00001 /*
00002  * Copyright 2006-2008 The FLWOR Foundation.
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  * 
00008  * http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #ifndef ZORBA_ITERATOR_API_H
00017 #define ZORBA_ITERATOR_API_H
00018 
00019 #include <zorba/config.h>
00020 #include <zorba/api_shared_types.h>
00021 #include <zorba/item_sequence.h>
00022 
00023 namespace zorba {
00024 
00025   /** \brief Interface for an Iterator over an instance of the XML Data Model.
00026     *
00027     * Note: This class is reference counted. When writing multi-threaded clients,
00028     * it is the responibility of the client code to synchronize assignments to the
00029     * SmartPtr holding this object.
00030     */
00031   class ZORBA_EXTERN_DECL Iterator : public ItemSequence, public SmartObject
00032   {
00033     public:
00034       /** \brief Destructor
00035        */
00036       virtual ~Iterator() {}
00037 
00038       /** \brief Start iterating
00039        *
00040        * This function needs to be called before calling next.
00041        * @throw ZorbaException if an error occurs.
00042        */
00043       virtual void 
00044       open() = 0;
00045 
00046       /** \brief Get the next Item of the sequence.
00047        * @param aItem the next Item of the result sequence if true is returned by the function.
00048        * @return true if the sequence is not exhausted, false otherwise.
00049        * @throw ZorbaException if an error occurs during query execution or the Iterator has
00050        *        not been opened.
00051        */
00052       virtual bool
00053       next(Item& aItem) = 0;
00054 
00055       /** \brief Stop iterating.
00056        *
00057        * In order to call Iterator::next, open has to been called.
00058        */
00059       virtual void 
00060       close() = 0;
00061 
00062   };
00063 
00064 } /* namespace zorba */
00065 #endif
Zorba

iterator.h
