01: /*
02: * GeoTools - OpenSource mapping toolkit
03: * http://geotools.org
04: * (C) 2005-2006, GeoTools Project Managment Committee (PMC)
05: *
06: * This library is free software; you can redistribute it and/or
07: * modify it under the terms of the GNU Lesser General Public
08: * License as published by the Free Software Foundation;
09: * version 2.1 of the License.
10: *
11: * This library is distributed in the hope that it will be useful,
12: * but WITHOUT ANY WARRANTY; without even the implied warranty of
13: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14: * Lesser General Public License for more details.
15: */
16: package org.geotools.filter;
17:
18: import org.geotools.feature.Feature;
19:
20: /**
21: * Defines a complex filter (could also be called logical filter). This filter
22: * holds one or more filters together and relates them logically in an
23: * internally defined manner.
24: *
25: * @author Rob Hranac, TOPP
26: * @source $URL: http://svn.geotools.org/geotools/tags/2.4.1/modules/unsupported/hsql/src/main/java/org/geotools/filter/GeometryExpressionImpl.java $
27: * @version $Id: GeometryExpressionImpl.java 22226 2006-10-18 20:06:40Z acuster $
28: */
29: public class GeometryExpressionImpl extends DefaultExpression {
30:
31: /** Holds all sub filters of this filter. */
32: protected String attPath;
33:
34: /** Holds all sub filters of this filter. */
35: protected String colName = null;
36:
37: /**
38: * Constructor with the schema for this attribute.
39: *
40: * @param colName a String with the schema for this attribute.
41: */
42: protected GeometryExpressionImpl(String colName) {
43: this .colName = colName;
44: this .expressionType = ATTRIBUTE;
45: }
46:
47: /**
48: * Gets the value of this attribute from the passed feature.
49: *
50: * @param feature Feature from which to extract attribute value.
51: */
52: public Object evaluate(Feature feature) {
53: return feature.getAttribute(attPath);
54: }
55:
56: /**
57: * Return this expression as a string.
58: *
59: * @return String representation of this attribute expression.
60: */
61: public String toString() {
62: return attPath;
63: }
64:
65: /**
66: * Used by FilterVisitors to perform some action on this filter instance.
67: * Typicaly used by Filter decoders, but may also be used by any thing
68: * which needs infomration from filter structure. Implementations should
69: * always call: visitor.visit(this); It is importatant that this is not
70: * left to a parent class unless the parents API is identical.
71: *
72: * @param visitor The visitor which requires access to this filter, the
73: * method must call visitor.visit(this);
74: *
75: * @todo This method can't be overriden anymore as of Geotools 2.3. Replaced by
76: * {@link org.opengis.filter.expression.Expression#accept(ExpressionVisitor, Object)}.
77: */
78: // public void accept(FilterVisitor visitor) {
79: // visitor.visit(this);
80: // }
81: }
|