001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.bcel.generic;
018
019import org.apache.bcel.Const;
020import org.apache.bcel.Repository;
021import org.apache.bcel.classfile.JavaClass;
022import org.apache.bcel.classfile.Utility;
023
024/**
025 * Denotes reference such as {@link String}.
026 */
027public class ObjectType extends ReferenceType {
028
029    /**
030     * Constructs a new instance.
031     *
032     * @param className fully qualified class name, e.g. java.lang.String
033     * @return a new instance.
034     * @since 6.0
035     */
036    public static ObjectType getInstance(final String className) {
037        return new ObjectType(className);
038    }
039
040    private final String className; // Class name of type
041
042    /**
043     * Constructs a new instance.
044     *
045     * @param className fully qualified class name, e.g. {@link String}
046     */
047    public ObjectType(final String className) {
048        super(Const.T_REFERENCE, "L" + Utility.packageToPath(className) + ";");
049        this.className = Utility.pathToPackage(className);
050    }
051
052    /**
053     * Java Virtual Machine Specification edition 2, � 5.4.4 Access Control
054     *
055     * @throws ClassNotFoundException if the class referenced by this type can't be found
056     */
057    public boolean accessibleTo(final ObjectType accessor) throws ClassNotFoundException {
058        final JavaClass jc = Repository.lookupClass(className);
059        if (jc.isPublic()) {
060            return true;
061        }
062        final JavaClass acc = Repository.lookupClass(accessor.className);
063        return acc.getPackageName().equals(jc.getPackageName());
064    }
065
066    /**
067     * @return true if both type objects refer to the same class.
068     */
069    @Override
070    public boolean equals(final Object type) {
071        return type instanceof ObjectType && ((ObjectType) type).className.equals(className);
072    }
073
074    /**
075     * @return name of referenced class
076     */
077    @Override
078    public String getClassName() {
079        return className;
080    }
081
082    /**
083     * @return a hash code value for the object.
084     */
085    @Override
086    public int hashCode() {
087        return className.hashCode();
088    }
089
090    /**
091     * If "this" doesn't reference a class, it references an interface or a non-existant entity.
092     * @deprecated (since 6.0) this method returns an inaccurate result if the class or interface referenced cannot be
093     *             found: use referencesClassExact() instead
094     */
095    @Deprecated
096    public boolean referencesClass() {
097        try {
098            final JavaClass jc = Repository.lookupClass(className);
099            return jc.isClass();
100        } catch (final ClassNotFoundException e) {
101            return false;
102        }
103    }
104
105    /**
106     * Return true if this type references a class, false if it references an interface.
107     *
108     * @return true if the type references a class, false if it references an interface
109     * @throws ClassNotFoundException if the class or interface referenced by this type can't be found
110     */
111    public boolean referencesClassExact() throws ClassNotFoundException {
112        final JavaClass jc = Repository.lookupClass(className);
113        return jc.isClass();
114    }
115
116    /**
117     * If "this" doesn't reference an interface, it references a class or a non-existant entity.
118     *
119     * @deprecated (since 6.0) this method returns an inaccurate result if the class or interface referenced cannot be
120     *             found: use referencesInterfaceExact() instead
121     */
122    @Deprecated
123    public boolean referencesInterface() {
124        try {
125            final JavaClass jc = Repository.lookupClass(className);
126            return !jc.isClass();
127        } catch (final ClassNotFoundException e) {
128            return false;
129        }
130    }
131
132    /**
133     * Return true if this type references an interface, false if it references a class.
134     *
135     * @return true if the type references an interface, false if it references a class
136     * @throws ClassNotFoundException if the class or interface referenced by this type can't be found
137     */
138    public boolean referencesInterfaceExact() throws ClassNotFoundException {
139        final JavaClass jc = Repository.lookupClass(className);
140        return !jc.isClass();
141    }
142
143    /**
144     * Return true if this type is a subclass of given ObjectType.
145     *
146     * @throws ClassNotFoundException if any of this class's superclasses can't be found
147     */
148    public boolean subclassOf(final ObjectType superclass) throws ClassNotFoundException {
149        if (this.referencesInterfaceExact() || superclass.referencesInterfaceExact()) {
150            return false;
151        }
152        return Repository.instanceOf(this.className, superclass.className);
153    }
154}