MethodVisitor.java

package gr.gousiosg.callgraph;

import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.ConstantPushInstruction;
import org.apache.bcel.generic.EmptyVisitor;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionConstants;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InvokeInstruction;
import org.apache.bcel.generic.MethodGen;
import org.apache.bcel.generic.ReturnInstruction;

/**
 * The simplest of method visitors, prints any invoked method
 * signature for all method invocations.
 * 
 * Class copied with modifications from CJKM: http://www.spinellis.gr/sw/ckjm/
 */
public class MethodVisitor extends EmptyVisitor {

    JavaClass visitedClass;
    private MethodGen mg;
    private ConstantPoolGen cp;
    private String format;

    public MethodVisitor(MethodGen m, JavaClass jc) {
        visitedClass = jc;
        mg = m;
        cp = mg.getConstantPool();
        format = visitedClass.getClassName() + ":" + mg.getName() + "->" + "%s:%s";
    }

    public void start() {
        if (mg.isAbstract() || mg.isNative())
            return;
        for (InstructionHandle ih = mg.getInstructionList().getStart(); 
                ih != null; ih = ih.getNext()) {
            Instruction i = ih.getInstruction();
            
            if (!visitInstruction(i))
                i.accept(this);
        }
    }

    private boolean visitInstruction(Instruction i) {
        short opcode = i.getOpcode();

        return ((InstructionConstants.INSTRUCTIONS[opcode] != null)
                && !(i instanceof ConstantPushInstruction) 
                && !(i instanceof ReturnInstruction));
    }

    /** Method invocation. */
    public void visitInvokeInstruction(InvokeInstruction i) {
        System.out.println(String.format(format,i.getReferenceType(cp),i.getMethodName(cp))); 
    }
}