/*
 * DomXPathResult.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP 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.
 * 
 * GNU JAXP 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.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package gnu.xml.dom;

import java.util.Collection;
import java.util.Iterator;
import org.w3c.dom.DOMException;
import org.w3c.dom.Node;
import org.w3c.dom.xpath.XPathException;
import org.w3c.dom.xpath.XPathNSResolver;
import org.w3c.dom.xpath.XPathResult;

/**
 * An XPath result object.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
class DomXPathResult
implements XPathResult
{

  final Object value;
  final short type;
  Iterator iterator;

  DomXPathResult (Object value, short requestedType)
  {
    this.value = value;
    if (value instanceof Boolean)
      {
        type = XPathResult.BOOLEAN_TYPE;
      }
    else if (value instanceof Double)
      {
        type = XPathResult.NUMBER_TYPE;
      }
    else if (value instanceof String)
      {
        type = XPathResult.STRING_TYPE;
      }
    else if (value instanceof Collection)
      {
        Collection ns = (Collection) value;
        switch (requestedType)
          {
          case XPathResult.ANY_TYPE:
          case XPathResult.ANY_UNORDERED_NODE_TYPE:
            type = (ns.size () == 1) ? XPathResult.FIRST_ORDERED_NODE_TYPE :
              XPathResult.ORDERED_NODE_ITERATOR_TYPE;
            break;
          default:
            type = requestedType;
          }
        iterator = ns.iterator ();
      }
    else
      {
        throw new IllegalArgumentException ();
      }
  }

  public boolean getBooleanValue()
  {
    if (type == XPathResult.BOOLEAN_TYPE)
      {
        return ((Boolean) value).booleanValue ();
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public boolean getInvalidIteratorState()
  {
    return iterator == null;
  }

  public double getNumberValue()
  {
    if (type == XPathResult.NUMBER_TYPE)
      {
        return ((Double) value).doubleValue ();
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public short getResultType()
  {
    return type;
  }

  public Node getSingleNodeValue()
  {
    switch (type)
      {
      case XPathResult.FIRST_ORDERED_NODE_TYPE:
      case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
      case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
        Collection ns = (Collection) value;
        if (ns.isEmpty ())
          {
            return null;
          }
        else
          {
            return (Node) ns.iterator ().next ();
          }
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public int getSnapshotLength()
  {
    switch (type)
      {
      case XPathResult.FIRST_ORDERED_NODE_TYPE:
      case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
      case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
        return ((Collection) value).size ();
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public String getStringValue()
  {
    if (type == XPathResult.STRING_TYPE)
      {
        return (String) value;
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public Node iterateNext()
  {
    if (iterator != null)
      {
        if (iterator.hasNext ())
          {
            return (Node) iterator.next ();
          }
        else
          {
            iterator = null;
            return null;
          }
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public Node snapshotItem(int index)
  {
    switch (type)
      {
      case XPathResult.FIRST_ORDERED_NODE_TYPE:
      case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
      case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
      case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
        Collection ns = (Collection) value;
        Node[] nodes = new Node[ns.size ()];
        ns.toArray (nodes);
        return nodes[index];
      }
    throw new XPathException (XPathException.TYPE_ERR, value.toString ());
  }

  public String toString ()
  {
    return getClass ().getName () + "[type=" + typeName (type) + ",value=" +
      value + ']';
  }

  private String typeName (short type)
  {
    switch (type)
      {
      case XPathResult.BOOLEAN_TYPE:
        return "BOOLEAN_TYPE";
      case XPathResult.NUMBER_TYPE:
        return "NUMBER_TYPE";
      case XPathResult.STRING_TYPE:
        return "STRING_TYPE";
      case XPathResult.FIRST_ORDERED_NODE_TYPE:
        return "FIRST_ORDERED_NODE_TYPE";
      case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
        return "ORDERED_NODE_ITERATOR_TYPE";
      case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
        return "ORDERED_NODE_SNAPSHOT_TYPE";
      case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
        return "UNORDERED_NODE_ITERATOR_TYPE";
      case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
        return "UNORDERED_NODE_SNAPSHOT_TYPE";
      default:
        return "(unknown)";
      }
  }

}
