/*
 * 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.
 */

/*
 * $Id: XMLGrammarPoolImpl.hpp 191668 2005-06-21 15:34:32Z cargilld $
 */

#if !defined(XMLGrammarPoolImplIMPL_HPP)
#define XMLGrammarPoolImplIMPL_HPP

#include <xercesc/framework/XMLGrammarPool.hpp>

XERCES_CPP_NAMESPACE_BEGIN

class XMLSynchronizedStringPool;

class XMLUTIL_EXPORT XMLGrammarPoolImpl : public XMLGrammarPool
{
public :
    // -----------------------------------------------------------------------
    /** @name constructor and destructor */
    // -----------------------------------------------------------------------
    //@{

    XMLGrammarPoolImpl(MemoryManager* const memMgr);

    ~XMLGrammarPoolImpl();
    //@}

    // -----------------------------------------------------------------------
    /** @name Implementation of 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);
    

    /**
      * retrieveGrammar
      *
      * @param gramDesc: the Grammar Description used to search for grammar
	  *                  cached in the grammar pool
	  *
      */
    virtual Grammar*       retrieveGrammar(XMLGrammarDescription* const gramDesc);
    
        
    /**
      * orphanGrammar
      *
	  * grammar removed from the grammar pool and owned by the caller
      *
      * @param nameSpaceKey: Key used to search for grammar in the grammar pool
	  *
      */
    virtual Grammar*       orphanGrammar(const XMLCh* const nameSpaceKey);  


    /**
     * 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;

    /**
      * 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();
        
    /**
      * lockPool
      *
	  * When this method is called by the application, the 
      * grammar pool should stop adding new grammars to the cache.
      */
    virtual void           lockPool();
    
    /**
      * unlockPool
      *
	  * After this method has been called, the grammar pool implementation
      * should return to its default behaviour when cacheGrammars(...) is called.
      *
      * For PSVI support any previous XSModel that was produced will be deleted.
      */
    virtual void           unlockPool();

    //@}

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

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

    /**
      * createSchemaGrammar
      *
      */
    virtual SchemaGrammar*         createSchemaGrammar();
                    
    /**
      * createDTDDescription
      *
      */	
    virtual XMLDTDDescription*     createDTDDescription(const XMLCh* const systemId);
    /**
      * createSchemaDescription
      *
      */		
    virtual XMLSchemaDescription*  createSchemaDescription(const XMLCh* const targetNamespace);
    //@}
	
    // -----------------------------------------------------------------------
    /** @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.
      *
      * In this implementation, when the pool is not locked a new XSModel will be
      * computed each this time the pool is called if the pool has changed (and the
      * previous one will be destroyed at that time).  When the lockPool()
      * method is called, an XSModel will be generated and returned whenever this method is called
      * while the pool is in the locked state.  This will be destroyed if the unlockPool()
      * operation is called.  The XSModel will not be serialized,
      * but will be recreated if a deserialized pool is in the 
      * locked state.
      *
      * @deprecated (shouldn't use address to determine if XSModel changed)
      */
    virtual XSModel *getXSModel();

    /***
      * 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.
      *  
      * In this implementation, when the pool is not locked a new XSModel will be
      * computed each this time the pool is called if the pool has changed (and the
      * previous one will be destroyed at that time).  When the lockPool()
      * method is called, an XSModel will be generated and returned whenever this method is called
      * while the pool is in the locked state.  This will be destroyed if the unlockPool()
      * operation is called.  The XSModel will not be serialized,
      * but will be recreated if a deserialized pool is in the 
      * locked state.
      *      
      */
    virtual XSModel *getXSModel(bool& XSModelWasChanged);

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

    /**
      * 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();

    // @}

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

    /***
      *
      * Multiple serializations
      *
      *    For multiple serializations, if the same file name is given, then the 
      *    last result will be in the file (overwriting mode), if different file 
      *    names are given, then there are multiple data stores for each serialization.
      *
      * Multiple deserializations
      * 
      *    Not supported
      *
      * Versioning
      *
      *    Only binary data serialized with the current XercesC Version and
      *    SerializationLevel is supported.
      *
      * Clean up
      *
      *    In the event of an exception thrown due to a corrupted data store during 
      *    deserialization, this implementation may not be able to clean up all resources 
      *    allocated, and therefore it is the client application's responsibility to 
      *    clean up those unreleased resources.
      *
      * Coupling of Grammars and StringPool
      *
      *    This implementation assumes that StringPool shall always be 
      *    serialized/deserialized together with the grammars. In the case that such a
      *    coupling is not desired, client application can modify this behaviour by 
      *    either derivate from this imlementation and overwrite the serializeGrammars()
      *    and/or deserializeGrammars() to decouple grammars and string pool, or
      *    Once deserializeGrammars() is done, insert another StringPool through
      *    setStringPool().
      *
      *    Client application shall be aware of the unpredicatable/undefined consequence 
      *    of this decoupling.
      */

    virtual void     serializeGrammars(BinOutputStream* const); 
    virtual void     deserializeGrammars(BinInputStream* const); 

private:

    virtual void    createXSModel();

    void
    cleanUp();

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

    // -----------------------------------------------------------------------
    //
    // fGrammarRegistry: 
    //
	//    container
    // fStringPool
    //    grammars need a string pool for URI -> int mappings
    // fSynchronizedStringPool
    //      When the grammar pool is locked, provide a string pool
    //      that can be updated in a thread-safe manner.
    // fLocked
    //      whether the pool has been locked
    //
    // -----------------------------------------------------------------------
    RefHashTableOf<Grammar>*            fGrammarRegistry; 
    XMLStringPool*                      fStringPool;
    XMLSynchronizedStringPool*          fSynchronizedStringPool;
    XSModel*                            fXSModel;
    bool                                fLocked;
    bool                                fXSModelIsValid;
};

XERCES_CPP_NAMESPACE_END

#endif
