source: NonGTP/Xerces/xerces/include/xercesc/framework/XMLGrammarPool.hpp @ 358

/*
 * 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.
 */

/*
 * $Log: XMLGrammarPool.hpp,v $
 * Revision 1.14  2004/09/29 19:27:07  cargilld
 * Fix for Jira-1217: fixing problems with getXSModel.
 *
 * Revision 1.13  2004/09/08 13:55:59  peiyongz
 * Apache License Version 2.0
 *
 * Revision 1.12  2004/04/07 14:09:22  peiyongz
 * systemId (to replace rootElemName) as DTDGrammar Key
 *
 * Revision 1.11  2003/11/25 15:10:44  jberry
 * Eliminate some compiler warnings concerning comments inside of comments
 *
 * Revision 1.10  2003/11/21 22:34:45  neilg
 * More schema component model implementation, thanks to David Cargill.
 * In particular, this cleans up and completes the XSModel, XSNamespaceItem,
 * XSAttributeDeclaration and XSAttributeGroup implementations.
 *
 * Revision 1.9  2003/11/06 21:53:52  neilg
 * update grammar pool interface so that cacheGrammar(Grammar) can tell the caller whether the grammar was accepted.  Also fix some documentation errors.
 *
 * Revision 1.8  2003/11/06 15:30:06  neilg
 * first part of PSVI/schema component model implementation, thanks to David Cargill.  This covers setting the PSVIHandler on parser objects, as well as implementing XSNotation, XSSimpleTypeDefinition, XSIDCDefinition, and most of XSWildcard, XSComplexTypeDefinition, XSElementDeclaration, XSAttributeDeclaration and XSAttributeUse.
 *
 * Revision 1.7  2003/11/05 18:19:09  peiyongz
 * Documentation update
 *
 * Revision 1.6  2003/10/29 16:16:48  peiyongz
 * GrammarPool' serialization/deserialization support
 *
 * Revision 1.5  2003/10/10 18:36:03  neilg
 * update XMLGrammarPool interface to make expected behaviour of locked pools better specified, and to add the capability to generate XSModels
 *
 * Revision 1.4  2003/09/16 18:30:54  neilg
 * make Grammar pool be responsible for creating and owning URI string pools.  This is one more step towards having grammars be independent of the parsers involved in their creation
 *
 * Revision 1.3  2003/09/02 08:59:02  gareth
 * Added API to get enumerator of grammars.
 *
 * Revision 1.2  2003/07/31 17:02:42  peiyongz
 * Grammar embed GrammarDescription
 *
 * Revision 1.1  2003/06/20 18:37:39  peiyongz
 * Stateless Grammar Pool :: Part I
 *
 * $Id: XMLGrammarPool.hpp,v 1.14 2004/09/29 19:27:07 cargilld Exp $
 *
 */

#if !defined(XMLGRAMMARPOOL_HPP)
#define XMLGRAMMARPOOL_HPP

#include <xercesc/util/PlatformUtils.hpp>
#include <xercesc/util/RefHashTableOf.hpp>
#include <xercesc/util/XMemory.hpp>
#include <xercesc/framework/psvi/XSModel.hpp>


XERCES_CPP_NAMESPACE_BEGIN

class Grammar;
class XMLGrammarDescription;
class DTDGrammar;
class SchemaGrammar;
class XMLDTDDescription;
class XMLSchemaDescription;
class XMLStringPool;
class BinInputStream;
class BinOutputStream;

class XMLPARSER_EXPORT XMLGrammarPool : public XMemory
{
public :
    // -----------------------------------------------------------------------
    /** @name Virtual destructor for derived classes */
    // -----------------------------------------------------------------------
    //@{

    /**
      * virtual destructor
      *
      */
    virtual ~XMLGrammarPool(){};
    //@}

    // -----------------------------------------------------------------------
    /** @name The Grammar Pool Interface */
    // -----------------------------------------------------------------------
    //@{

