org.eclipse.jdt.debug/jdi/org/eclipse/jdi/internal/LocalVariableImpl.java

package org.eclipse.jdi.internal;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */

import com.sun.jdi.*;
import com.sun.jdi.connect.*;
import com.sun.jdi.event.*;
import com.sun.jdi.request.*;
import org.eclipse.jdi.internal.connect.*;
import org.eclipse.jdi.internal.request.*;
import org.eclipse.jdi.internal.event.*;
import org.eclipse.jdi.internal.jdwp.*;
import org.eclipse.jdi.internal.spy.*;
import java.util.*;
import java.io.*;

/**
 * this class implements the corresponding interfaces
 * declared by the JDI specification. See the com.sun.jdi package
 * for more information.
 *
 */
public class LocalVariableImpl extends MirrorImpl implements LocalVariable {
	/** Method that holds local variable. */
	private MethodImpl fMethod;
	/** First code index at which the variable is visible (unsigned). */
	private long fCodeIndex;
	/** The variable's name. */
	private String fName;
	/** The variable type's JNI signature. */
	private String fSignature;
	/** Unsigned value used in conjunction with codeIndex. The variable can be get or set only when the current codeIndex <= current frame code index < code index + length. */
	private int fLength;
	/** The local variable's index in its frame. */
	private int fSlot;
	/** Is the local variable an argument of its method? */
	private boolean fIsArgument;
	
	public LocalVariableImpl(VirtualMachineImpl vmImpl, MethodImpl method, long codeIndex, String name, String signature, int length, int slot, boolean isArgument) {
		super("LocalVariable", vmImpl);
		fMethod = method;
		fCodeIndex = codeIndex;
		fName = name;
		fSignature = signature;
		fLength = length;
		fSlot = slot;
		fIsArgument = isArgument;
	}

	/** 
	 * @return Returns local variable's index in its frame.
	 */
	public int slot() {
		return fSlot;
	}
	
	/** 
	 * @return Returns the hash code value.
	 */
	public int hashCode() {
		return fMethod.hashCode() + (int)fCodeIndex + fSlot;
	}
	
	/**
	 * @return Returns true if two mirrors refer to the same entity in the target VM.
	 * @see java.lang.Object#equals(Object).
	 */
	public boolean equals(Object object) {
		if (object != null && object.getClass().equals(this.getClass())) {
			LocalVariableImpl loc = (LocalVariableImpl)object;
			return fMethod.equals(loc.fMethod) && fCodeIndex == loc.fCodeIndex && fSlot == loc.fSlot;
		}
		return false;
	}
	
	/**
	 * @return Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
	 */
	public int compareTo(Object object) {
		if (object == null || !object.getClass().equals(this.getClass()))
			throw new ClassCastException("Can't compare local variable to given object.");
		
		// See if methods are the same, if not return comparison between methods.
		LocalVariableImpl var2 = (LocalVariableImpl)object;
		if (!method().equals(var2.method()))
			return method().compareTo(var2.method());

		// Return comparison between the index of each local variable in its stack frame.
		// Code indexes must be treated as unsigned. This matters if you have to compare them.
		if (fCodeIndex < 0 || var2.fCodeIndex < 0)
			throw new InternalError("Code indexes are assumed to be always positive.");
		
		long index2 = var2.fCodeIndex;
		if (fCodeIndex < index2)
			return -1;
		else if (fCodeIndex > index2)
			return 1;
		else return 0;
	}
	
	/** 
	 * @return Returns true if this variable is an argument to its method.
	 */
	public boolean isArgument() {
		return fIsArgument;
	}
	
	public boolean isVisible(StackFrame frame) throws IllegalArgumentException, VMMismatchException {
		checkVM(frame);
		StackFrameImpl frameImpl = (StackFrameImpl)frame;
		if (!fMethod.equals(frameImpl.location().method()))
			throw new IllegalArgumentException("The stack frame's method does not match this variable's method.");

		long currentIndex = frameImpl.location().codeIndex();
		
		// Code indexes must be treated as unsigned. This matters if you have to compare them.
		if (currentIndex >= 0 && fCodeIndex >= 0 && fCodeIndex + fLength >= 0)
			return fCodeIndex <= currentIndex && currentIndex < fCodeIndex + fLength;

		throw new InternalError("Code indexes are assumed to be always positive.");
	}
	
	/** 
	 * @return Returns the name of the local variable.
	 */
	public String name() {
		return fName;
	}
	
	/** 
	 * @return Returns the signature of the local variable.
	 */
	public String signature() {
		return fSignature;
	}
	
	/** 
	 * @return Returns the type of the this LocalVariable. 
	 */
	public Type type() throws ClassNotLoadedException {
		return TypeImpl.create(virtualMachineImpl(), fSignature, method().declaringType().classLoader());
	}
	
	/** 
	 * @return Returns a text representation of the declared type of this variable.
	 */
	public String typeName() { 
		return TypeImpl.signatureToName(fSignature);
	}
	
	/** 
	 * @return Returns the tag of the declared type of this variable.
	 */
	public byte tag() { 
		return TypeImpl.signatureToTag(fSignature);
	}
	
	/** 
	 * @return Returns the method that holds the local variable.
	 */
	public MethodImpl method() { 
		return fMethod;
	}
	
	/** 
	 * @return Returns true if the local variable is the 'this' pointer.
	 */
	public boolean isThis() {
		return slot() == 0 && !method().isStatic();
	}
	
	/**
	 * @return Returns description of Mirror object.
	 */
	public String toString() {
		return fName;
	}

}