001 /*
002 * GeoAPI - Java interfaces for OGC/ISO standards
003 * http://www.geoapi.org
004 *
005 * Copyright (C) 2006-2012 Open Geospatial Consortium, Inc.
006 * All Rights Reserved. http://www.opengeospatial.org/ogc/legal
007 *
008 * Permission to use, copy, and modify this software and its documentation, with
009 * or without modification, for any purpose and without fee or royalty is hereby
010 * granted, provided that you include the following on ALL copies of the software
011 * and documentation or portions thereof, including modifications, that you make:
012 *
013 * 1. The full text of this NOTICE in a location viewable to users of the
014 * redistributed or derivative work.
015 * 2. Notice of any changes or modifications to the OGC files, including the
016 * date changes were made.
017 *
018 * THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE
019 * NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
020 * TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
021 * THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
022 * PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
023 *
024 * COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR
025 * CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION.
026 *
027 * The name and trademarks of copyright holders may NOT be used in advertising or
028 * publicity pertaining to the software without specific, written prior permission.
029 * Title to copyright in this software and any associated documentation will at all
030 * times remain with copyright holders.
031 */
032 package org.opengis.filter.expression;
033
034 import java.util.List;
035
036 import org.opengis.annotation.XmlElement;
037
038
039 /**
040 * Instances of this class represent a function call into some implementation-specific
041 * function.
042 * <p>
043 * Each execution environment should provide a list of supported functions
044 * (and the number of arguments they expect) as part of a FilterCapabilities
045 * data structure.
046 * <p>
047 * This is included for completeness with respect to the
048 * OGC Filter specification. However, no functions are required to be supported
049 * by that specification.
050 *
051 * @version <A HREF="http://www.opengis.org/docs/02-059.pdf">Implementation specification 1.0</A>
052 * @version <A HREF="http://www.opengeospatial.org/standards/symbol">Symbology Encoding Implementation Specification 1.1.0</A>
053 * @author Chris Dillard (SYS Technologies)
054 * @since GeoAPI 2.0
055 */
056 @XmlElement("Function")
057 public interface Function extends Expression {
058 /**
059 * Returns the name of the function to be called. For example, this might
060 * be "{@code cos}" or "{@code atan2}".
061 * <p>
062 * You can use this name to look up the number of required parameters
063 * in a FilterCapabilities data structure. For the specific meaning of
064 * the required parameters you will need to consult the documentation.
065 */
066 String getName();
067
068 /**
069 * Returns the list subexpressions that will be evaluated to provide the
070 * parameters to the function.
071 */
072 List<Expression> getParameters();
073
074 /**
075 * The value of the fallbackValue attribute is used as a default value, if the SE
076 * implementation does not support the function. If the implementation supports the
077 * function, then the result value is determined by executing the function.
078 *
079 * @return Optional literal to use if an implementation for this function is not available.
080 *
081 * @since GeoAPI 2.2
082 */
083 @XmlElement("fallbackValue")
084 Literal getFallbackValue();
085 }