org.aspectj/bcel-builder/src/main/java/org/aspectj/apache/bcel/classfile/ExceptionTable.java

package org.aspectj.apache.bcel.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
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 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
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 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
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 *
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import org.aspectj.apache.bcel.Constants;

/**
 * This class represents the table of exceptions that are thrown by a method. This attribute may be used once per method. The name
 * of this class is <em>ExceptionTable</em> for historical reasons; The Java Virtual Machine Specification, Second Edition defines
 * this attribute using the name <em>Exceptions</em> (which is inconsistent with the other classes).
 *
 * @version $Id: ExceptionTable.java,v 1.5 2009/09/15 19:40:12 aclement Exp $
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @see Code
 */
public final class ExceptionTable extends Attribute {
	private int number_of_exceptions; // Table of indices into
	private int[] exception_index_table; // constant pool

	/**
	 * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a physical
	 * copy.
	 */
	public ExceptionTable(ExceptionTable c) {
		this(c.getNameIndex(), c.getLength(), c.getExceptionIndexTable(), c.getConstantPool());
	}

	/**
	 * @param name_index Index in constant pool
	 * @param length Content length in bytes
	 * @param exception_index_table Table of indices in constant pool
	 * @param constant_pool Array of constants
	 */
	public ExceptionTable(int name_index, int length, int[] exception_index_table, ConstantPool constant_pool) {
		super(Constants.ATTR_EXCEPTIONS, name_index, length, constant_pool);
		setExceptionIndexTable(exception_index_table);
	}

	/**
	 * Construct object from file stream.
	 *
	 * @param name_index Index in constant pool
	 * @param length Content length in bytes
	 * @param file Input stream
	 * @param constant_pool Array of constants
	 * @throws IOException
	 */
	ExceptionTable(int name_index, int length, DataInputStream file, ConstantPool constant_pool) throws IOException {
		this(name_index, length, (int[]) null, constant_pool);

		number_of_exceptions = file.readUnsignedShort();
		exception_index_table = new int[number_of_exceptions];

		for (int i = 0; i < number_of_exceptions; i++)
			exception_index_table[i] = file.readUnsignedShort();
	}

	/**
	 * Called by objects that are traversing the nodes of the tree implicitely defined by the contents of a Java class. I.e., the
	 * hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
	 *
	 * @param v Visitor object
	 */
	@Override
	public void accept(ClassVisitor v) {
		v.visitExceptionTable(this);
	}

	/**
	 * Dump exceptions attribute to file stream in binary format.
	 *
	 * @param file Output file stream
	 * @throws IOException
	 */
	@Override
	public final void dump(DataOutputStream file) throws IOException {
		super.dump(file);
		file.writeShort(number_of_exceptions);
		for (int i = 0; i < number_of_exceptions; i++)
			file.writeShort(exception_index_table[i]);
	}

	/**
	 * @return Array of indices into constant pool of thrown exceptions.
	 */
	public final int[] getExceptionIndexTable() {
		return exception_index_table;
	}

	/**
	 * @return Length of exception table.
	 */
	public final int getNumberOfExceptions() {
		return number_of_exceptions;
	}

	/**
	 * @return class names of thrown exceptions
	 */
	public final String[] getExceptionNames() {
		String[] names = new String[number_of_exceptions];
		for (int i = 0; i < number_of_exceptions; i++)
			names[i] = cpool.getConstantString(exception_index_table[i], Constants.CONSTANT_Class).replace('/', '.');
		return names;
	}

	/**
	 * @param exception_index_table. Also redefines number_of_exceptions according to table length.
	 */
	public final void setExceptionIndexTable(int[] exception_index_table) {
		this.exception_index_table = exception_index_table;
		number_of_exceptions = (exception_index_table == null) ? 0 : exception_index_table.length;
	}

	/**
	 * @return String representation, i.e., a list of thrown exceptions.
	 */
	@Override
	public final String toString() {
		StringBuilder buf = new StringBuilder("");
		String str;

		for (int i = 0; i < number_of_exceptions; i++) {
			str = cpool.getConstantString(exception_index_table[i], Constants.CONSTANT_Class);
			buf.append(Utility.compactClassName(str, false));

			if (i < number_of_exceptions - 1)
				buf.append(", ");
		}

		return buf.toString();
	}

	// /**
	// * @return deep copy of this attribute
	// */
	// public Attribute copy(ConstantPool constant_pool) {
	// ExceptionTable c = (ExceptionTable)clone();
	// c.exception_index_table = (int[])exception_index_table.clone();
	// c.cpool = constant_pool;
	// return c;
	// }
}