Package org.geotools.filter

Class LiteralExpressionImpl

Object
ExpressionAbstract
DefaultExpression
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 Details

    • 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 Details

    • 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);