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 *
017 */
018package org.apache.bcel.classfile;
019
020import java.io.DataInput;
021import java.io.DataOutputStream;
022import java.io.IOException;
023
024import org.apache.bcel.Const;
025import org.apache.bcel.Constants;
026
027/**
028 * This class represents an entry in the exception table of the <em>Code</em> attribute and is used only there. It
029 * contains a range in which a particular exception handler is active.
030 *
031 * @see Code
032 */
033public final class CodeException implements Cloneable, Node, Constants {
034
035    /**
036     * Empty array.
037     */
038    static final CodeException[] EMPTY_CODE_EXCEPTION_ARRAY = {};
039    private int startPc; // Range in the code the exception handler is
040    private int endPc; // active. startPc is inclusive, endPc exclusive
041    private int handlerPc; /*
042                            * Starting address of exception handler, i.e., an offset from start of code.
043                            */
044
045    private int catchType; /*
046                            * If this is zero the handler catches any exception, otherwise it points to the exception class which is to be caught.
047                            */
048
049    /**
050     * Initialize from another object.
051     */
052    public CodeException(final CodeException c) {
053        this(c.getStartPC(), c.getEndPC(), c.getHandlerPC(), c.getCatchType());
054    }
055
056    /**
057     * Construct object from file stream.
058     *
059     * @param file Input stream
060     * @throws IOException if an I/O error occurs.
061     */
062    CodeException(final DataInput file) throws IOException {
063        this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort());
064    }
065
066    /**
067     * @param startPc Range in the code the exception handler is active, startPc is inclusive while
068     * @param endPc is exclusive
069     * @param handlerPc Starting address of exception handler, i.e., an offset from start of code.
070     * @param catchType If zero the handler catches any exception, otherwise it points to the exception class which is to be
071     *        caught.
072     */
073    public CodeException(final int startPc, final int endPc, final int handlerPc, final int catchType) {
074        this.startPc = startPc;
075        this.endPc = endPc;
076        this.handlerPc = handlerPc;
077        this.catchType = catchType;
078    }
079
080    /**
081     * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class.
082     * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
083     *
084     * @param v Visitor object
085     */
086    @Override
087    public void accept(final Visitor v) {
088        v.visitCodeException(this);
089    }
090
091    /**
092     * @return deep copy of this object
093     */
094    public CodeException copy() {
095        try {
096            return (CodeException) clone();
097        } catch (final CloneNotSupportedException e) {
098            // TODO should this throw?
099        }
100        return null;
101    }
102
103    /**
104     * Dump code exception to file stream in binary format.
105     *
106     * @param file Output file stream
107     * @throws IOException if an I/O error occurs.
108     */
109    public void dump(final DataOutputStream file) throws IOException {
110        file.writeShort(startPc);
111        file.writeShort(endPc);
112        file.writeShort(handlerPc);
113        file.writeShort(catchType);
114    }
115
116    /**
117     * @return 0, if the handler catches any exception, otherwise it points to the exception class which is to be caught.
118     */
119    public int getCatchType() {
120        return catchType;
121    }
122
123    /**
124     * @return Exclusive end index of the region where the handler is active.
125     */
126    public int getEndPC() {
127        return endPc;
128    }
129
130    /**
131     * @return Starting address of exception handler, relative to the code.
132     */
133    public int getHandlerPC() {
134        return handlerPc;
135    }
136
137    /**
138     * @return Inclusive start index of the region where the handler is active.
139     */
140    public int getStartPC() {
141        return startPc;
142    }
143
144    /**
145     * @param catchType the type of exception that is caught
146     */
147    public void setCatchType(final int catchType) {
148        this.catchType = catchType;
149    }
150
151    /**
152     * @param endPc end of handled block
153     */
154    public void setEndPC(final int endPc) {
155        this.endPc = endPc;
156    }
157
158    /**
159     * @param handlerPc where the actual code is
160     */
161    public void setHandlerPC(final int handlerPc) { // TODO unused
162        this.handlerPc = handlerPc;
163    }
164
165    /**
166     * @param startPc start of handled block
167     */
168    public void setStartPC(final int startPc) { // TODO unused
169        this.startPc = startPc;
170    }
171
172    /**
173     * @return String representation.
174     */
175    @Override
176    public String toString() {
177        return "CodeException(startPc = " + startPc + ", endPc = " + endPc + ", handlerPc = " + handlerPc + ", catchType = " + catchType + ")";
178    }
179
180    public String toString(final ConstantPool cp) {
181        return toString(cp, true);
182    }
183
184    /**
185     * @return String representation.
186     */
187    public String toString(final ConstantPool cp, final boolean verbose) {
188        String str;
189        if (catchType == 0) {
190            str = "<Any exception>(0)";
191        } else {
192            str = Utility.compactClassName(cp.getConstantString(catchType, Const.CONSTANT_Class), false) + (verbose ? "(" + catchType + ")" : "");
193        }
194        return startPc + "\t" + endPc + "\t" + handlerPc + "\t" + str;
195    }
196}