    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 * @version $Id$
    033 * @see     Code
    034 */
    035public final class CodeException implements Cloneable, Node, Constants {
    036
    037    private int start_pc; // Range in the code the exception handler is
    038    private int end_pc; // active. start_pc is inclusive, end_pc exclusive
    039    private int handler_pc; /* Starting address of exception handler, i.e.,
    040     * an offset from start of code.
    041     */
    042    private int catch_type; /* If this is zero the handler catches any
    043     * exception, otherwise it points to the
    044     * exception class which is to be caught.
    045     */
    046
    047
    048    /**
    049     * Initialize from another object.
    050     */
    051    public CodeException(final CodeException c) {
    052        this(c.getStartPC(), c.getEndPC(), c.getHandlerPC(), c.getCatchType());
    053    }
    054
    055
    056    /**
    057     * Construct object from file stream.
    058     * @param file Input stream
    059     * @throws IOException
    060     */
    061    CodeException(final DataInput file) throws IOException {
    062        this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file
    063                .readUnsignedShort());
    064    }
    065
    066
    067    /**
    068     * @param start_pc Range in the code the exception handler is active,
    069     * start_pc is inclusive while
    070     * @param end_pc is exclusive
    071     * @param handler_pc Starting address of exception handler, i.e.,
    072     * an offset from start of code.
    073     * @param catch_type If zero the handler catches any
    074     * exception, otherwise it points to the exception class which is
    075     * to be caught.
    076     */
    077    public CodeException(final int start_pc, final int end_pc, final int handler_pc, final int catch_type) {
    078        this.start_pc = start_pc;
    079        this.end_pc = end_pc;
    080        this.handler_pc = handler_pc;
    081        this.catch_type = catch_type;
    082    }
    083
    084
    085    /**
    086     * Called by objects that are traversing the nodes of the tree implicitely
    087     * defined by the contents of a Java class. I.e., the hierarchy of methods,
    088     * fields, attributes, etc. spawns a tree of objects.
    089     *
    090     * @param v Visitor object
    091     */
    092    @Override
    093    public void accept( final Visitor v ) {
    094        v.visitCodeException(this);
    095    }
    096
    097
    098    /**
    099     * Dump code exception to file stream in binary format.
    100     *
    101     * @param file Output file stream
    102     * @throws IOException
    103     */
    104    public final void dump( final DataOutputStream file ) throws IOException {
    105        file.writeShort(start_pc);
    106        file.writeShort(end_pc);
    107        file.writeShort(handler_pc);
    108        file.writeShort(catch_type);
    109    }
    110
    111
    112    /**
    113     * @return 0, if the handler catches any exception, otherwise it points to
    114     * the exception class which is to be caught.
    115     */
    116    public final int getCatchType() {
    117        return catch_type;
    118    }
    119
    120
    121    /**
    122     * @return Exclusive end index of the region where the handler is active.
    123     */
    124    public final int getEndPC() {
    125        return end_pc;
    126    }
    127
    128
    129    /**
    130     * @return Starting address of exception handler, relative to the code.
    131     */
    132    public final int getHandlerPC() {
    133        return handler_pc;
    134    }
    135
    136
    137    /**
    138     * @return Inclusive start index of the region where the handler is active.
    139     */
    140    public final int getStartPC() {
    141        return start_pc;
    142    }
    143
    144
    145    /**
    146     * @param catch_type the type of exception that is caught
    147     */
    148    public final void setCatchType( final int catch_type ) {
    149        this.catch_type = catch_type;
    150    }
    151
    152
    153    /**
    154     * @param end_pc end of handled block
    155     */
    156    public final void setEndPC( final int end_pc ) {
    157        this.end_pc = end_pc;
    158    }
    159
    160
    161    /**
    162     * @param handler_pc where the actual code is
    163     */
    164    public final void setHandlerPC( final int handler_pc ) { // TODO unused
    165        this.handler_pc = handler_pc;
    166    }
    167
    168
    169    /**
    170     * @param start_pc start of handled block
    171     */
    172    public final void setStartPC( final int start_pc ) { // TODO unused
    173        this.start_pc = start_pc;
    174    }
    175
    176
    177    /**
    178     * @return String representation.
    179     */
    180    @Override
    181    public final String toString() {
    182        return "CodeException(start_pc = " + start_pc + ", end_pc = " + end_pc + ", handler_pc = "
    183                + handler_pc + ", catch_type = " + catch_type + ")";
    184    }
    185
    186
    187    /**
    188     * @return String representation.
    189     */
    190    public final String toString( final ConstantPool cp, final boolean verbose ) {
    191        String str;
    192        if (catch_type == 0) {
    193            str = "<Any exception>(0)";
    194        } else {
    195            str = Utility.compactClassName(cp.getConstantString(catch_type, Const.CONSTANT_Class), false)
    196                    + (verbose ? "(" + catch_type + ")" : "");
    197        }
    198        return start_pc + "\t" + end_pc + "\t" + handler_pc + "\t" + str;
    199    }
    200
    201
    202    public final String toString( final ConstantPool cp ) {
    203        return toString(cp, true);
    204    }
    205
    206
    207    /**
    208     * @return deep copy of this object
    209     */
    210    public CodeException copy() {
    211        try {
    212            return (CodeException) clone();
    213        } catch (final CloneNotSupportedException e) {
    214            // TODO should this throw?
    215        }
    216        return null;
    217    }
    218}