Package org.jfree.report.expressions

Interface Expression

    • Method Summary

      All Methods Instance Methods Abstract Methods 
      Modifier and Type Method Description
      java.lang.Object clone()
      Clones the expression, expression should be reinitialized after the cloning.
      java.lang.Object computeValue()
      Return the current expression value.
      Expression getInstance()
      Return a new instance of this expression.
      java.lang.String getName()
      Returns the name of the expression.
      boolean isDeepTraversing()
      A deep-traversing expression declares that it should receive updates from all subreports.
      boolean isPrecompute()
      Returns, whether the expression will be precomputed.
      boolean isPreserve()
      Checks, whether the expression's result should be preserved in the precomputed value registry.
      void setDeepTraversing​(boolean deepTraversing)
      Defines, whether the expression is deep-traversing.
      void setName​(java.lang.String name)
      Sets the name of the expression.
      void setPrecompute​(boolean precompute)
      Defines, whether the expression will be precomputed.
      void setPreserve​(boolean preserve)
      Defines, whether the expression's result should be preserved in the precomputed value registry.
      void setRuntime​(ExpressionRuntime runtime)
      Defines the DataRow used in this expression.

    • Method Detail

      • getName

        java.lang.String getName()
        Returns the name of the expression. An expression without a name cannot be referenced from outside the element.
        Returns:
        the function name.

      • setName

        void setName​(java.lang.String name)
        Sets the name of the expression.
        Parameters:
        name - the name.

      • computeValue

        java.lang.Object computeValue()
                       throws DataSourceException
        Return the current expression value.

        The value depends (obviously) on the expression implementation.

        Returns:
        the value of the function.
        Throws:
        DataSourceException

      • clone

        java.lang.Object clone()
                throws java.lang.CloneNotSupportedException
        Clones the expression, expression should be reinitialized after the cloning.

        Expression maintain no state, cloning is done at the beginning of the report processing to disconnect the used expression from any other object space.

        Returns:
        A clone of this expression.
        Throws:
        java.lang.CloneNotSupportedException - this should never happen.

      • getInstance

        Expression getInstance()
        Return a new instance of this expression. The copy is initialized and uses the same parameters as the original, but does not share any objects.
        Returns:
        a copy of this function.

      • setRuntime

        void setRuntime​(ExpressionRuntime runtime)
        Defines the DataRow used in this expression. The dataRow is set when the report processing starts and can be used to access the values of functions, expressions and the reports datasource.
        Parameters:
        runtime - the runtime information for the expression

      • isDeepTraversing

        boolean isDeepTraversing()
        A deep-traversing expression declares that it should receive updates from all subreports. This mode should be activated if the expression's result depends on values contained in the subreport.
        Returns:
        true, if the expression is deep-traversing, false otherwise.

      • setDeepTraversing

        void setDeepTraversing​(boolean deepTraversing)
        Defines, whether the expression is deep-traversing.
        Parameters:
        deepTraversing - true, if the expression is deep-traversing, false otherwise.

      • isPrecompute

        boolean isPrecompute()
        Returns, whether the expression will be precomputed. For precomputed expressions a parallel evaluation process is started and the result to which the expression evaluates before it gets out of scope will be used whenever an other expression queries this expression's value.
        Returns:
        true, if the expression is precomputed, false otherwise.

      • setPrecompute

        void setPrecompute​(boolean precompute)
        Defines, whether the expression will be precomputed. For precomputed expressions a parallel evaluation process is started and the result to which the expression evaluates before it gets out of scope will be used whenever an other expression queries this expression's value.
        Parameters:
        precompute - true, if the expression is precomputed, false otherwise.

      • isPreserve

        boolean isPreserve()
        Checks, whether the expression's result should be preserved in the precomputed value registry. This way, the last value for that expression can be retrieved after the report has been finished. The preserve-function will only preserve the last value that has been evaluated before the expression went out of scope.
        Returns:
        true, if the expression's results should be preserved, false otherwise.

      • setPreserve

        void setPreserve​(boolean preserve)
        Defines, whether the expression's result should be preserved in the precomputed value registry. This way, the last value for that expression can be retrieved after the report has been finished.
        Parameters:
        preserve - true, if the expression's results should be preserved, false otherwise.