    /**
      * cacheGrammar
      *
      * Provide the grammar pool with an opportunity
      * to cache the given grammar.  If the pool does not choose to do so,
      * it should return false; otherwise, it should return true, so that
      * the caller knows whether the grammar has been adopted.
      *
      * @param gramToCache: the Grammar to be cached in the grammar pool
      * @return true if the grammar pool has elected to cache the grammar (in which case
      * it is assumed to have adopted it); false if it does not cache it
          *
      */
    virtual bool           cacheGrammar(Grammar* const               gramToCache) = 0;
    
    /**
      * retrieveGrammar
      *
      * @param gramDesc: the Grammar Description used to search for grammar
          *                  cached in the grammar pool
          *
      */
    virtual Grammar*       retrieveGrammar(XMLGrammarDescription* const gramDesc) = 0;
    
        
    /**
      * orphanGrammar
      *
      * grammar removed from the grammar pool and owned by the caller
      *
      * @param nameSpaceKey: Key used to search for grammar in the grammar pool
      * @return the grammar that was removed from the pool (0 if none)
      */
    virtual Grammar*       orphanGrammar(const XMLCh* const nameSpaceKey) = 0;  


    /**
     * Get an enumeration of the cached Grammars in the Grammar pool
     *
     * @return enumeration of the cached Grammars in Grammar pool
     */
    virtual RefHashTableOfEnumerator<Grammar> getGrammarEnumerator() const = 0;

    /**
      * clear
      *
      * all grammars are removed from the grammar pool and deleted.
      * @return true if the grammar pool was cleared. false if it did not.
      */
    virtual bool           clear() = 0;
        
    /**
      * lockPool
      *
          * When this method is called by the application, the 
      * grammar pool should stop adding new grammars to the cache.
      * This should result in the grammar pool being sharable
      * among parsers operating in different threads.
      *
      */
    virtual void           lockPool() = 0;
    
    /**
      * unlockPool
      *
          * After this method has been called, the grammar pool implementation
      * should return to its default behaviour when cacheGrammars(...) is called.
      * One effect, depending on the underlying implementation, is that the grammar pool
      * may no longer be thread-safe (even on read operations).
      *
      * For PSVI support any previous XSModel that was produced will be deleted.
      */
    virtual void           unlockPool() = 0;

    //@}

    // -----------------------------------------------------------------------
    /** @name  Factory interface */
    // -----------------------------------------------------------------------
    //@{

    /**
      * createDTDGrammar
      *
      */
    virtual DTDGrammar*            createDTDGrammar() = 0;

    /**
      * createSchemaGrammar
      *
      */
    virtual SchemaGrammar*         createSchemaGrammar() = 0;
                    
    /**
      * createDTDDescription
      *
      */        
    virtual XMLDTDDescription*     createDTDDescription(const XMLCh* const systemId) = 0;
    /**
      * createSchemaDescription
      *
      */                
    virtual XMLSchemaDescription*  createSchemaDescription(const XMLCh* const targetNamespace) = 0;

    //@}

    // -----------------------------------------------------------------------
    /** @name  schema component model support */
    // -----------------------------------------------------------------------                                                        
    //@{

    /***
      * Return an XSModel derived from the components of all SchemaGrammars
      * in the grammar pool.  If the pool is locked, this should
      * be a thread-safe operation.  It should return null if and only if
      * the pool is empty.
      *
      * Calling getXSModel() on an unlocked grammar pool may result in the
      * creation of a new XSModel with the old XSModel being deleted.  The
      * function will return a different address for the XSModel if it has
      * changed.
      * 
      * @deprecated (shouldn't use address to determine if XSModel changed)
      */
    virtual XSModel *getXSModel() = 0;

    /***
      * Return an XSModel derived from the components of all SchemaGrammars
      * in the grammar pool.  If the pool is locked, this should
      * be a thread-safe operation.
      *
      * NOTE: The function should NEVER return NULL.  If there are no grammars in
      *       the pool it should return an XSModel containing the Schema for Schema.      
      *
      * Calling getXSModel() on an unlocked grammar pool may result in the
      * creation of a new XSModel with the old XSModel being deleted.
      * The bool parameter will indicate if the XSModel was changed.
      *     
      * For source code compatibility, default implementation is to say
      * XSModelWasChanged.
      */
    virtual XSModel *getXSModel(bool& XSModelWasChanged)
    {
        XSModelWasChanged = true;
        return getXSModel();
    }
        
