Package org.geotools.filter

Class LiteralExpressionImpl

  • All Implemented Interfaces:
    Expression, Literal
    public class LiteralExpressionImpl
extends DefaultExpression
implements Literal
    Defines an expression that holds a literal for return.
    Author:
    Rob Hranac, Vision for New York

    • Constructor Detail

      • LiteralExpressionImpl

        protected LiteralExpressionImpl()
        Constructor with literal.

      • LiteralExpressionImpl

        public LiteralExpressionImpl​(Object literal)
                      throws IllegalFilterException
        Constructor with literal.
        Parameters:
        literal - The literal to store inside this expression.
        Throws:
        IllegalFilterException - This literal type is not in scope.

      • LiteralExpressionImpl

        protected LiteralExpressionImpl​(int value)
        Constructor with literal. This alternative constructor is a convinience one for integers an Integer object will be constructed, and no IllegalFilterException can ever be thrown.
        Parameters:
        value - The integer to store inside this expression.

      • LiteralExpressionImpl

        protected LiteralExpressionImpl​(long value)

      • LiteralExpressionImpl

        protected LiteralExpressionImpl​(double value)
        Constructor with literal. This alternative constructor is a convinience one for doubles an Double object will be constructed, and no IllegalFilterException can ever be thrown.
        Parameters:
        value - The double to store inside this expression.

      • LiteralExpressionImpl

        protected LiteralExpressionImpl​(String value)
        Constructor with literal. This alternative constructor is a convinience one for doubles an Double object will be constructed, and no IllegalFilterException can ever be thrown.
        Parameters:
        value - The double to store inside this expression.

    • Method Detail

      • getValue

        public Object getValue()
        Retrieves the literal of this expression.
        Specified by:
        getValue in interface Literal
        Returns:
        the literal held by this expression.

      • setValue

        public final void setValue​(Object literal)
        Sets the literal.
        Parameters:
        literal - The literal to store inside this expression.
        Throws:
        IllegalFilterException - This literal type is not in scope.

      • evaluate

        public Object evaluate​(Object feature)
        Description copied from class: ExpressionAbstract
        Subclass should override, default implementation returns null.
        Specified by:
        evaluate in interface Expression
        Overrides:
        evaluate in class ExpressionAbstract
        Returns:
        default implementation returns null

      • evaluate

        public <T> T evaluate​(Object feature,
                      Class<T> context)
        Description copied from class: ExpressionAbstract
        Default implementation delegates handling of context conversion to Converters utility class.

        Subclasses are expected to make use of the Converters utility class (as the easiest way to provide value morphing in conformance with the Filter specification).

        Specified by:
        evaluate in interface Expression
        Overrides:
        evaluate in class ExpressionAbstract
        Type Parameters:
        T - The type of the returned object.
        Parameters:
        feature - The object to evaluate the expression against.
        context - The type of the resulting value of the expression.
        Returns:
        Evaluates the given expression based on the content of the given object an an instance of context.

      • toString

        public String toString()
        Return this filter as a string.
        Overrides:
        toString in class Object
        Returns:
        String representation of this geometry filter.

      • equals

        public boolean equals​(Object obj)
        Compares this filter to the specified object. Returns true if the passed in object is the same as this expression. Checks to make sure the expression types are the same as well as the literals.
        Overrides:
        equals in class Object
        Parameters:
        obj - - the object to compare this ExpressionLiteral against.
        Returns:
        true if specified object is equal to this expression; false otherwise.
        TODO:
        REVISIT: missmatched types now considered not equal. This may be a problem when comparing Doubles and Integers

      • hashCode

        public int hashCode()
        Override of hashCode method.
        Overrides:
        hashCode in class Object
        Returns:
        the hash code for this literal expression

      • accept

        public Object accept​(ExpressionVisitor visitor,
                     Object extraData)
        Used by FilterVisitors to perform some action on this filter instance. Typicaly used by Filter decoders, but may also be used by any thing which needs infomration from filter structure. Implementations should always call: visitor.visit(this); It is importatant that this is not left to a parent class unless the parents API is identical.
        Specified by:
        accept in interface Expression
        Parameters:
        visitor - The visitor which requires access to this filter, the method must call visitor.visit(this);