content: /*
   * 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 mf.org.apache.xerces.impl.dtd.models;
  
  import mf.org.apache.xerces.impl.dtd.XMLContentSpec;
  import mf.org.apache.xerces.xni.QName;
  
  
  /**
   * SimpleContentModel is a derivative of the abstract content model base
   * class that handles a small set of simple content models that are just
   * way overkill to give the DFA treatment.
   * <p/>
   * This class handles the following scenarios:
   * <ul>
   * <li> a
   * <li> a?
   * <li> a*
   * <li> a+
   * <li> a,b
   * <li> a|b
   * </ul>
   * <p/>
   * These all involve a unary operation with one element type, or a binary
   * operation with two elements. These are very simple and can be checked
   * in a simple way without a DFA and without the overhead of setting up a
   * DFA for such a simple check.
   *
   * @version $Id: SimpleContentModel.java 699892 2008-09-28 21:08:27Z mrglavas $
   * @xerces.internal
   */
  public class SimpleContentModel
          implements ContentModelValidator {
  
      //
      // Constants
      //
  
      /**
       * CHOICE
       */
      public static final short CHOICE = -1;
  
      /**
       * SEQUENCE
       */
      public static final short SEQUENCE = -1;
  
      //
      // Data
      //
  
  
      /**
       * The element decl pool indices of the first (and optional second)
       * child node. The operation code tells us whether the second child
       * is used or not.
       */
      private final QName fFirstChild = new QName();
  
      /**
       * The element decl pool indices of the first (and optional second)
       * child node. The operation code tells us whether the second child
       * is used or not.
       */
      private final QName fSecondChild = new QName();
  
      /**
       * The operation that this object represents. Since this class only
       * does simple contents, there is only ever a single operation
       * involved (i.e. the children of the operation are always one or
       * two leafs.) This is one of the XMLDTDParams.CONTENTSPECNODE_XXX values.
       */
      private final int fOperator;
  
      /* this is the EquivClassComparator object */
      //private EquivClassComparator comparator = null;
  
  
      //
      // Constructors
      //
  
      /**
       * Constructs a simple content model.
       *
       * @param operator    The content model operator.
       * @param firstChild  qualified name of the first child
       * @param secondChild qualified name of the second child
       */
      public SimpleContentModel(short operator, QName firstChild, QName secondChild) {
          //
          //  Store away the children and operation. This is all we need to
          //  do the content model check.
          //
          //  The operation is one of the ContentSpecNode.NODE_XXX values!
          //
          fFirstChild.setValues(firstChild);
          if (secondChild != null) {
              fSecondChild.setValues(secondChild);
          } else {
              fSecondChild.clear();
          }
          fOperator = operator;
      }
  
      //
      // ContentModelValidator methods
      //
  
      /**
       * Check that the specified content is valid according to this
       * content model. This method can also be called to do 'what if'
       * testing of content models just to see if they would be valid.
       * <p/>
       * A value of -1 in the children array indicates a PCDATA node. All other
       * indexes will be positive and represent child elements. The count can be
       * zero, since some elements have the EMPTY content model and that must be
       * confirmed.
       *
       * @param children The children of this element.  Each integer is an index within
       *                 the <code>StringPool</code> of the child element name.  An index
       *                 of -1 is used to indicate an occurrence of non-whitespace character
       *                 data.
       * @param offset   Offset into the array where the children starts.
       * @param length   The number of entries in the <code>children</code> array.
       * @return The value -1 if fully valid, else the 0 based index of the child
       * that first failed. If the value returned is equal to the number
       * of children, then the specified children are valid but additional
       * content is required to reach a valid ending state.
       */
      @Override
      public int validate(QName[] children, int offset, int length) {
  
          //
          //  According to the type of operation, we do the correct type of
          //  content check.
          //
          switch (fOperator) {
              case XMLContentSpec.CONTENTSPECNODE_LEAF:
                  // If there is not a child, then report an error at index 0
                  if (length == 0)
                      return 0;
  
                  // If the 0th child is not the right kind, report an error at 0
                  if (children[offset].rawname != fFirstChild.rawname) {
                      return 0;
                  }
  
                  // If more than one child, report an error at index 1
                  if (length > 1)
                      return 1;
                  break;
  
              case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE:
                  //
                  //  If there is one child, make sure its the right type. If not,
                  //  then its an error at index 0.
                  //
                  if (length == 1) {
                      if (children[offset].rawname != fFirstChild.rawname) {
                          return 0;
                      }
                  }
  
                  //
                  //  If the child count is greater than one, then obviously
                  //  bad, so report an error at index 1.
                  //
                  if (length > 1)
                      return 1;
                  break;
  
              case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE:
                  //
                  //  If the child count is zero, that's fine. If its more than
                  //  zero, then make sure that all children are of the element
                  //  type that we stored. If not, report the index of the first
                  //  failed one.
                  //
                  if (length > 0) {
                      for (int index = 0; index < length; index++) {
                          if (children[offset + index].rawname != fFirstChild.rawname) {
                              return index;
                          }
                      }
                  }
                  break;
  
              case XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE:
                  //
                  //  If the child count is zero, that's an error so report
                  //  an error at index 0.
                  //
                  if (length == 0)
                      return 0;
  
                  //
                  //  Otherwise we have to check them all to make sure that they
                  //  are of the correct child type. If not, then report the index
                  //  of the first one that is not.
                  //
                  for (int index = 0; index < length; index++) {
                      if (children[offset + index].rawname != fFirstChild.rawname) {
                          return index;
                      }
                  }
                  break;
  
              case XMLContentSpec.CONTENTSPECNODE_CHOICE:
                  //
                  //  There must be one and only one child, so if the element count
                  //  is zero, return an error at index 0.
                  //
                  if (length == 0)
                      return 0;
  
                  // If the zeroth element isn't one of our choices, error at 0
                  if ((children[offset].rawname != fFirstChild.rawname) &&
                          (children[offset].rawname != fSecondChild.rawname)) {
                      return 0;
                  }
  
                  // If there is more than one element, then an error at 1
                  if (length > 1)
                      return 1;
                  break;
  
              case XMLContentSpec.CONTENTSPECNODE_SEQ:
                  //
                  //  There must be two children and they must be the two values
                  //  we stored, in the stored order.
                  //
                  if (length == 2) {
                      if (children[offset].rawname != fFirstChild.rawname) {
                          return 0;
                      }
                      if (children[offset + 1].rawname != fSecondChild.rawname) {
                          return 1;
                      }
                  } else {
                      if (length > 2) {
                          return 2;
                      }
  
                      return length;
                  }
  
                  break;
  
              default:
                  throw new RuntimeException("ImplementationMessages.VAL_CST");
          }
  
          // We survived, so return success status
          return -1;
      } // validate
  
  } // class SimpleContentModel
  