    // @}

    // -----------------------------------------------------------------------
    /** @name  Getter */
    // -----------------------------------------------------------------------                                                        
    //@{

    /**
      * getMemoryManager
      *
      */    
        inline MemoryManager* const    getMemoryManager()
    {
        return fMemMgr;
    }

    /**
      * Return an XMLStringPool for use by validation routines.  
      * Implementations should not create a string pool on each call to this
      * method, but should maintain one string pool for all grammars
      * for which this pool is responsible.
      */
    virtual XMLStringPool *getURIStringPool() = 0;
    //@}

    // -----------------------------------------------------------------------
    /** serialization and deserialization support */
    // -----------------------------------------------------------------------                                                        

    /***
      *
      * 1. Context: Serialize/Deserialize All Grammars In One Session
      *
      *    Since it is common that a declaration in one grammar may reference 
      *    to definitions in other grammars, it is required to serialize those 
      *    related (or interdependent) grammars in to one persistent data store 
      *    in one serialization session (storing), and deserialize them from the
      *    persistent data store in one deserialization session (loading) back
      *    to the grammar pool.    
      *
      * 2. Multiple serializations
      *
      *    It is acceptable that client application requests more than one 
      *    grammar serialization on a particular grammar pool, to track the 
      *    different grammars cached, or for whatever reasons that client 
      *    application is interested in. 
      *
      * 3. Multiple deserializations
      * 
      *    Request for grammar deserialization either after the grammar pool has 
      *    its own cached grammars, or request for more than one grammar 
      *    deserialization, may cause undesired and unpredictable consequence
      *    and therefore client application shall be aware that individual 
      *    implementationis may NOT support this.
      *
      *    However it is strongly recommended that the client application requests 
      *    no more than one grammar deserialization even a particular implementation
      *    may allow multiple deserializations.
      *
      * 4. Locking
      *
      *    Both serialization and deserialization requires to lock the grammar pool
      *    before operation and unlock after operation. In the case the grammar pool
      *    is locked by a third party, the request for serialization/deserialization
      *    will NOT be entertained.
      *
      * 5. Versioning
      *
      *    The Persistent data store has a version tag to be verified during 
      *    deserialization, thus a grammar pool may decide if it supports
      *    a binary data created by a different release of Xerces.
      * 
      * 6. Clean up
      *
      *    The client application shall be aware that in the event of an exception
      *    thrown due to a corrupted data store during deserialization, implementation
      *    may not be able to clean up all resources allocated, and therefore it is 
      *    client application's responsibility to clean up those unreleased resources.
      *
      *
      */
    virtual void     serializeGrammars(BinOutputStream* const)  = 0; 
    virtual void     deserializeGrammars(BinInputStream* const) = 0;       
           
protected :
    // -----------------------------------------------------------------------
    /**  Hidden Constructors */
    // -----------------------------------------------------------------------
    //@{
    XMLGrammarPool(MemoryManager* const memMgr = XMLPlatformUtils::fgMemoryManager)
    :fMemMgr(memMgr)
    {
    };
    //@}

private :
    // -----------------------------------------------------------------------
    /** name  Unimplemented copy constructor and operator= */
    // -----------------------------------------------------------------------
    //@{
    XMLGrammarPool(const XMLGrammarPool& );
    XMLGrammarPool& operator=(const XMLGrammarPool& );
    //@}

    // -----------------------------------------------------------------------
    //
    // fMemMgr: plugged-in (or defaulted-in) memory manager
    //          not owned 
    //          no reset after initialization
    //
    // -----------------------------------------------------------------------
    
    MemoryManager* const  fMemMgr;

};

XERCES_CPP_NAMESPACE_END

#endif