/******************************************************************************
 * Copyright (c) 2011 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.cast.js.ipa.callgraph.correlations.extraction;

import com.ibm.wala.cast.tree.CAstNode;

/**
 * A {@link NodePos} for a non-root node; includes information about the parent node, the child index, and
 * the position of the parent node.
 * 
 * @author mschaefer
 *
 */
public class ChildPos extends NodePos {
	private CAstNode parent;
	private int index;
	private NodePos parent_pos;
	
	public ChildPos(CAstNode parent, int index, NodePos parent_pos) {
		this.parent = parent;
		this.index = index;
		this.parent_pos = parent_pos;
	}
	
	public CAstNode getParent() {
		return parent;
	}
	
	public int getIndex() {
		return index;
	}
	
	public NodePos getParentPos() {
		return parent_pos;
	}
	
	public CAstNode getChild() {
	  return parent.getChild(index);
	}
	
	public ChildPos getChildPos(int index) {
	  return new ChildPos(this.getChild(), index, this);
	}
	
	@Override
	public <A> A accept(PosSwitch<A> ps) {
		return ps.caseChildPos(this);
	}

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + index;
    result = prime * result + ((parent == null) ? 0 : parent.hashCode());
    result = prime * result + ((parent_pos == null) ? 0 : parent_pos.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    ChildPos other = (ChildPos) obj;
    if (index != other.index)
      return false;
    if (parent == null) {
      if (other.parent != null)
        return false;
    } else if (!parent.equals(other.parent))
      return false;
    if (parent_pos == null) {
      if (other.parent_pos != null)
        return false;
    } else if (!parent_pos.equals(other.parent_pos))
      return false;
    return true;
  }
}