001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * // Copyright (c) 1998, 2007, Oracle. All rights reserved.
005: *
006: *
007: * The contents of this file are subject to the terms of either the GNU
008: * General Public License Version 2 only ("GPL") or the Common Development
009: * and Distribution License("CDDL") (collectively, the "License"). You
010: * may not use this file except in compliance with the License. You can obtain
011: * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
012: * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
013: * language governing permissions and limitations under the License.
014: *
015: * When distributing the software, include this License Header Notice in each
016: * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
017: * Sun designates this particular file as subject to the "Classpath" exception
018: * as provided by Sun in the GPL Version 2 section of the License file that
019: * accompanied this code. If applicable, add the following below the License
020: * Header, with the fields enclosed by brackets [] replaced by your own
021: * identifying information: "Portions Copyrighted [year]
022: * [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * If you wish your version of this file to be governed by only the CDDL or
027: * only the GPL Version 2, indicate your decision by adding "[Contributor]
028: * elects to include this software in this distribution under the [CDDL or GPL
029: * Version 2] license." If you don't indicate a single choice of license, a
030: * recipient has the option to distribute your version of this file under
031: * either the CDDL, the GPL Version 2 or to extend the choice of license to
032: * its licensees as provided above. However, if you add GPL Version 2 code
033: * and therefore, elected the GPL Version 2 license, then the option applies
034: * only if the new code is made subject to such option by the copyright
035: * holder.
036: */
037: package oracle.toplink.essentials.internal.parsing;
038:
039: // TopLink imports
040: import oracle.toplink.essentials.expressions.*;
041:
042: /**
043: * INTERNAL
044: * <p><b>Purpose</b>: Used for the EMPTY collection handling
045: * <p><b>Responsibilities</b>:<ul>
046: * <li> Generate the correct expression for an IS EMPTY in EJBQL
047: * </ul>
048: * @author Jon Driscoll and Joel Lucuik
049: * @since August 2003
050: */
051: public class EmptyCollectionComparisonNode extends
052: SimpleConditionalExpressionNode {
053: public boolean notIndicated = false;
054:
055: /**
056: * EmptyCollectionComparisonNode constructor comment.
057: */
058: public EmptyCollectionComparisonNode() {
059: super ();
060: }
061:
062: /**
063: * INTERNAL
064: * Validate node and calculate its type.
065: */
066: public void validate(ParseTreeContext context) {
067: if (left != null) {
068: left.validate(context);
069: }
070: TypeHelper typeHelper = context.getTypeHelper();
071: setType(typeHelper.getBooleanType());
072: }
073:
074: /**
075: * INTERNAL
076: * Return a TopLink expression for this node.
077: */
078: public Expression generateExpression(GenerationContext context) {
079: //get the variable name from the DotNode's right attribute
080: //...WHERE emp.firstName IS EMPTY
081: String emptyAttributeName = ((AttributeNode) getLeft()
082: .getRight()).getAttributeName();
083: Expression whereClause = getLeft().getLeft()
084: .generateExpression(context);
085: if (notIndicated) {
086: return whereClause.notEmpty(emptyAttributeName);
087: } else {
088: return whereClause.isEmpty(emptyAttributeName);
089: }
090: }
091:
092: /**
093: * INTERNAL
094: * Indicate if a NOT was found in the WHERE clause.
095: * Examples:
096: * ...WHERE emp.phoneNumbers IS NOT EMPTY
097: */
098: public void indicateNot() {
099: notIndicated = true;
100: }
101:
102: }
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