forms/source/xforms/computedexpression.hxx

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  19
  20 #ifndef _COMPUTEDEXPRESSION_HXX
  21 #define _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     const OUString _getExpressionForEvaluation() const;
  70
  71     /// obtain a (suitable) XPathAPI implementation
  72     com::sun::star::uno::Reference<com::sun::star::xml::xpath::XXPathAPI> _getXPathAPI(const xforms::EvaluationContext& aContext);
  73
  74     /// evaluate the expression relative to the content node.
  75     bool _evaluate( const xforms::EvaluationContext& rContext,
  76                     const OUString& sExpression );
  77
  78
  79 public:
  80     ComputedExpression();
  81     ~ComputedExpression();
  82
  83
  84     /// get the expression string
  85     OUString getExpression() const;
  86
  87     /// set a new expression string
  88     void setExpression( const OUString& rExpression );
  89
  90     /// get the namespaces that are used to interpret the expression string
  91     com::sun::star::uno::Reference<com::sun::star::container::XNameContainer> getNamespaces() const;
  92
  93     /// set the namespaces that are used to interpret the expression string
  94     void setNamespaces( const com::sun::star::uno::Reference<com::sun::star::container::XNameContainer>& );
  95
  96     /// do we have an actual expression?
  97     bool isEmptyExpression() const;
  98
  99     /// heuristically determine whether this expression is 'simple',
 100     /// i.e. whether its value will change depending on the values
 101     /// of other nodes
 102     bool isSimpleExpression() const;
 103
 104
 105     /// evaluate the expression relative to the content node.
 106     bool evaluate( const xforms::EvaluationContext& rContext );
 107
 108
 109     /// does this expression have a value?
 110     bool hasValue() const;
 111
 112
 113     /// remove value/evaluate results
 114     void clear();
 115
 116
 117     // get the result of this expression as string/bool/...
 118     // (Results will be based on the last call of evaluate(..). The caller
 119     // must call evaluate to ensure current results.)
 120     com::sun::star::uno::Reference<com::sun::star::xml::xpath::XXPathObject> getXPath() const;
 121     bool getBool( bool bDefault = false ) const;
 122     OUString getString( const OUString& rDefault = OUString() ) const;
 123
 124 };
 125
 126 } // namespace xforms
 127
 128 #endif
 129
 130 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */