Java example source code file (FunctionPattern.java)

This example Java source code file (FunctionPattern.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

dtmiterator, expression, expressionowner, functionowner, functionpattern, score_none, score_other, steppattern, xnumber, xobject

The FunctionPattern.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: FunctionPattern.java,v 1.2.4.2 2005/09/15 00:21:15 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.patterns;

import com.sun.org.apache.xml.internal.dtm.DTM;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xpath.internal.Expression;
import com.sun.org.apache.xpath.internal.ExpressionOwner;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.XPathVisitor;
import com.sun.org.apache.xpath.internal.objects.XNumber;
import com.sun.org.apache.xpath.internal.objects.XObject;

/**
 * Match pattern step that contains a function.
 * @xsl.usage advanced
 */
public class FunctionPattern extends StepPattern
{
    static final long serialVersionUID = -5426793413091209944L;

  /**
   * Construct a FunctionPattern from a
   * {@link com.sun.org.apache.xpath.internal.functions.Function expression}.
   *
   * NEEDSDOC @param expr
   */
  public FunctionPattern(Expression expr, int axis, int predaxis)
  {

    super(0, null, null, axis, predaxis);

    m_functionExpr = expr;
  }

  /**
   * Static calc of match score.
   */
  public final void calcScore()
  {

    m_score = SCORE_OTHER;

    if (null == m_targetString)
      calcTargetString();
  }

  /**
   * Should be a {@link com.sun.org.apache.xpath.internal.functions.Function expression}.
   *  @serial
   */
  Expression m_functionExpr;

  /**
   * 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).
   */
  public void fixupVariables(java.util.Vector vars, int globalsSize)
  {
    super.fixupVariables(vars, globalsSize);
    m_functionExpr.fixupVariables(vars, globalsSize);
  }


  /**
   * Test a node to see if it matches the given node test.
   *
   * @param xctxt XPath runtime context.
   *
   * @return {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NODETEST},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NONE},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NSWILD},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_QNAME}, or
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_OTHER}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt, int context)
          throws javax.xml.transform.TransformerException
  {

    DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
    XNumber score = SCORE_NONE;

    if (null != nl)
    {
      int n;

      while (DTM.NULL != (n = nl.nextNode()))
      {
        score = (n == context) ? SCORE_OTHER : SCORE_NONE;

        if (score == SCORE_OTHER)
        {
          context = n;

          break;
        }
      }

      // nl.detach();
    }
    nl.detach();

    return score;
  }

  /**
   * Test a node to see if it matches the given node test.
   *
   * @param xctxt XPath runtime context.
   *
   * @return {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NODETEST},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NONE},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NSWILD},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_QNAME}, or
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_OTHER}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt, int context,
                         DTM dtm, int expType)
          throws javax.xml.transform.TransformerException
  {

    DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
    XNumber score = SCORE_NONE;

    if (null != nl)
    {
      int n;

      while (DTM.NULL != (n = nl.nextNode()))
      {
        score = (n == context) ? SCORE_OTHER : SCORE_NONE;

        if (score == SCORE_OTHER)
        {
          context = n;

          break;
        }
      }

      nl.detach();
    }

    return score;
  }

  /**
   * Test a node to see if it matches the given node test.
   *
   * @param xctxt XPath runtime context.
   *
   * @return {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NODETEST},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NONE},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_NSWILD},
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_QNAME}, or
   *         {@link com.sun.org.apache.xpath.internal.patterns.NodeTest#SCORE_OTHER}.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt)
          throws javax.xml.transform.TransformerException
  {

    int context = xctxt.getCurrentNode();
    DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
    XNumber score = SCORE_NONE;

    if (null != nl)
    {
      int n;

      while (DTM.NULL != (n = nl.nextNode()))
      {
        score = (n == context) ? SCORE_OTHER : SCORE_NONE;

        if (score == SCORE_OTHER)
        {
          context = n;

          break;
        }
      }

      nl.detach();
    }

    return score;
  }

  class FunctionOwner implements ExpressionOwner
  {
    /**
     * @see ExpressionOwner#getExpression()
     */
    public Expression getExpression()
    {
      return m_functionExpr;
    }


    /**
     * @see ExpressionOwner#setExpression(Expression)
     */
    public void setExpression(Expression exp)
    {
        exp.exprSetParent(FunctionPattern.this);
        m_functionExpr = exp;
    }
  }

  /**
   * Call the visitor for the function.
   */
  protected void callSubtreeVisitors(XPathVisitor visitor)
  {
    m_functionExpr.callVisitors(new FunctionOwner(), visitor);
    super.callSubtreeVisitors(visitor);
  }

}