Source code

    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>
    029 * attribute and is used only there. It contains a range in which a
    030 * particular exception handler is active.
    031 *
    032 * @see     Code
    033 */
    034public final class CodeException implements Cloneable, Node, Constants {
    035
    036    private int start_pc; // Range in the code the exception handler is
    037    private int end_pc; // active. start_pc is inclusive, end_pc exclusive
    038    private int handler_pc; /* Starting address of exception handler, i.e.,
    039     * an offset from start of code.
    040     */
    041    private int catch_type; /* If this is zero the handler catches any
    042     * exception, otherwise it points to the
    043     * exception class which is to be caught.
    044     */
    045
    046
    047    /**
    048     * Initialize from another object.
    049     */
    050    public CodeException(final CodeException c) {
    051        this(c.getStartPC(), c.getEndPC(), c.getHandlerPC(), c.getCatchType());
    052    }
    053
    054
    055    /**
    056     * Construct object from file stream.
    057     * @param file Input stream
    058     * @throws IOException
    059     */
    060    CodeException(final DataInput file) throws IOException {
    061        this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file
    062                .readUnsignedShort());
    063    }
    064
    065
    066    /**
    067     * @param start_pc Range in the code the exception handler is active,
    068     * start_pc is inclusive while
    069     * @param end_pc is exclusive
    070     * @param handler_pc Starting address of exception handler, i.e.,
    071     * an offset from start of code.
    072     * @param catch_type If zero the handler catches any
    073     * exception, otherwise it points to the exception class which is
    074     * to be caught.
    075     */
    076    public CodeException(final int start_pc, final int end_pc, final int handler_pc, final int catch_type) {
    077        this.start_pc = start_pc;
    078        this.end_pc = end_pc;
    079        this.handler_pc = handler_pc;
    080        this.catch_type = catch_type;
    081    }
    082
    083
    084    /**
    085     * Called by objects that are traversing the nodes of the tree implicitely
    086     * defined by the contents of a Java class. I.e., the hierarchy of methods,
    087     * fields, attributes, etc. spawns a tree of objects.
    088     *
    089     * @param v Visitor object
    090     */
    091    @Override
    092    public void accept( final Visitor v ) {
    093        v.visitCodeException(this);
    094    }
    095
    096
    097    /**
    098     * Dump code exception to file stream in binary format.
    099     *
    100     * @param file Output file stream
    101     * @throws IOException
    102     */
    103    public void dump( final DataOutputStream file ) throws IOException {
    104        file.writeShort(start_pc);
    105        file.writeShort(end_pc);
    106        file.writeShort(handler_pc);
    107        file.writeShort(catch_type);
    108    }
    109
    110
    111    /**
    112     * @return 0, if the handler catches any exception, otherwise it points to
    113     * the exception class which is to be caught.
    114     */
    115    public int getCatchType() {
    116        return catch_type;
    117    }
    118
    119
    120    /**
    121     * @return Exclusive end index of the region where the handler is active.
    122     */
    123    public int getEndPC() {
    124        return end_pc;
    125    }
    126
    127
    128    /**
    129     * @return Starting address of exception handler, relative to the code.
    130     */
    131    public int getHandlerPC() {
    132        return handler_pc;
    133    }
    134
    135
    136    /**
    137     * @return Inclusive start index of the region where the handler is active.
    138     */
    139    public int getStartPC() {
    140        return start_pc;
    141    }
    142
    143
    144    /**
    145     * @param catch_type the type of exception that is caught
    146     */
    147    public void setCatchType( final int catch_type ) {
    148        this.catch_type = catch_type;
    149    }
    150
    151
    152    /**
    153     * @param end_pc end of handled block
    154     */
    155    public void setEndPC( final int end_pc ) {
    156        this.end_pc = end_pc;
    157    }
    158
    159
    160    /**
    161     * @param handler_pc where the actual code is
    162     */
    163    public void setHandlerPC( final int handler_pc ) { // TODO unused
    164        this.handler_pc = handler_pc;
    165    }
    166
    167
    168    /**
    169     * @param start_pc start of handled block
    170     */
    171    public void setStartPC( final int start_pc ) { // TODO unused
    172        this.start_pc = start_pc;
    173    }
    174
    175
    176    /**
    177     * @return String representation.
    178     */
    179    @Override
    180    public String toString() {
    181        return "CodeException(start_pc = " + start_pc + ", end_pc = " + end_pc + ", handler_pc = "
    182                + handler_pc + ", catch_type = " + catch_type + ")";
    183    }
    184
    185
    186    /**
    187     * @return String representation.
    188     */
    189    public String toString( final ConstantPool cp, final boolean verbose ) {
    190        String str;
    191        if (catch_type == 0) {
    192            str = "<Any exception>(0)";
    193        } else {
    194            str = Utility.compactClassName(cp.getConstantString(catch_type, Const.CONSTANT_Class), false)
    195                    + (verbose ? "(" + catch_type + ")" : "");
    196        }
    197        return start_pc + "\t" + end_pc + "\t" + handler_pc + "\t" + str;
    198    }
    199
    200
    201    public String toString( final ConstantPool cp ) {
    202        return toString(cp, true);
    203    }
    204
    205
    206    /**
    207     * @return deep copy of this object
    208     */
    209    public CodeException copy() {
    210        try {
    211            return (CodeException) clone();
    212        } catch (final CloneNotSupportedException e) {
    213            // TODO should this throw?
    214        }
    215        return null;
    216    }
    217}