/*
* Copyright 1999-2002,2004 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.
*/
package org.apache.xerces.impl.dtd.models;
import org.apache.xerces.xni.QName;
import org.apache.xerces.impl.dtd.XMLContentSpec;
/**
* 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.
*
* @xerces.internal
*
* @version $Id: SimpleContentModel.java 320090 2004-10-04 22:00:42Z mrglavas $
*/
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 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 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 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.
*
*/
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