/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.filter;
/**
* An interface for classes that want to perform operations on a Filter
* hierarchy. It forms part of a GoF Visitor Patern implementation. A call to
* filter.accept(FilterVisitor) will result in a call to one of the methods in
* this interface. The responsibility for traversing sub filters is intended
* to lie with the visitor (this is unusual, but permited under the Visitor
* pattern). A typical use would be to transcribe a filter into a specific
* format, e.g. XML or SQL. Alternativly it may be to extract specific
* infomration from the Filter strucure, for example a list of all bboxes.
*
* @author James Macgill
*
* @source $URL$
* @version $Id$
*
* @task REVISIT: These need to throw some sort of checked exception as the
* implementing classes are swallowing exceptions or throwing runtime
* ones.
*
* @deprecated use {@link org.opengis.filter.FilterVisitor}
*/
public interface FilterVisitor {
/**
* Called when accept is called on an AbstractFilter. As it is imposible to
* create an instance of AbstractFilter this should never happen. If it
* does it means that a subclass of AbstractFilter has failed to implement
* accept(FilterVisitor) correctly. Implementers of this method should
* probaly log a warning.
*
* @param filter The filter to visit
*/
void visit(Filter filter);
/**
* Called when accept is called on a BetweenFilter. Implementers will want
* to access the left, middle and right expresions.
*
* @param filter The filter to visit
*/
void visit(BetweenFilter filter);
/**
* Called when accept is called on a Compare Filter. Implementers will want
* to access the left and right expresions.
*
* @param filter The filter to visit
*/
void visit(CompareFilter filter);
/**
* Called when accept is called on a Geometry Filter. Implementers will
* want to access the left and right geometries.
*
* @param filter The filter to visit
*/
void visit(GeometryFilter filter);
/**
* Called when accept is called on a Like Filter. Implementers will want to
* access the pattern and value.
*
* @param filter The filter to visit.
*/
void visit(LikeFilter filter);
/**
* Called when accept is called on a Logic Filter. Implementers will want
* to access the sub filters.
*
* @param filter The filter to visit.
*/
void visit(LogicFilter filter);
/**
* Called when accept is called on a Null Filter. Implementers will want to
* access the null check.
*
* @param filter The filter to visit.
*/
void visit(NullFilter filter);
/**
* Called when accept is called on a Fid Filter. Implementers will want to
* access the fids.
*
* @param filter The filter to visit.
*/
void visit(FidFilter filter);
/**
* Called when accept is called on an attribute expression. Implementors
* will want to access the attribute.
*
* @param expression The expression to visit.
*/
void visit(AttributeExpression expression);
/**
* This should never be called. This can only happen if a subclass of
* DefaultExpression fails to implement its own version of
* accept(FilterVisitor);
*
* @param expression the expression to visit.
*/
void visit(Expression expression);
/**
* Called when accept is called on a literal expression. Implementors will
* want to access the literal.
*
* @param expression The expression to visit.
*/
void visit(LiteralExpression expression);
/**
* Called when accept is called on an math expression.
*
* @param expression The expression to visit.
*/
void visit(MathExpression expression);
/**
* Called when accept is called on an function expression.
*
* @param expression The expression to visit.
*/
void visit(FunctionExpression expression);
}