fromItem = pathExpr._fromItem;
134: _childFromItem = pathExpr._childFromItem;
135:
136: return _childFromItem;
137: }
138:
139: _fromItem = _parent.bindSubPath(parser);
140:
141: if (_fromItem != null)
142: _childFromItem = _fromItem.getQuery().createFromItem(
143: getTargetType().getTable(),
144: parser.createTableName());
145: else
146: _childFromItem = parser.getSelectQuery().createFromItem(
147: getTargetType().getTable(),
148: parser.createTableName());
149:
150: JoinExpr link = new ManyToOneJoinExpr(_manyToOne
151: .getLinkColumns(), _fromItem, _childFromItem);
152:
153: _childFromItem.setJoinExpr(link);
154:
155: return _childFromItem;
156: }
157:
158: /**
159: * Returns true if the expression uses the from item.
160: */
161: public boolean usesFrom(FromItem from, int type, boolean isNot) {
162: return from == _childFromItem || _parent.usesFrom(from, type);
163: }
164:
165: /**
166: * Replaces linked join to eliminate a table.
167: */
168: /*
169: public AmberExpr replaceJoin(JoinExpr join)
170: {
171: if (_parent instanceof IdExpr) {
172: return join.replace(this);
173: }
174: else
175: return super.replaceJoin(join);
176: }
177: */
178:
179: /**
180: * Returns the table.
181: */
182: /*
183: public String getTable()
184: {
185: if (_childFromItem != null)
186: return _childFromItem.getName();
187: else if (_fromItem != null)
188: return _fromItem.getName();
189: else
190: return _parent.getChildFromItem().getName();
191: }
192: */
193:
194: /**
195: * Generates the where expression.
196: */
197: public void generateMatchArgWhere(CharBuffer cb) {
198: String table;
199:
200: if (_fromItem != null)
201: table = _fromItem.getName();
202: else
203: table = _parent.getChildFromItem().getName();
204:
205: cb.append(_manyToOne.getLinkColumns()
206: .generateMatchArgSQL(table));
207: }
208:
209: public String toString() {
210: return _parent + "." + getField();
211: }
212:
213: public int hashCode() {
214: return 65521 * _parent.hashCode() + getField().hashCode();
215: }
216:
217: public boolean equals(Object o) {
218: if (o == null || !getClass().equals(o.getClass()))
219: return false;
220:
221: KeyManyToOneExpr manyToOne = (KeyManyToOneExpr) o;
222:
223: return (_parent.equals(manyToOne._parent) && getField().equals(
224: manyToOne.getField()));
225: }
226: }
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