/*

 */

/*

 * 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.patterns;

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.XObject;

/**

 * This class represents a union pattern, which can have multiple individual

 * StepPattern patterns.

 * @xsl.usage advanced

 */

public class UnionPattern extends Expression

{

    static final long serialVersionUID = -6670449967116905820L;

  /** Array of the contained step patterns to be tested.

   *  @serial  */

  private StepPattern[] m_patterns;

  /**

   * No arguments to process, so this does nothing.

   */

  {

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

    {

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

    }

  }

  /**

   * Tell if this expression or it's subexpressions can traverse outside

   * the current subtree.

   *

   * @return true if traversal outside the context node's subtree can occur.

   */

   public boolean canTraverseOutsideSubtree()

   {

     if(null != m_patterns)

     {

      int n = m_patterns.length;

      for (int i = 0; i < n; i++)

      {

        if(m_patterns[i].canTraverseOutsideSubtree())

          return true;

      }

     }

     return false;

   }

  /**

   * Set the contained step patterns to be tested.

   *

   *

   * @param patterns the contained step patterns to be tested.

   */

  public void setPatterns(StepPattern[] patterns)

  {

    m_patterns = patterns;

    if(null != patterns)

    {

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

        {

                patterns[i].exprSetParent(this);

        }

    }

  }

  /**

   * Get the contained step patterns to be tested.

   *

   *

   * @return an array of the contained step patterns to be tested.

   */

  public StepPattern[] getPatterns()

  {

    return m_patterns;

  }

  /**

   * Test a node to see if it matches any of the patterns in the union.

   *

   * @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

  {

    XObject bestScore = null;

    int n = m_patterns.length;

    for (int i = 0; i < n; i++)

    {

      XObject score = m_patterns[i].execute(xctxt);

      if (score != NodeTest.SCORE_NONE)

      {

        if (null == bestScore)

          bestScore = score;

        else if (score.num() > bestScore.num())

          bestScore = score;

      }

    }

    if (null == bestScore)

    {

      bestScore = NodeTest.SCORE_NONE;

    }

    return bestScore;

  }

  class UnionPathPartOwner implements ExpressionOwner

  {

        int m_index;

        UnionPathPartOwner(int index)

        {

                m_index = index;

        }

    /**

     * @see ExpressionOwner#getExpression()

     */

    public Expression getExpression()

    {

      return m_patterns[m_index];

    }

    /**

     * @see ExpressionOwner#setExpression(Expression)

     */

    public void setExpression(Expression exp)

    {

        exp.exprSetParent(UnionPattern.this);

        m_patterns[m_index] = (StepPattern)exp;

    }

  }

  /**

   * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)

   */

  public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)

  {

        visitor.visitUnionPattern(owner, this);

        if(null != m_patterns)

        {

                int n = m_patterns.length;

                for(int i = 0; i < n; i++)

                {

                        m_patterns[i].callVisitors(new UnionPathPartOwner(i), visitor);

                }

        }

  }

  /**

   * @see Expression#deepEquals(Expression)

   */

  public boolean deepEquals(Expression expr)

  {

        if(!isSameClass(expr))

                return false;

        UnionPattern up = (UnionPattern)expr;

        if(null != m_patterns)

        {

                int n = m_patterns.length;

                if((null == up.m_patterns) || (up.m_patterns.length != n))

                        return false;

                for(int i = 0; i < n; i++)

                {

                        if(!m_patterns[i].deepEquals(up.m_patterns[i]))

                                return false;

                }

        }

        else if(up.m_patterns != null)

                return false;

        return true;

  }

}