Class NullFilterImpl

All Implemented Interfaces:
Filter, PropertyIsNull, FilterType

public class NullFilterImpl extends AbstractFilter implements PropertyIsNull
Defines a null filter, which checks to see if an attribute is null.
Author:
Rob Hranac, Vision for New York
  • Constructor Details

    • NullFilterImpl

      protected NullFilterImpl(Expression expresion)
  • Method Details

    • getExpression

      public Expression getExpression()
      Returns the expression which represents the null check.
      Specified by:
      getExpression in interface PropertyIsNull
    • setExpression

      public void setExpression(Expression nullCheck)
      Sets the expression which represents the null check.
    • evaluate

      public boolean evaluate(Object feature)
      Determines whether or not a given feature is 'inside' this filter.
      Specified by:
      evaluate in interface Filter
      Parameters:
      feature - Specified feature to examine.
      Returns:
      Flag confirming whether or not this feature is inside the filter.
    • toString

      public String toString()
      Returns a string representation of this filter.
      Overrides:
      toString in class Object
      Returns:
      String representation of the null filter.
    • equals

      public boolean equals(Object o)
      Compares this filter to the specified object. Returns true if the passed in object is the same as this filter. Checks to make sure the filter types, and the NullCheckValue are the same.
      Overrides:
      equals in class Object
      Parameters:
      o - - the object to compare this LikeFilter against.
      Returns:
      true if specified object is equal to this filter; false otherwise.
    • hashCode

      public int hashCode()
      Override of hashCode method.
      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this geometry filter.
    • accept

      public Object accept(FilterVisitor 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 Filter
      Parameters:
      visitor - The visitor which requires access to this filter, the method must call visitor.visit(this);