/*
 *    ConstantValueAttribute.java    1.4    03/01/14
 *
 * Copyright © 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

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 );
    }

}