/*

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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.

 */

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

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

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

import com.sun.org.apache.xpath.internal.objects.XObject;

import com.sun.org.apache.xpath.internal.patterns.NodeTest;

/**

 * This class defines a simplified type of union iterator that only

 * tests along the child axes.  If the conditions are right, it is

 * much faster than using a UnionPathIterator.

 */

public class UnionChildIterator extends ChildTestIterator

{

    static final long serialVersionUID = 3500298482193003495L;

  /**

   * Even though these may hold full LocPathIterators, this array does

   * not have to be cloned, since only the node test and predicate

   * portion are used, and these only need static information.  However,

   * also note that index predicates can not be used!

   */

  private PredicatedNodeTest[] m_nodeTests = null;

  /**

   * Constructor for UnionChildIterator

   */

  public UnionChildIterator()

  {

    super(null);

  }

  /**

   * Add a node test to the union list.

   *

   * @param test reference to a NodeTest, which will be added

   * directly to the list of node tests (in other words, it will

   * not be cloned).  The parent of this test will be set to

   * this object.

   */

  public void addNodeTest(PredicatedNodeTest test)

  {

    // Increase array size by only 1 at a time.  Fix this

    // if it looks to be a problem.

    if (null == m_nodeTests)

    {

      m_nodeTests = new PredicatedNodeTest[1];

      m_nodeTests[0] = test;

    }

    else

    {

      PredicatedNodeTest[] tests = m_nodeTests;

      int len = m_nodeTests.length;

      m_nodeTests = new PredicatedNodeTest[len + 1];

      System.arraycopy(tests, 0, m_nodeTests, 0, len);

      m_nodeTests[len] = test;

    }

    test.exprSetParent(this);

  }

  /**

   * This function is used to fixup variables from QNames to stack frame

   * indexes at stylesheet build time.

   * @param vars List of QNames that correspond to variables.  This list

   * should be searched backwards for the first qualified name that

   * corresponds to the variable reference qname.  The position of the

   * QName in the vector from the start of the vector will be its position

   * in the stack frame (but variables above the globalsTop value will need

   * to be offset to the current stack frame).

   */

  {

    super.fixupVariables(vars, globalsSize);

    if (m_nodeTests != null) {

      for (int i = 0; i < m_nodeTests.length; i++) {

        m_nodeTests[i].fixupVariables(vars, globalsSize);

      }

    }

  }

  /**

   * Test whether a specified node is visible in the logical view of a

   * TreeWalker or NodeIterator. This function will be called by the

   * implementation of TreeWalker and NodeIterator; it is not intended to

   * be called directly from user code.

   * @param n  The node to check to see if it passes the filter or not.

   * @return  a constant to determine whether the node is accepted,

   *   rejected, or skipped, as defined  above .

   */

  public short acceptNode(int n)

  {

    XPathContext xctxt = getXPathContext();

    try

    {

      xctxt.pushCurrentNode(n);

      for (int i = 0; i < m_nodeTests.length; i++)

      {

        PredicatedNodeTest pnt = m_nodeTests[i];

        XObject score = pnt.execute(xctxt, n);

        if (score != NodeTest.SCORE_NONE)

        {

          // Note that we are assuming there are no positional predicates!

          if (pnt.getPredicateCount() > 0)

          {

            if (pnt.executePredicates(n, xctxt))

              return DTMIterator.FILTER_ACCEPT;

          }

          else

            return DTMIterator.FILTER_ACCEPT;

        }

      }

    }

    catch (javax.xml.transform.TransformerException se)

    {

      // TODO: Fix this.

      throw new RuntimeException(se.getMessage());

    }

    finally

    {

      xctxt.popCurrentNode();

    }

    return DTMIterator.FILTER_SKIP;

  }

}