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       1             : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
       2             : /*
       3             :  * This file is part of the LibreOffice project.
       4             :  *
       5             :  * This Source Code Form is subject to the terms of the Mozilla Public
       6             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       7             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
       8             :  *
       9             :  * This file incorporates work covered by the following license notice:
      10             :  *
      11             :  *   Licensed to the Apache Software Foundation (ASF) under one or more
      12             :  *   contributor license agreements. See the NOTICE file distributed
      13             :  *   with this work for additional information regarding copyright
      14             :  *   ownership. The ASF licenses this file to you under the Apache
      15             :  *   License, Version 2.0 (the "License"); you may not use this file
      16             :  *   except in compliance with the License. You may obtain a copy of
      17             :  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
      18             :  */
      19             : 
      20             : #ifndef INCLUDED_FORMS_SOURCE_XFORMS_COMPUTEDEXPRESSION_HXX
      21             : #define INCLUDED_FORMS_SOURCE_XFORMS_COMPUTEDEXPRESSION_HXX
      22             : 
      23             : #include <rtl/ustring.hxx>
      24             : #include <com/sun/star/uno/Reference.hxx>
      25             : 
      26             : // forward declaractions
      27             : namespace com { namespace sun { namespace star
      28             : {
      29             :     namespace xml
      30             :     {
      31             :         namespace dom { class XNode; }
      32             :         namespace dom { class XNodeset; }
      33             :         namespace xpath { class XXPathAPI; }
      34             :         namespace xpath { class XXPathObject; }
      35             :     }
      36             :     namespace container { class XNameContainer; }
      37             : } } }
      38             : namespace xforms { class EvaluationContext; }
      39             : 
      40             : 
      41             : 
      42             : namespace xforms
      43             : {
      44             : 
      45             : /** ComputedExpression represents an XPath Expression and caches results.
      46             :  *
      47             :  * As this class has no virtual methods, it should never be used
      48             :  * polymorphically. */
      49             : class ComputedExpression
      50             : {
      51             :     /// the expression string
      52             :     OUString msExpression;
      53             : 
      54             :     /// is msExpression empty?
      55             :     bool mbIsEmpty;
      56             : 
      57             : protected:
      58             :     /// is msExpression a simple expression?
      59             :     bool mbIsSimple;
      60             : 
      61             :     /// the result from the last bind
      62             :     com::sun::star::uno::Reference<com::sun::star::xml::xpath::XXPathObject> mxResult;
      63             : 
      64             : 
      65             :     /// implementation of isSimpleExpression
      66             :     bool _checkExpression( const sal_Char* pExpression ) const;
      67             : 
      68             :     /// allow manipulation of the expression before it is evaluated
      69             :     // the default implementation is to do nothing...
      70           0 :     const OUString _getExpressionForEvaluation() const { return msExpression; }
      71             : 
      72             :     /// obtain a (suitable) XPathAPI implementation
      73             :     static com::sun::star::uno::Reference<com::sun::star::xml::xpath::XXPathAPI> _getXPathAPI(const xforms::EvaluationContext& aContext);
      74             : 
      75             :     /// evaluate the expression relative to the content node.
      76             :     bool _evaluate( const xforms::EvaluationContext& rContext,
      77             :                     const OUString& sExpression );
      78             : 
      79             : 
      80             : public:
      81             :     ComputedExpression();
      82             :     ~ComputedExpression();
      83             : 
      84             : 
      85             :     /// get the expression string
      86           0 :     OUString getExpression() const { return msExpression;}
      87             : 
      88             :     /// set a new expression string
      89             :     void setExpression( const OUString& rExpression );
      90             : 
      91             :     /// get the namespaces that are used to interpret the expression string
      92             :     com::sun::star::uno::Reference<com::sun::star::container::XNameContainer> getNamespaces() const;
      93             : 
      94             :     /// set the namespaces that are used to interpret the expression string
      95             :     void setNamespaces( const com::sun::star::uno::Reference<com::sun::star::container::XNameContainer>& );
      96             : 
      97             :     /// do we have an actual expression?
      98           0 :     bool isEmptyExpression() const { return mbIsEmpty;}
      99             : 
     100             :     /// heuristically determine whether this expression is 'simple',
     101             :     /// i.e. whether its value will change depending on the values
     102             :     /// of other nodes
     103             :     bool isSimpleExpression() const;
     104             : 
     105             : 
     106             :     /// evaluate the expression relative to the content node.
     107             :     bool evaluate( const xforms::EvaluationContext& rContext );
     108             : 
     109             : 
     110             :     /// does this expression have a value?
     111             :     bool hasValue() const;
     112             : 
     113             : 
     114             :     /// remove value/evaluate results
     115             :     void clear();
     116             : 
     117             : 
     118             :     // get the result of this expression as string/bool/...
     119             :     // (Results will be based on the last call of evaluate(..). The caller
     120             :     // must call evaluate to ensure current results.)
     121           0 :     com::sun::star::uno::Reference<com::sun::star::xml::xpath::XXPathObject> getXPath() const { return mxResult;}
     122             :     bool getBool( bool bDefault = false ) const;
     123             :     OUString getString( const OUString& rDefault = OUString() ) const;
     124             : 
     125             : };
     126             : 
     127             : } // namespace xforms
     128             : 
     129             : #endif
     130             : 
     131             : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */