/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/*

 * Copyright 1999-2004 The Apache Software Foundation.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

/*

 * $Id: XRTreeFrag.java,v 1.2.4.1 2005/09/14 20:44:48 jeffsuttor Exp $

 */

package com.sun.org.apache.xpath.internal.objects;

import com.sun.org.apache.xml.internal.dtm.DTM;

import com.sun.org.apache.xml.internal.dtm.DTMIterator;

import com.sun.org.apache.xml.internal.utils.XMLString;

import com.sun.org.apache.xpath.internal.Expression;

import com.sun.org.apache.xpath.internal.ExpressionNode;

import com.sun.org.apache.xpath.internal.XPathContext;

import com.sun.org.apache.xpath.internal.axes.RTFIterator;

import org.w3c.dom.NodeList;

/**

 * This class represents an XPath result tree fragment object, and is capable of

 * converting the RTF to other types, such as a string.

 * @xsl.usage general

 */

public class XRTreeFrag extends XObject implements Cloneable

{

    static final long serialVersionUID = -3201553822254911567L;

  private DTMXRTreeFrag m_DTMXRTreeFrag;

  private int m_dtmRoot = DTM.NULL;

  protected boolean m_allowRelease = false;

  /**

   * Create an XRTreeFrag Object.

   *

   */

  public XRTreeFrag(int root, XPathContext xctxt, ExpressionNode parent)

  {

    super(null);

    exprSetParent(parent);

    initDTM(root, xctxt);

  }

  /**

   * Create an XRTreeFrag Object.

   *

   */

  public XRTreeFrag(int root, XPathContext xctxt)

  {

    super(null);

   initDTM(root, xctxt);

  }

  private final void initDTM(int root, XPathContext xctxt){

    m_dtmRoot = root;

    final DTM dtm = xctxt.getDTM(root);

    if(dtm != null){

      m_DTMXRTreeFrag = xctxt.getDTMXRTreeFrag(xctxt.getDTMIdentity(dtm));

    }

  }

  /**

   * Return a java object that's closest to the representation

   * that should be handed to an extension.

   *

   * @return The object that this class wraps

   */

  public Object object()

  {

    if (m_DTMXRTreeFrag.getXPathContext() != null)

      return new com.sun.org.apache.xml.internal.dtm.ref.DTMNodeIterator((DTMIterator)(new com.sun.org.apache.xpath.internal.NodeSetDTM(m_dtmRoot, m_DTMXRTreeFrag.getXPathContext().getDTMManager())));

    else

      return super.object();

  }

  /**

   * Create an XRTreeFrag Object.

   *

   */

  public XRTreeFrag(Expression expr)

  {

    super(expr);

  }

  /**

   * Specify if it's OK for detach to release the iterator for reuse.

   *

   * @param allowRelease true if it is OK for detach to release this iterator

   * for pooling.

   */

  public void allowDetachToRelease(boolean allowRelease)

  {

    m_allowRelease = allowRelease;

  }

  /**

   * Detaches the <code>DTMIterator</code> from the set which it iterated

   * over, releasing any computational resources and placing the iterator

   * in the INVALID state. After <code>detach</code> has been invoked,

   * calls to <code>nextNode</code> or <code>previousNode</code> will

   * raise a runtime exception.

   *

   * In general, detach should only be called once on the object.

   */

  public void detach(){

    if(m_allowRelease){

        m_DTMXRTreeFrag.destruct();

      setObject(null);

    }

  }

  /**

   * Tell what kind of class this is.

   *

   * @return type CLASS_RTREEFRAG

   */

  public int getType()

  {

    return CLASS_RTREEFRAG;

  }

  /**

   * Given a request type, return the equivalent string.

   * For diagnostic purposes.

   *

   * @return type string "#RTREEFRAG"

   */

  public String getTypeString()

  {

    return "#RTREEFRAG";

  }

  /**

   * Cast result object to a number.

   *

   * @return The result tree fragment as a number or NaN

   */

  public double num()

    throws javax.xml.transform.TransformerException

  {

    XMLString s = xstr();

    return s.toDouble();

  }

  /**

   * Cast result object to a boolean.  This always returns true for a RTreeFrag

   * because it is treated like a node-set with a single root node.

   *

   * @return true

   */

  public boolean bool()

  {

    return true;

  }

  private XMLString m_xmlStr = null;

  /**

   * Cast result object to an XMLString.

   *

   * @return The document fragment node data or the empty string.

   */

  public XMLString xstr()

  {

    if(null == m_xmlStr)

      m_xmlStr = m_DTMXRTreeFrag.getDTM().getStringValue(m_dtmRoot);

    return m_xmlStr;

  }

  /**

   * Cast result object to a string.

   *

   * @return The string this wraps or the empty string if null

   */

  public void appendToFsb(com.sun.org.apache.xml.internal.utils.FastStringBuffer fsb)

  {

    XString xstring = (XString)xstr();

    xstring.appendToFsb(fsb);

  }

  /**

   * Cast result object to a string.

   *

   * @return The document fragment node data or the empty string.

   */

  public String str()

  {

    String str = m_DTMXRTreeFrag.getDTM().getStringValue(m_dtmRoot).toString();

    return (null == str) ? "" : str;

  }

  /**

   * Cast result object to a result tree fragment.

   *

   * @return The document fragment this wraps

   */

  public int rtf()

  {

    return m_dtmRoot;

  }

  /**

   * Cast result object to a DTMIterator.

   * dml - modified to return an RTFIterator for

   * benefit of EXSLT object-type function in

   * {@link com.sun.org.apache.xalan.internal.lib.ExsltCommon}.

   * @return The document fragment as a DTMIterator

   */

  public DTMIterator asNodeIterator()

  {

    return new RTFIterator(m_dtmRoot, m_DTMXRTreeFrag.getXPathContext().getDTMManager());

  }

  /**

   * Cast result object to a nodelist. (special function).

   *

   * @return The document fragment as a nodelist

   */

  public NodeList convertToNodeset()

  {

    if (m_obj instanceof NodeList)

      return (NodeList) m_obj;

    else

      return new com.sun.org.apache.xml.internal.dtm.ref.DTMNodeList(asNodeIterator());

  }

  /**

   * Tell if two objects are functionally equal.

   *

   * @param obj2 Object to compare this to

   *

   * @return True if the two objects are equal

   *

   * @throws javax.xml.transform.TransformerException

   */

  public boolean equals(XObject obj2)

  {

    try

    {

      if (XObject.CLASS_NODESET == obj2.getType())

      {

        // In order to handle the 'all' semantics of

        // nodeset comparisons, we always call the

        // nodeset function.

        return obj2.equals(this);

      }

      else if (XObject.CLASS_BOOLEAN == obj2.getType())

      {

        return bool() == obj2.bool();

      }

      else if (XObject.CLASS_NUMBER == obj2.getType())

      {

        return num() == obj2.num();

      }

      else if (XObject.CLASS_NODESET == obj2.getType())

      {

        return xstr().equals(obj2.xstr());

      }

      else if (XObject.CLASS_STRING == obj2.getType())

      {

        return xstr().equals(obj2.xstr());

      }

      else if (XObject.CLASS_RTREEFRAG == obj2.getType())

      {

        // Probably not so good.  Think about this.

        return xstr().equals(obj2.xstr());

      }

      else

      {

        return super.equals(obj2);

      }

    }

    catch(javax.xml.transform.TransformerException te)

    {

      throw new com.sun.org.apache.xml.internal.utils.WrappedRuntimeException(te);

    }

  }

}