forms/source/xforms/computedexpression.hxx

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  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     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     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     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     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: */