Java example source code file (BasicTestIterator.java)

This example Java source code file (BasicTestIterator.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

basictestiterator, childtestiterator, clonenotsupportedexception, compiler, dtmiterator, locpathiterator

The BasicTestIterator.java Java example source code

/*
 * 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: BasicTestIterator.java,v 1.2.4.1 2005/09/14 19:45:20 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.axes;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMFilter;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xpath.internal.compiler.Compiler;
import com.sun.org.apache.xpath.internal.compiler.OpMap;

/**
 * Base for iterators that handle predicates.  Does the basic next
 * node logic, so all the derived iterator has to do is get the
 * next node.
 */
public abstract class BasicTestIterator extends LocPathIterator
{
    static final long serialVersionUID = 3505378079378096623L;
  /**
   * Create a LocPathIterator object.
   *
   * @param nscontext The namespace context for this iterator,
   * should be OK if null.
   */
  protected BasicTestIterator()
  {
  }


  /**
   * Create a LocPathIterator object.
   *
   * @param nscontext The namespace context for this iterator,
   * should be OK if null.
   */
  protected BasicTestIterator(PrefixResolver nscontext)
  {

    super(nscontext);
  }

  /**
   * Create a LocPathIterator object, including creation
   * of step walkers from the opcode list, and call back
   * into the Compiler to create predicate expressions.
   *
   * @param compiler The Compiler which is creating
   * this expression.
   * @param opPos The position of this iterator in the
   * opcode list from the compiler.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected BasicTestIterator(Compiler compiler, int opPos, int analysis)
          throws javax.xml.transform.TransformerException
  {
    super(compiler, opPos, analysis, false);

    int firstStepPos = OpMap.getFirstChildPos(opPos);
    int whatToShow = compiler.getWhatToShow(firstStepPos);

    if ((0 == (whatToShow
               & (DTMFilter.SHOW_ATTRIBUTE
               | DTMFilter.SHOW_NAMESPACE
               | DTMFilter.SHOW_ELEMENT
               | DTMFilter.SHOW_PROCESSING_INSTRUCTION)))
               || (whatToShow == DTMFilter.SHOW_ALL))
      initNodeTest(whatToShow);
    else
    {
      initNodeTest(whatToShow, compiler.getStepNS(firstStepPos),
                              compiler.getStepLocalName(firstStepPos));
    }
    initPredicateInfo(compiler, firstStepPos);
  }

  /**
   * Create a LocPathIterator object, including creation
   * of step walkers from the opcode list, and call back
   * into the Compiler to create predicate expressions.
   *
   * @param compiler The Compiler which is creating
   * this expression.
   * @param opPos The position of this iterator in the
   * opcode list from the compiler.
   * @param shouldLoadWalkers True if walkers should be
   * loaded, or false if this is a derived iterator and
   * it doesn't wish to load child walkers.
   *
   * @throws javax.xml.transform.TransformerException
   */
  protected BasicTestIterator(
          Compiler compiler, int opPos, int analysis, boolean shouldLoadWalkers)
            throws javax.xml.transform.TransformerException
  {
    super(compiler, opPos, analysis, shouldLoadWalkers);
  }


  /**
   * Get the next node via getNextXXX.  Bottlenecked for derived class override.
   * @return The next node on the axis, or DTM.NULL.
   */
  protected abstract int getNextNode();

  /**
   *  Returns the next node in the set and advances the position of the
   * iterator in the set. After a NodeIterator is created, the first call
   * to nextNode() returns the first node in the set.
   *
   * @return  The next <code>Node in the set being iterated over, or
   *   <code>null if there are no more members in that set.
   */
  public int nextNode()
  {
        if(m_foundLast)
        {
                m_lastFetched = DTM.NULL;
                return DTM.NULL;
        }

    if(DTM.NULL == m_lastFetched)
    {
      resetProximityPositions();
    }

    int next;

    com.sun.org.apache.xpath.internal.VariableStack vars;
    int savedStart;
    if (-1 != m_stackFrame)
    {
      vars = m_execContext.getVarStack();

      // These three statements need to be combined into one operation.
      savedStart = vars.getStackFrame();

      vars.setStackFrame(m_stackFrame);
    }
    else
    {
      // Yuck.  Just to shut up the compiler!
      vars = null;
      savedStart = 0;
    }

    try
    {
      do
      {
        next = getNextNode();

        if (DTM.NULL != next)
        {
          if(DTMIterator.FILTER_ACCEPT == acceptNode(next))
            break;
          else
            continue;
        }
        else
          break;
      }
      while (next != DTM.NULL);

      if (DTM.NULL != next)
      {
        m_pos++;
        return next;
      }
      else
      {
        m_foundLast = true;

        return DTM.NULL;
      }
    }
    finally
    {
      if (-1 != m_stackFrame)
      {
        // These two statements need to be combined into one operation.
        vars.setStackFrame(savedStart);
      }
    }
  }

  /**
   *  Get a cloned Iterator that is reset to the beginning
   *  of the query.
   *
   *  @return A cloned NodeIterator set of the start of the query.
   *
   *  @throws CloneNotSupportedException
   */
  public DTMIterator cloneWithReset() throws CloneNotSupportedException
  {

    ChildTestIterator clone = (ChildTestIterator) super.cloneWithReset();

    clone.resetProximityPositions();

    return clone;
  }


}