Class AbstractFunctionValueSourceWrapper

  • All Implemented Interfaces:
    ValueSource

    public abstract class AbstractFunctionValueSourceWrapper
    extends java.lang.Object
    implements ValueSource
    ValueSource abstract implementation that wraps another value source. When an expression is resolved, this wrapped source is first used to retrieve the expression's actual value; then, the last expression processed by this source is retrieved, and the two are passed into the abstract method executeFunction(String, Object) together. The result of this is returned as the resolved value for the second expression.

    This allows the first expression to be a function name that modifies the value of the second expression, which is resolved from the wrapped value source.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected AbstractFunctionValueSourceWrapper​(ValueSource valueSource)
      Construct a new function value source instance, using the supplied ValueSource to retrieve the input values for the function(s) this class implements.
    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      protected abstract java.lang.Object executeFunction​(java.lang.String expression, java.lang.Object value)
      Execute the function referenced in the last-processed expression using the value resolved from the current expression (using the embedded ValueSource).
      java.lang.Object getValue​(java.lang.String expression)
      Resolve the current expression using the embedded ValueSource Retrieve the last expression processed by this value source Pass the last expression (which should be the function name), along with the value for the current expression, into the executeFunction(..) method Return the result of the executeFunction(..) as the resolved value for the current expression.
      protected ValueSource getValueSource()
      Retrieve the embedded value source.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

    • Constructor Detail

      • AbstractFunctionValueSourceWrapper

        protected AbstractFunctionValueSourceWrapper​(ValueSource valueSource)
        Construct a new function value source instance, using the supplied ValueSource to retrieve the input values for the function(s) this class implements.
        Parameters:
        valueSource - The value source to wrap
    • Method Detail

      • getValue

        public java.lang.Object getValue​(java.lang.String expression)
        1. Resolve the current expression using the embedded ValueSource
        2. Retrieve the last expression processed by this value source
        3. Pass the last expression (which should be the function name), along with the value for the current expression, into the executeFunction(..) method
        4. Return the result of the executeFunction(..) as the resolved value for the current expression.
        Specified by:
        getValue in interface ValueSource
        Parameters:
        expression - The string expression.
        Returns:
        the value related to the expression, or null if not found.
      • getValueSource

        protected ValueSource getValueSource()
        Retrieve the embedded value source.
        Returns:
        ValueSource
      • executeFunction

        protected abstract java.lang.Object executeFunction​(java.lang.String expression,
                                                            java.lang.Object value)
        Execute the function referenced in the last-processed expression using the value resolved from the current expression (using the embedded ValueSource).
        Parameters:
        expression - The last expression to be processed by this value source.
        value - The value for the current expression, resolved by the embedded ValueSource
        Returns:
        The result of modifying the current expression's value using the function named by the last expression.