exceptionsattribute.java

来自「This is a resource based on j2me embedde」· Java 代码 · 共 113 行

/*
 * @(#)ExceptionsAttribute.java	1.14 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.  
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER  
 *   
 * This program is free software; you can redistribute it and/or  
 * modify it under the terms of the GNU General Public License version  
 * 2 only, as published by the Free Software Foundation.   
 *   
 * This program is distributed in the hope that it will be useful, but  
 * WITHOUT ANY WARRANTY; without even the implied warranty of  
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU  
 * General Public License version 2 for more details (a copy is  
 * included at /legal/license.txt).   
 *   
 * You should have received a copy of the GNU General Public License  
 * version 2 along with this work; if not, write to the Free Software  
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  
 * 02110-1301 USA   
 *   
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa  
 * Clara, CA 95054 or visit www.sun.com if you need additional  
 * information or have any questions. 
 *
 */

package components;
import java.io.DataOutput;
import java.io.DataInput;
import java.io.IOException;
import util.*;

/*
 * A class to represent the Exceptions table Attribute
 * of a method
 */

public
class ExceptionsAttribute extends Attribute
{
    public ClassConstant	data[];

    public
    ExceptionsAttribute( UnicodeConstant name, int l, ClassConstant d[] ){
	super( name, l );
	data = d;
    }

    public void 
    countConstantReferences( boolean isRelocatable ){
	super.countConstantReferences( isRelocatable );
	int n = data.length;
	for ( int i = 0; i < n; i++ ){
	    data[i].incReference();
	}
    }

    /*
     * This method can only be called at the very end of processing,
     * just before output writing.  We call super.validate to make
     * sure that the UnicodeConstant that is the attribute name
     * is not in the constant pool.
     * Then we validate all the ClassConstants in the attribute, to make
     * sure that they're all in a constant pool.
     */
    public void
    validate(){
	super.validate();
	int n = data.length;
	for ( int i = 0; i < n; i++ ){
	    data[i].validate();
	}
    }

    protected int
    writeData( DataOutput o ) throws IOException{
	int n = data.length;
	o.writeShort( n );
	for ( int i = 0; i < n; i++ ){
	    o.writeShort( data[i].index );
	    // debug
	    if ( data[i].index <= 0 ){
		System.err.println(Localizer.getString("exceptionsattribute.exceptions_table_references_negative_subscript", data[i]));
	    }
	    // end debug
	}
	return 2 + 2*n;
    }

    //
    // for those cases where we already read the name index
    // and know that its not something requiring special handling.
    //
    public static Attribute
    finishReadAttribute( DataInput in, UnicodeConstant name, ConstantPool cp ) throws IOException {
	int l;
	int n;
	ClassConstant d[];

	l  = in.readInt();
	n  = in.readUnsignedShort();
	d = new ClassConstant[ n ];
	ConstantObject[] t = cp.getConstants();
	for ( int i = 0; i < n; i++ ){
	    int index = in.readUnsignedShort();
	    d[i] = (ClassConstant)t[ index ];
	}
	return new ExceptionsAttribute( name, l, d );
    }

}