/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *   Free SoftwareFoundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.xpath.functions;

import com.caucho.util.L10N;
import com.caucho.xml.XmlPrinter;
import com.caucho.xpath.Expr;
import com.caucho.xpath.ExprEnvironment;
import com.caucho.xpath.XPathException;
import com.caucho.xpath.XPathParseException;
import com.caucho.xpath.expr.AbstractStringExpr;
import com.caucho.xpath.pattern.NodeIterator;

import org.w3c.dom.Node;

import java.io.IOException;

/**
 * Traces an object.
 */
public class Trace extends AbstractStringExpr {
  private static final L10N L = new L10N(ResolveURI.class);
  
  private Expr _expr;
  private Expr _labelExpr;

  public Trace(Expr expr, Expr labelExpr)
    throws XPathParseException
  {
    _expr = expr;
    _labelExpr = labelExpr;

    if (expr == null)
      throw new XPathParseException(L.l("fn:trace(value,[label])"));
  }

  /**
   * Evaluates the expression as an string.
   *
   * @param node the current node
   * @param env the variable environment.
   *
   * @return the string representation of the expression.
   */
  public String evalString(Node node, ExprEnvironment env)
    throws XPathException
  {
    Object value = _expr.evalObject(node, env);

    if (value instanceof NodeIterator) {
      NodeIterator iter = (NodeIterator) value;

      while (iter.hasNext()) {
	Node subnode = iter.next();

	XmlPrinter printer = new XmlPrinter(System.out);

	try {
	  printer.printPrettyXml(subnode);
	} catch (IOException e) {
	}
      }
    }
    else if (value instanceof Node) {
	Node subnode = (Node) value;

	XmlPrinter printer = new XmlPrinter(System.out);

	try {
	  printer.printPrettyXml(subnode);
	} catch (IOException e) {
	}
    }
    else
      System.out.println(value);

    return "";
  }

  public String toString()
  {
    return "fn:trace(" + _expr + ")";
  }
}
