View Javadoc

1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License"); 
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License. 
15   *
16   */
17  package org.apache.bcel.generic;
18  
19  import org.apache.bcel.Constants;
20  import org.apache.bcel.Repository;
21  import org.apache.bcel.classfile.JavaClass;
22  
23  /*** 
24   * Denotes reference such as java.lang.String.
25   *
26   * @version $Id: ObjectType.java 386056 2006-03-15 11:31:56Z tcurdt $
27   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
28   */
29  public class ObjectType extends ReferenceType {
30  
31      private String class_name; // Class name of type
32  
33  
34      /***
35       * @param class_name fully qualified class name, e.g. java.lang.String
36       */
37      public ObjectType(String class_name) {
38          super(Constants.T_REFERENCE, "L" + class_name.replace('.', '/') + ";");
39          this.class_name = class_name.replace('/', '.');
40      }
41  
42  
43      /*** @return name of referenced class
44       */
45      public String getClassName() {
46          return class_name;
47      }
48  
49  
50      /*** @return a hash code value for the object.
51       */
52      public int hashCode() {
53          return class_name.hashCode();
54      }
55  
56  
57      /*** @return true if both type objects refer to the same class.
58       */
59      public boolean equals( Object type ) {
60          return (type instanceof ObjectType)
61                  ? ((ObjectType) type).class_name.equals(class_name)
62                  : false;
63      }
64  
65  
66      /***
67       * If "this" doesn't reference a class, it references an interface
68       * or a non-existant entity.
69       * @deprecated this method returns an inaccurate result
70       *   if the class or interface referenced cannot
71       *   be found: use referencesClassExact() instead
72       */
73      public boolean referencesClass() {
74          try {
75              JavaClass jc = Repository.lookupClass(class_name);
76              return jc.isClass();
77          } catch (ClassNotFoundException e) {
78              return false;
79          }
80      }
81  
82  
83      /***
84       * If "this" doesn't reference an interface, it references a class
85       * or a non-existant entity.
86       * @deprecated this method returns an inaccurate result
87       *   if the class or interface referenced cannot
88       *   be found: use referencesInterfaceExact() instead
89       */
90      public boolean referencesInterface() {
91          try {
92              JavaClass jc = Repository.lookupClass(class_name);
93              return !jc.isClass();
94          } catch (ClassNotFoundException e) {
95              return false;
96          }
97      }
98  
99  
100     /***
101      * Return true if this type references a class,
102      * false if it references an interface.
103      * @return true if the type references a class, false if
104      *   it references an interface
105      * @throws ClassNotFoundException if the class or interface
106      *   referenced by this type can't be found
107      */
108     public boolean referencesClassExact() throws ClassNotFoundException {
109         JavaClass jc = Repository.lookupClass(class_name);
110         return jc.isClass();
111     }
112 
113 
114     /***
115      * Return true if this type references an interface,
116      * false if it references a class.
117      * @return true if the type references an interface, false if
118      *   it references a class
119      * @throws ClassNotFoundException if the class or interface
120      *   referenced by this type can't be found
121      */
122     public boolean referencesInterfaceExact() throws ClassNotFoundException {
123         JavaClass jc = Repository.lookupClass(class_name);
124         return !jc.isClass();
125     }
126 
127 
128     /***
129      * Return true if this type is a subclass of given ObjectType.
130      * @throws ClassNotFoundException if any of this class's superclasses
131      *  can't be found
132      */
133     public boolean subclassOf( ObjectType superclass ) throws ClassNotFoundException {
134         if (this.referencesInterface() || superclass.referencesInterface()) {
135             return false;
136         }
137         return Repository.instanceOf(this.class_name, superclass.class_name);
138     }
139 
140 
141     /***
142      * Java Virtual Machine Specification edition 2, ß 5.4.4 Access Control
143      * @throws ClassNotFoundException if the class referenced by this type
144      *   can't be found
145      */
146     public boolean accessibleTo( ObjectType accessor ) throws ClassNotFoundException {
147         JavaClass jc = Repository.lookupClass(class_name);
148         if (jc.isPublic()) {
149             return true;
150         } else {
151             JavaClass acc = Repository.lookupClass(accessor.class_name);
152             return acc.getPackageName().equals(jc.getPackageName());
153         }
154     }
155 }