DoStatement


1   /*******************************************************************************
2    * Copyright (c) 2000, 2006 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   * Do statement AST node type.
19   *
20   * <pre>
21   * DoStatement:
22   *    <b>do</b> Statement <b>while</b> <b>(</b> Expression <b>)</b> <b>;</b>
23   * </pre>
24   * 
25   * @since 2.0
26   */
27  public class DoStatement 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(DoStatement.class, "expression", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
35  
36      /**
37       * The "body" structural property of this node type.
38       * @since 3.0
39       */
40      public static final ChildPropertyDescriptor BODY_PROPERTY = 
41          new ChildPropertyDescriptor(DoStatement.class, "body", Statement.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
42  
43      /**
44       * A list of property descriptors (element type: 
45       * {@link StructuralPropertyDescriptor}),
46       * or null if uninitialized.
47       */
48      private static final List   PROPERTY_DESCRIPTORS;
49      
50      static {
51          List   properyList = new ArrayList  (3);
52          createPropertyList(DoStatement.class, properyList);
53          addProperty(EXPRESSION_PROPERTY, properyList);
54          addProperty(BODY_PROPERTY, properyList);
55          PROPERTY_DESCRIPTORS = reapPropertyList(properyList);
56      }
57  
58      /**
59       * Returns a list of structural property descriptors for this node type.
60       * Clients must not modify the result.
61       * 
62       * @param apiLevel the API level; one of the
63       * <code>AST.JLS*</code> constants
64  
65       * @return a list of property descriptors (element type: 
66       * {@link StructuralPropertyDescriptor})
67       * @since 3.0
68       */
69      public static List   propertyDescriptors(int apiLevel) {
70          return PROPERTY_DESCRIPTORS;
71      }
72              
73      /**
74       * The expression; lazily initialized; defaults to an unspecified, but 
75       * legal, expression.
76       */
77      private Expression expression = null;
78  
79      /**
80       * The body statement; lazily initialized; defaults to an empty block.
81       */
82      private Statement body = null;
83  
84      /**
85       * Creates a new unparented do statement node owned by the given 
86       * AST. By default, the expresssion is unspecified, but legal,
87       * and the body statement is an empty block.
88       * <p>
89       * N.B. This constructor is package-private.
90       * </p>
91       * 
92       * @param ast the AST that is to own this node
93       */
94      DoStatement(AST ast) {
95          super(ast);
96      }
97  
98      /* (omit javadoc for this method)
99       * Method declared on ASTNode.
100      */
101     final List   internalStructuralPropertiesForType(int apiLevel) {
102         return propertyDescriptors(apiLevel);
103     }
104     
105     /* (omit javadoc for this method)
106      * Method declared on ASTNode.
107      */
108     final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
109         if (property == EXPRESSION_PROPERTY) {
110             if (get) {
111                 return getExpression();
112             } else {
113                 setExpression((Expression) child);
114                 return null;
115             }
116         }
117         if (property == BODY_PROPERTY) {
118             if (get) {
119                 return getBody();
120             } else {
121                 setBody((Statement) child);
122                 return null;
123             }
124         }
125         // allow default implementation to flag the error
126         return super.internalGetSetChildProperty(property, get, child);
127     }
128     
129     /* (omit javadoc for this method)
130      * Method declared on ASTNode.
131      */
132     final int getNodeType0() {
133         return DO_STATEMENT;
134     }
135 
136     /* (omit javadoc for this method)
137      * Method declared on ASTNode.
138      */
139     ASTNode clone0(AST target) {
140         DoStatement result = new DoStatement(target);
141         result.setSourceRange(this.getStartPosition(), this.getLength());
142         result.copyLeadingComment(this);
143         result.setExpression((Expression) getExpression().clone(target));
144         result.setBody((Statement) getBody().clone(target));
145         return result;
146     }
147 
148     /* (omit javadoc for this method)
149      * Method declared on ASTNode.
150      */
151     final boolean subtreeMatch0(ASTMatcher matcher, Object   other) {
152         // dispatch to correct overloaded match method
153         return matcher.match(this, other);
154     }
155 
156     /* (omit javadoc for this method)
157      * Method declared on ASTNode.
158      */
159     void accept0(ASTVisitor visitor) {
160         boolean visitChildren = visitor.visit(this);
161         if (visitChildren) {
162             // visit children in normal left to right reading order
163             acceptChild(visitor, getBody());
164             acceptChild(visitor, getExpression());
165         }
166         visitor.endVisit(this);
167     }
168     
169     /**
170      * Returns the expression of this do statement.
171      * 
172      * @return the expression node
173      */ 
174     public Expression getExpression() {
175         if (this.expression == null) {
176             // lazy init must be thread-safe for readers
177             synchronized (this) {
178                 if (this.expression == null) {
179                     preLazyInit();
180                     this.expression = new SimpleName(this.ast);
181                     postLazyInit(this.expression, EXPRESSION_PROPERTY);
182                 }
183             }
184         }
185         return this.expression;
186     }
187     
188     /**
189      * Sets the expression of this do statement.
190      * 
191      * @param expression the expression node
192      * @exception IllegalArgumentException if:
193      * <ul>
194      * <li>the node belongs to a different AST</li>
195      * <li>the node already has a parent</li>
196      * <li>a cycle in would be created</li>
197      * </ul>
198      */ 
199     public void setExpression(Expression expression) {
200         if (expression == null) {
201             throw new IllegalArgumentException  ();
202         }
203         ASTNode oldChild = this.expression;
204         preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
205         this.expression = expression;
206         postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
207     }
208 
209     /**
210      * Returns the body of this do statement.
211      * 
212      * @return the body statement node
213      */ 
214     public Statement getBody() {
215         if (this.body == null) {
216             // lazy init must be thread-safe for readers
217             synchronized (this) {
218                 if (this.body == null) {
219                     preLazyInit();
220                     this.body = new Block(this.ast);
221                     postLazyInit(this.body, BODY_PROPERTY);
222                 }
223             }
224         }
225         return this.body;
226     }
227     
228     /**
229      * Sets the body of this do statement.
230      * <p>
231      * Special note: The Java language does not allow a local variable declaration
232      * to appear as the body of a do statement (they may only appear within a
233      * block). However, the AST will allow a <code>VariableDeclarationStatement</code>
234      * as the body of a <code>DoStatement</code>. To get something that will
235      * compile, be sure to embed the <code>VariableDeclarationStatement</code>
236      * inside a <code>Block</code>.
237      * </p>
238      * 
239      * @param statement the body statement node
240      * @exception IllegalArgumentException if:
241      * <ul>
242      * <li>the node belongs to a different AST</li>
243      * <li>the node already has a parent</li>
244      * <li>a cycle in would be created</li>
245      * </ul>
246      */ 
247     public void setBody(Statement statement) {
248         if (statement == null) {
249             throw new IllegalArgumentException  ();
250         }
251         ASTNode oldChild = this.body;
252         preReplaceChild(oldChild, statement, BODY_PROPERTY);
253         this.body = statement;
254         postReplaceChild(oldChild, statement, BODY_PROPERTY);
255     }
256     
257     /* (omit javadoc for this method)
258      * Method declared on ASTNode.
259      */
260     int memSize() {
261         return super.memSize() + 2 * 4;
262     }
263     
264     /* (omit javadoc for this method)
265      * Method declared on ASTNode.
266      */
267     int treeSize() {
268         return
269             memSize()
270             + (this.expression == null ? 0 : getExpression().treeSize())
271             + (this.body == null ? 0 : getBody().treeSize());
272     }
273 }
274
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