SwitchStatement


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   * Switch statement AST node type.
19   * <p>
20   * <pre>
21   * SwitchStatement:
22   *      <b>switch</b> <b>(</b> Expression <b>)</b> 
23   *          <b>{</b> { SwitchCase | Statement } } <b>}</b>
24   * SwitchCase:
25   *      <b>case</b> Expression  <b>:</b>
26   *      <b>default</b> <b>:</b>
27   * </pre>
28   * <code>SwitchCase</code> nodes are treated as a kind of
29   * <code>Statement</code>.
30   * </p>
31   * 
32   * @since 2.0
33   */
34  public class SwitchStatement extends Statement {
35              
36      /**
37       * The "expression" structural property of this node type.
38       * @since 3.0
39       */
40      public static final ChildPropertyDescriptor EXPRESSION_PROPERTY = 
41          new ChildPropertyDescriptor(SwitchStatement.class, "expression", Expression.class, MANDATORY, CYCLE_RISK); //$NON-NLS-1$
42  
43      /**
44       * The "statements" structural property of this node type.
45       * @since 3.0
46       */
47      public static final ChildListPropertyDescriptor STATEMENTS_PROPERTY = 
48          new ChildListPropertyDescriptor(SwitchStatement.class, "statements", Statement.class, CYCLE_RISK); //$NON-NLS-1$
49  
50      /**
51       * A list of property descriptors (element type: 
52       * {@link StructuralPropertyDescriptor}),
53       * or null if uninitialized.
54       */
55      private static final List   PROPERTY_DESCRIPTORS;
56      
57      static {
58          List   propertyList = new ArrayList  (3);
59          createPropertyList(SwitchStatement.class, propertyList);
60          addProperty(EXPRESSION_PROPERTY, propertyList);
61          addProperty(STATEMENTS_PROPERTY, propertyList);
62          PROPERTY_DESCRIPTORS = reapPropertyList(propertyList);
63      }
64  
65      /**
66       * Returns a list of structural property descriptors for this node type.
67       * Clients must not modify the result.
68       * 
69       * @param apiLevel the API level; one of the
70       * <code>AST.JLS*</code> constants
71       * @return a list of property descriptors (element type: 
72       * {@link StructuralPropertyDescriptor})
73       * @since 3.0
74       */
75      public static List   propertyDescriptors(int apiLevel) {
76          return PROPERTY_DESCRIPTORS;
77      }
78              
79      /**
80       * The expression; lazily initialized; defaults to a unspecified, but legal,
81       * expression.
82       */
83      private Expression expression = null;
84  
85      /**
86       * The statements and SwitchCase nodes
87       * (element type: <code>Statement</code>).
88       * Defaults to an empty list.
89       */
90      private ASTNode.NodeList statements =
91          new ASTNode.NodeList(STATEMENTS_PROPERTY);
92      
93      /**
94       * Creates a new unparented switch statement node owned by the given 
95       * AST. By default, the swicth statement has an unspecified, but legal,
96       * expression, and an empty list of switch groups.
97       * <p>
98       * N.B. This constructor is package-private.
99       * </p>
100      * 
101      * @param ast the AST that is to own this node
102      */
103     SwitchStatement(AST ast) {
104         super(ast);
105     }
106 
107     /* (omit javadoc for this method)
108      * Method declared on ASTNode.
109      */
110     final List   internalStructuralPropertiesForType(int apiLevel) {
111         return propertyDescriptors(apiLevel);
112     }
113     
114     /* (omit javadoc for this method)
115      * Method declared on ASTNode.
116      */
117     final ASTNode internalGetSetChildProperty(ChildPropertyDescriptor property, boolean get, ASTNode child) {
118         if (property == EXPRESSION_PROPERTY) {
119             if (get) {
120                 return getExpression();
121             } else {
122                 setExpression((Expression) child);
123                 return null;
124             }
125         }
126         // allow default implementation to flag the error
127         return super.internalGetSetChildProperty(property, get, child);
128     }
129     
130     /* (omit javadoc for this method)
131      * Method declared on ASTNode.
132      */
133     final List   internalGetChildListProperty(ChildListPropertyDescriptor property) {
134         if (property == STATEMENTS_PROPERTY) {
135             return statements();
136         }
137         // allow default implementation to flag the error
138         return super.internalGetChildListProperty(property);
139     }
140     
141     /* (omit javadoc for this method)
142      * Method declared on ASTNode.
143      */
144     final int getNodeType0() {
145         return SWITCH_STATEMENT;
146     }
147 
148     /* (omit javadoc for this method)
149      * Method declared on ASTNode.
150      */
151     ASTNode clone0(AST target) {
152         SwitchStatement result = new SwitchStatement(target);
153         result.setSourceRange(this.getStartPosition(), this.getLength());
154         result.copyLeadingComment(this);
155         result.setExpression((Expression) getExpression().clone(target));
156         result.statements().addAll(ASTNode.copySubtrees(target, statements()));
157         return result;
158     }
159 
160     /* (omit javadoc for this method)
161      * Method declared on ASTNode.
162      */
163     final boolean subtreeMatch0(ASTMatcher matcher, Object   other) {
164         // dispatch to correct overloaded match method
165         return matcher.match(this, other);
166     }
167 
168     /* (omit javadoc for this method)
169      * Method declared on ASTNode.
170      */
171     void accept0(ASTVisitor visitor) {
172         boolean visitChildren = visitor.visit(this);
173         if (visitChildren) {
174             // visit children in normal left to right reading order
175             acceptChild(visitor, getExpression());
176             acceptChildren(visitor, this.statements);
177         }
178         visitor.endVisit(this);
179     }
180     
181     /**
182      * Returns the expression of this switch statement.
183      * 
184      * @return the expression node
185      */ 
186     public Expression getExpression() {
187         if (this.expression == null) {
188             // lazy init must be thread-safe for readers
189             synchronized (this) {
190                 if (this.expression == null) {
191                     preLazyInit();
192                     this.expression = new SimpleName(this.ast);
193                     postLazyInit(this.expression, EXPRESSION_PROPERTY);
194                 }
195             }
196         }
197         return this.expression;
198     }
199         
200     /**
201      * Sets the expression of this switch statement.
202      * 
203      * @param expression the new expression node
204      * @exception IllegalArgumentException if:
205      * <ul>
206      * <li>the node belongs to a different AST</li>
207      * <li>the node already has a parent</li>
208      * <li>a cycle in would be created</li>
209      * </ul>
210      */ 
211     public void setExpression(Expression expression) {
212         if (expression == null) {
213             throw new IllegalArgumentException  ();
214         }
215         ASTNode oldChild = this.expression;
216         preReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
217         this.expression = expression;
218         postReplaceChild(oldChild, expression, EXPRESSION_PROPERTY);
219     }
220     
221     /**
222      * Returns the live ordered list of statements for this switch statement.
223      * Within this list, <code>SwitchCase</code> nodes mark the start of 
224      * the switch groups.
225      * 
226      * @return the live list of statement nodes
227      *    (element type: <code>Statement</code>)
228      */ 
229     public List   statements() {
230         return this.statements;
231     }
232     
233     /* (omit javadoc for this method)
234      * Method declared on ASTNode.
235      */
236     int memSize() {
237         return super.memSize() + 2 * 4;
238     }
239     
240     /* (omit javadoc for this method)
241      * Method declared on ASTNode.
242      */
243     int treeSize() {
244         return
245             memSize()
246             + (this.expression == null ? 0 : getExpression().treeSize())
247             + this.statements.listSize();
248     }
249 }
250
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