/*
*
*
* Copyright 1990-2007 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.DataInput;
import java.io.IOException;
import util.DataFormatException;
import jcc.Const;
/*
* An abstract class for representing objects in the constant pools
* All constants are derived from here.
* Note how this and all its derivatives are Cloneable.
*/
public
abstract class ConstantObject extends ClassComponent implements Cloneable
{
public int references = 0;
public int ldcReferences = 0;
public boolean shared = false;
public ConstantPool containingPool; // if shared == true, then container.
public int index;
// The type of constant pool entry.
public int tag;
// The number of slots this thing "uses" -- usually 1, sometimes 2
public int nSlots;
public void incldcReference() {
ldcReferences++;
}
public void decldcReference() {
ldcReferences--;
}
public void clearldcReference(){
ldcReferences = 0;
}
// Some items are reference counted so that the most frequently
// accessed ones can be placed in the first 256 entries of the
// constant table. Others are just marked as used so we know
// to include them somewhere in the table.
public void incReference() {
references++;
}
public void decReference() {
references--;
}
public void clearReference(){
references = 0;
}
public Object clone(){
ConstantObject newC;
try {
newC = (ConstantObject)super.clone();
newC.references = 0;
newC.shared = false;
newC.index = 0;
return newC;
} catch( CloneNotSupportedException e ){
e.printStackTrace();
System.exit(1);
}
return null;
}
public abstract boolean isResolved();
static public ConstantObject readObject( DataInput i ) throws IOException{
// read the tag and dispatch accordingly
int tag = i.readUnsignedByte();
switch( tag ){
case Const.CONSTANT_UTF8:
return UnicodeConstant.read( tag, i );
case Const.CONSTANT_INTEGER:
case Const.CONSTANT_FLOAT:
return SingleValueConstant.read( tag, i );
case Const.CONSTANT_DOUBLE:
case Const.CONSTANT_LONG:
return DoubleValueConstant.read( tag, i );
case Const.CONSTANT_STRING:
return StringConstant.read( tag, i );
case Const.CONSTANT_NAMEANDTYPE:
return NameAndTypeConstant.read( tag, i );
case Const.CONSTANT_CLASS:
return ClassConstant.read( tag, i );
case Const.CONSTANT_FIELD:
return FieldConstant.read( tag, i );
case Const.CONSTANT_METHOD:
return MethodConstant.read( tag, i );
case Const.CONSTANT_INTERFACEMETHOD:
return InterfaceConstant.read( tag, i );
default:
throw new DataFormatException("Format error (constant tag "+tag+" )");
}
}
}
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