ReturnStatement


1   /*******************************************************************************
2    * Copyright (c) 2000, 2004 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  
12  package org.eclipse.jdt.core.dom;
13  
14  import java.util.ArrayList  ;
15  import java.util.List  ;
16  
17  /**
18   * Return statement AST node type.
19   *
20   * <pre>
21   * ReturnStatement:
22   *    <b>return</b> [ Expression ] <b>;</b>
23   * </pre>
24   * 
25   * @since 2.0
26   */
27  public class ReturnStatement extends Statement {
28              
29      /**
30       * The "expression" structural property of this node type.
31       * @since 3.0
32       */
33      public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = 
34          new ChildPropertyDescriptor(ReturnStatement.class, "expression", Expression.class, OPTIONAL, CYCLE_RISK); //$NON-NLS-1$
35  
36      /**
37       * A list of property descriptors (element type: 
38       * {@link StructuralPropertyDescriptor}),
39       * or null if uninitialized.
40       */
41      private static final List   PROPERTY_DESCRIPTORS;
42      
43      static {
44          List   propertyList = new ArrayList  (2);
45          createPropertyList(ReturnStatement.class, propertyList);
46          addProperty(EXPRESSION_PROPERTY, propertyList);
47          PROPERTY_DESCRIPTORS = reapPropertyList(propertyList);
48      }
49  
50      /**
51       * Returns a list of structural property descriptors for this node type.
52       * Clients must not modify the result.
53       * 
54       * @param apiLevel the API level; one of the
55       * <code>AST.JLS&ast;</code> constants
56       * @return a list of property descriptors (element type: 
57       * {@link StructuralPropertyDescriptor})
58       * @since 3.0
59       */
60      public static List   propertyDescriptors(int apiLevel) {
61          return PROPERTY_DESCRIPTORS;
62      }
63              
64      /**
65       * The expression; <code>null</code> for none; defaults to none.
66       */
67      private Expression optionalExpression = null;
68      
69      /**
70       * Creates a new AST node for a return statement owned by the 
71       * given AST. By default, the statement has no expression.
72       * 
73       * @param ast the AST that is to own this node
74       */
75      ReturnStatement(AST ast) {
76          super(ast);
77      }
78  
79      /* (omit javadoc for this method)
80       * Method declared on ASTNode.
81       */
82      final List   internalStructuralPropertiesForType(int apiLevel) {
83          return propertyDescriptors(apiLevel);
84      }
85      
86      /* (omit javadoc for this method)
87       * Method declared on ASTNode.
88       */
89      final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
90          if (property == EXPRESSION_PROPERTY) {
91              if (get) {
92                  return getExpression();
93              } else {
94                  setExpression((Expression) child);
95                  return null;
96              }
97          }
98          // allow default implementation to flag the error
99          return super.internalGetSetChildProperty(property, get, child);
100     }
101     
102     /* (omit javadoc for this method)
103      * Method declared on ASTNode.
104      */
105     final int getNodeType0() {
106         return RETURN_STATEMENT;
107     }
108 
109     /* (omit javadoc for this method)
110      * Method declared on ASTNode.
111      */
112     ASTNode clone0(AST target) {
113         ReturnStatement result = new ReturnStatement(target);
114         result.setSourceRange(this.getStartPosition(), this.getLength());
115         result.copyLeadingComment(this);
116         result.setExpression(
117             (Expression) ASTNode.copySubtree(target, getExpression()));
118         return result;
119     }
120 
121     /* (omit javadoc for this method)
122      * Method declared on ASTNode.
123      */
124     final boolean subtreeMatch0(ASTMatcher matcher, Object   other) {
125         // dispatch to correct overloaded match method
126         return matcher.match(this, other);
127     }
128 
129     /* (omit javadoc for this method)
130      * Method declared on ASTNode.
131      */
132     void accept0(ASTVisitor visitor) {
133         boolean visitChildren = visitor.visit(this);
134         if (visitChildren) {
135             acceptChild(visitor, getExpression());
136         }
137         visitor.endVisit(this);
138     }
139     
140     /**
141      * Returns the expression of this return statement, or 
142      * <code>null</code> if there is none.
143      * 
144      * @return the expression node, or <code>null</code> if there is none
145      */ 
146     public Expression getExpression() {
147         return this.optionalExpression;
148     }
149     
150     /**
151      * Sets or clears the expression of this return statement.
152      * 
153      * @param expression the expression node, or <code>null</code> if 
154      *    there is none
155      * @exception IllegalArgumentException if:
156      * <ul>
157      * <li>the node belongs to a different AST</li>
158      * <li>the node already has a parent</li>
159      * <li>a cycle in would be created</li>
160      * </ul>
161      */ 
162     public void setExpression(Expression expression) {
163         ASTNode oldChild = this.optionalExpression;
164         preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
165         this.optionalExpression = expression;
166         postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
167     }
168     
169     /* (omit javadoc for this method)
170      * Method declared on ASTNode.
171      */
172     int memSize() {
173         return super.memSize() + 1 * 4;
174     }
175     
176     /* (omit javadoc for this method)
177      * Method declared on ASTNode.
178      */
179     int treeSize() {
180         return
181             memSize()
182             + (this.optionalExpression == null ? 0 : getExpression().treeSize());
183     }
184 }
185 
186
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