org.apache.xerces.impl.dtd.models
Class DFAContentModel

java.lang.Object
  |
  +--org.apache.xerces.impl.dtd.models.DFAContentModel

All Implemented Interfaces:

ContentModelValidator

public class DFAContentModel

extends java.lang.Object

implements ContentModelValidator

Version:

$Id: DFAContentModel.java,v 1.3 2002/01/29 01:15:10 lehors Exp $ DFAContentModel is the derivative of ContentModel that does all of the non-trivial element content validation. This class does the conversion from the regular expression to the DFA that it then uses in its validation algorithm.

Note: Upstream work insures that this class will never see a content model with PCDATA in it. Any model with PCDATA is 'mixed' and is handled via the MixedContentModel class since mixed models are very constrained in form and easily handled via a special case. This also makes implementation of this class much easier.

Constructor Summary

DFAContentModel(CMNode syntaxTree, int leafCount, boolean dtd, boolean mixed)
Constructs a DFA content model.

Method Summary

int	validate(org.apache.xerces.xni.QName[] children, int offset, int length) Check that the specified content is valid according to this content model.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DFAContentModel

public DFAContentModel(CMNode syntaxTree,
                       int leafCount,
                       boolean dtd,
                       boolean mixed)

Constructs a DFA content model.

Parameters:

syntaxTree - The syntax tree of the content model.

leafCount - The number of leaves.

dtd - if it is created for a DTDGrammar.

Method Detail

validate

public int validate(org.apache.xerces.xni.QName[] children,
                    int offset,
                    int length)

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.

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.

Specified by:

validate in interface ContentModelValidator

Parameters:

children - The children of this element. Each integer is an index within the StringPool of the child element name. An index of -1 is used to indicate an occurrence of non-whitespace character data.

offset - Offset into the array where the children starts.

length - The number of entries in the children array.

Returns:

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.