StructuralPropertyDescriptor


1   /*******************************************************************************
2    * Copyright (c) 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  package org.eclipse.jdt.core.dom;
12  
13  /**
14   * Abstract base class for property descriptors of AST nodes.
15   * There are three kinds of properties:
16   * <ul>
17   * <li>simple properties ({@link SimplePropertyDescriptor})
18   * - properties where the value is a primitive (int, boolean)
19   * or simple (String, InfixExprsssion.Operator) type other than an
20   * AST node; for example, the identifier of a {@link SimpleName}</li>
21   * <li>child properties ({@link ChildPropertyDescriptor})
22   * - properties whose value is another AST node;
23   * for example, the name of a {@link MethodDeclaration}</li>
24   * <li>child list properties ({@link ChildListPropertyDescriptor})
25   * - properties where the value is a list of AST nodes;
26   * for example, the statements of a {@link Block}</li>
27   * </ul>
28   * 
29   * @since 3.0
30   */
31  public abstract class StructuralPropertyDescriptor {
32      
33      /**
34       * Property id.
35       */
36      private final String   propertyId;
37      
38      /**
39       * The concrete AST node type that owns this property.
40       */
41      private final Class   nodeClass;
42      
43      /**
44       * Creates a new property descriptor for the given node type
45       * with the given property id.
46       * Note that this constructor is declared package-private so that
47       * property descriptors can only be created by the AST
48       * implementation.
49       * 
50       * @param nodeClass concrete AST node type that owns this property
51       * @param propertyId the property id
52       */
53      StructuralPropertyDescriptor(Class   nodeClass, String   propertyId) {
54          if (nodeClass == null || propertyId == null) {
55              throw new IllegalArgumentException  ();
56          }
57          this.propertyId = propertyId;
58          this.nodeClass = nodeClass;
59      }
60      
61      /**
62       * Returns the id of this property.
63       * 
64       * @return the property id
65       */
66      public final String   getId() {
67          return this.propertyId;
68      }
69      
70      /**
71       * Returns the AST node type that owns this property.
72       * <p>
73       * For example, for all properties of the node type
74       * TypeDeclaration, this method returns <code>TypeDeclaration.class</code>.
75       * </p>
76       * 
77       * @return the node type that owns this property
78       */
79      public final Class   getNodeClass() {
80          return this.nodeClass;
81      }
82      
83      /**
84       * Returns whether this property is a simple property
85       * (instance of {@link SimplePropertyDescriptor}.
86       * 
87       * @return <code>true</code> if this is a simple property, and 
88       * <code>false</code> otherwise
89       */
90      public final boolean isSimpleProperty(){
91          return (this instanceof SimplePropertyDescriptor);
92      }
93      
94      /**
95       * Returns whether this property is a child property
96       * (instance of {@link ChildPropertyDescriptor}.
97       * 
98       * @return <code>true</code> if this is a child property, and 
99       * <code>false</code> otherwise
100      */
101     public final boolean isChildProperty() {
102         return (this instanceof ChildPropertyDescriptor);
103     }
104     
105     /**
106      * Returns whether this property is a child list property
107      * (instance of {@link ChildListPropertyDescriptor}.
108      * 
109      * @return <code>true</code> if this is a child list property, and 
110      * <code>false</code> otherwise
111      */
112     public final boolean isChildListProperty() { 
113         return (this instanceof ChildListPropertyDescriptor);
114     }
115 
116     /**
117      * Returns a string suitable for debug purposes.
118      * @return {@inheritDoc}
119      */
120     public String   toString() {
121         StringBuffer   b = new StringBuffer  ();
122         if (isChildListProperty()) {
123             b.append("ChildList"); //$NON-NLS-1$
124         }
125         if (isChildProperty()) {
126             b.append("Child"); //$NON-NLS-1$
127         }
128         if (isSimpleProperty()) {
129             b.append("Simple"); //$NON-NLS-1$
130         }
131         b.append("Property["); //$NON-NLS-1$
132         if (this.nodeClass != null) {
133             b.append(this.nodeClass.getName());
134         }
135         b.append(","); //$NON-NLS-1$
136         if (this.propertyId != null) {
137             b.append(this.propertyId);
138         }
139         b.append("]"); //$NON-NLS-1$
140         return b.toString();
141     }
142 }
143
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