/*******************************************************************************
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package com.ibm.wala.classLoader;
/**
* Simple object that represents a program counter value (i.e., an instruction in the bytecode)
*/
public class ProgramCounter {
/**
* A constant indicating no source line number information is available.
*/
public static final int NO_SOURCE_LINE_NUMBER = -1;
/**
* Index into bytecode describing this instruction
*/
private final int programCounter;
/**
* @param programCounter Index into bytecode describing this instruction
*/
public ProgramCounter(final int programCounter) {
if (programCounter < 0) {
throw new IllegalArgumentException("illegal programCounter: " + programCounter);
}
this.programCounter = programCounter;
}
/**
* Return the program counter (index into the method's bytecode) for this call site.
*
* @return the program counter (index into the method's bytecode) for this call site.
*
*/
public int getProgramCounter() {
return programCounter;
}
/**
* A Program Counter value is enough to uniquely identify a call site reference within a method.
*
* Note: must use these objects with extreme care; this only works if you never mix ProgramLocations from different methods in the
* same collection.
*
* @see java.lang.Object#equals(Object)
*/
@Override
public boolean equals(Object obj) {
return (obj instanceof ProgramCounter) && ((ProgramCounter) obj).programCounter == programCounter;
}
@Override
public int hashCode() {
return programCounter + 77;
}
@Override
public String toString() {
return "PC@" + programCounter;
}
}