ConstantValueAttribute.java

/*
 *   
 *
 * Copyright  1990-2009 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.DataFormatException;

/*
 * A class to represent the ConstantValue Attribute
 * of a field
 */

public
class ConstantValueAttribute extends Attribute
{
    public ConstantObject	data;

    public
    ConstantValueAttribute( UnicodeConstant name, int l, ConstantObject d ){
	super( name, l );
	data = d;
    }

    public void
    externalize( ConstantPool p ){
	super.externalize( p );
	data = p.dup( data );
    }

    protected int
    writeData( DataOutput o ) throws IOException{
	o.writeShort( data.index );
	return 2;
    }

    public void
    countConstantReferences( boolean isRelocatable ){
	super.countConstantReferences( isRelocatable );
	data.incReference();
    }

    public static Attribute
    readAttribute( DataInput i, ConstantObject globals[] ) throws IOException{
	UnicodeConstant name;

	name = (UnicodeConstant)globals[i.readUnsignedShort()];
	return finishReadAttribute( i, name, globals );
    }

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

	l  = i.readInt();
	n  = i.readUnsignedShort();
	d  = globals[n];
	return new ConstantValueAttribute( name, l, d );
    }

}