1 | /*
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2 | * GeoTools - The Open Source Java GIS Toolkit
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3 | * http://geotools.org
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4 | *
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5 | * (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
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6 | *
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7 | * This library is free software; you can redistribute it and/or
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8 | * modify it under the terms of the GNU Lesser General Public
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9 | * License as published by the Free Software Foundation;
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10 | * version 2.1 of the License.
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11 | *
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12 | * This library is distributed in the hope that it will be useful,
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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15 | * Lesser General Public License for more details.
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16 | */
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17 | package org.geotools.filter;
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18 |
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19 | import java.util.ArrayList;
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20 | import java.util.Collections;
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21 | import java.util.List;
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22 |
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23 | import org.geotools.filter.expression.ExpressionAbstract;
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24 | import org.opengis.filter.expression.Expression;
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25 | import org.opengis.filter.expression.ExpressionVisitor;
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26 | import org.opengis.filter.expression.Function;
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27 | import org.opengis.filter.expression.Literal;
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28 |
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29 | /**
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30 | * Default implementation of a Function; you may extend this class to
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31 | * implement specific functionality.
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32 | * <p>
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33 | *
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34 | * @author Cory Horner, Refractions Research
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35 | *
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36 | *
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37 | *
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38 | * @source $URL: http://svn.osgeo.org/geotools/branches/2.7.x/modules/library/main/src/main/java/org/geotools/filter/FunctionImpl.java $
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39 | */
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40 | public class FunctionImpl extends ExpressionAbstract implements Function {
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41 |
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42 | /** function name **/
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43 | String name;
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44 |
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45 | /** function params **/
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46 | List<Expression> params = Collections.emptyList();
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47 |
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48 | Literal fallbackValue;
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49 |
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50 | /**
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51 | * Gets the name of this function.
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52 | *
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53 | * @return the name of the function.
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54 | *
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55 | */
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56 | public String getName() {
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57 | return name;
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58 | }
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59 |
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60 | /**
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61 | * Returns the function parameters.
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62 | */
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63 | public List<Expression> getParameters() {
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64 | return new ArrayList<Expression>(params);
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65 | }
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66 |
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67 | /**
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68 | * Default implementation simply returns the fallbackValue.
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69 | * <p>
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70 | * Please override this method to produce a value based on the
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71 | * provided arguments.
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72 | * @param object Object being evaluated; often a Feature
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73 | * @return value for the provided object
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74 | */
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75 | public Object evaluate(Object object) {
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76 | return fallbackValue.evaluate( object );
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77 | }
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78 |
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79 | /**
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80 | * Sets the function parameters.
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81 | */
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82 | @SuppressWarnings("unchecked")
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83 | public void setParameters(List<Expression> params) {
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84 | this.params = params == null? Collections.EMPTY_LIST : new ArrayList<Expression>(params);
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85 | }
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86 |
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87 | public void setFallbackValue(Literal fallbackValue) {
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88 | this.fallbackValue = fallbackValue;
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89 | }
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90 |
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91 | public Object accept(ExpressionVisitor visitor, Object extraData) {
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92 | return visitor.visit( this, extraData );
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93 | }
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94 | }
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