1 /*
2 * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javafx.scene.control.cell;
27
28 import javafx.beans.NamedArg;
29 import javafx.beans.property.Property;
30 import javafx.beans.property.ReadOnlyObjectWrapper;
31 import javafx.beans.value.ObservableValue;
32 import javafx.scene.control.TableCell;
33 import javafx.scene.control.TableColumn;
34 import javafx.scene.control.TableColumn.CellDataFeatures;
35 import javafx.scene.control.TableView;
36 import javafx.util.Callback;
37
38 import com.sun.javafx.logging.PlatformLogger;
39 import com.sun.javafx.logging.PlatformLogger.Level;
40 import com.sun.javafx.property.PropertyReference;
41 import com.sun.javafx.scene.control.Logging;
42
43
44 /**
45 * A convenience implementation of the Callback interface, designed specifically
46 * for use within the {@link TableColumn}
47 * {@link TableColumn#cellValueFactoryProperty() cell value factory}. An example
48 * of how to use this class is:
49 *
50 * <pre><code>
51 * TableColumn<Person,String> firstNameCol = new TableColumn<Person,String>("First Name");
52 * firstNameCol.setCellValueFactory(new PropertyValueFactory<Person,String>("firstName"));
53 * </code></pre>
54 *
55 * <p>
56 * In this example, {@code Person} is the class type of the {@code TableView}
57 * {@link TableView#itemsProperty() items} list.
58 * The class {@code Person} must be declared public.
59 * {@code PropertyValueFactory} uses the constructor argument,
60 * {@code "firstName"}, to assume that {@code Person} has a public method
61 * {@code firstNameProperty} with no formal parameters and a return type of
62 * {@code ObservableValue<String>}.
63 * </p>
64 * <p>
65 * If such a method exists, then it is invoked, and additionally assumed
66 * to return an instance of {@code Property<String>}. The return value is used
67 * to populate the {@link TableCell}. In addition, the {@code TableView} adds
68 * an observer to the return value, such that any changes fired will be observed
69 * by the {@code TableView}, resulting in the cell immediately updating.
70 * </p>
71 * <p>
72 * If no such method exists, then {@code PropertyValueFactory}
73 * assumes that {@code Person} has a public method {@code getFirstName} or
74 * {@code isFirstName} with no formal parameters and a return type of
75 * {@code String}. If such a method exists, then it is invoked, and its return
76 * value is wrapped in a {@link ReadOnlyObjectWrapper}
77 * and returned to the {@code TableCell}. In this situation,
78 * the {@code TableCell} will not be able to observe changes to the property,
79 * unlike in the first approach above.
80 * </p>
81 *
82 * <p>For reference (and as noted in the TableColumn
83 * {@link TableColumn#cellValueFactoryProperty()} cell value factory} documentation), the
84 * long form of the code above would be the following:
85 * </p>
86 *
87 * <pre><code>
88 * TableColumn<Person,String> firstNameCol = new TableColumn<Person,String>("First Name");
89 * firstNameCol.setCellValueFactory(new Callback<CellDataFeatures<Person, String>, ObservableValue<String>>() {
90 * public ObservableValue<String> call(CellDataFeatures<Person, String> p) {
91 * // p.getValue() returns the Person instance for a particular TableView row
92 * return p.getValue().firstNameProperty();
93 * }
94 * });
95 * }
96 * </code></pre>
97 *
98 * <p><b>Deploying an Application as a Module</b></p>
99 * <p>
100 * If the referenced class is in a named module, then it must be reflectively
101 * accessible to the {@code javafx.base} module.
102 * A class is reflectively accessible if the module
103 * {@link Module#isOpen(String,Module) opens} the containing package to at
104 * least the {@code javafx.base} module.
105 * Otherwise the {@link #call call(TableColumn.CellDataFeatures)} method
106 * will log a warning and return {@code null}.
107 * </p>
108 * <p>
109 * For example, if the {@code Person} class is in the {@code com.foo} package
110 * in the {@code foo.app} module, the {@code module-info.java} might
111 * look like this:
112 * </p>
113 *
114 <pre>{@code module foo.app {
115 opens com.foo to javafx.base;
116 }}</pre>
117 *
118 * <p>
119 * Alternatively, a class is reflectively accessible if the module
120 * {@link Module#isExported(String) exports} the containing package
121 * unconditionally.
122 * </p>
123 *
124 * @see TableColumn
125 * @see TableView
126 * @see TableCell
127 * @see TreeItemPropertyValueFactory
128 * @see MapValueFactory
129 * @param <S> The type of the class contained within the TableView.items list.
130 * @param <T> The type of the class contained within the TableColumn cells.
131 * @since JavaFX 2.0
132 */
133 public class PropertyValueFactory<S,T> implements Callback<CellDataFeatures<S,T>, ObservableValue<T>> {
134
135 private final String property;
136
137 private Class<?> columnClass;
138 private String previousProperty;
139 private PropertyReference<T> propertyRef;
140
141 /**
142 * Creates a default PropertyValueFactory to extract the value from a given
143 * TableView row item reflectively, using the given property name.
144 *
145 * @param property The name of the property with which to attempt to
146 * reflectively extract a corresponding value for in a given object.
147 */
148 public PropertyValueFactory(@NamedArg("property") String property) {
149 this.property = property;
150 }
151
152 /** {@inheritDoc} */
153 @Override public ObservableValue<T> call(CellDataFeatures<S,T> param) {
154 return getCellDataReflectively(param.getValue());
155 }
156
157 /**
158 * Returns the property name provided in the constructor.
159 * @return the property name provided in the constructor
160 */
161 public final String getProperty() { return property; }
162
163 private ObservableValue<T> getCellDataReflectively(S rowData) {
164 if (getProperty() == null || getProperty().isEmpty() || rowData == null) return null;
165
166 try {
167 // we attempt to cache the property reference here, as otherwise
168 // performance suffers when working in large data models. For
169 // a bit of reference, refer to RT-13937.
170 if (columnClass == null || previousProperty == null ||
171 ! columnClass.equals(rowData.getClass()) ||
172 ! previousProperty.equals(getProperty())) {
173
174 // create a new PropertyReference
175 this.columnClass = rowData.getClass();
176 this.previousProperty = getProperty();
177 this.propertyRef = new PropertyReference<T>(rowData.getClass(), getProperty());
178 }
179
180 if (propertyRef != null) {
181 if (propertyRef.hasProperty()) {
182 return propertyRef.getProperty(rowData);
183 } else {
184 T value = propertyRef.get(rowData);
185 return new ReadOnlyObjectWrapper<T>(value);
186 }
187 }
188 } catch (RuntimeException e) {
189 // log the warning and move on
190 final PlatformLogger logger = Logging.getControlsLogger();
191 if (logger.isLoggable(Level.WARNING)) {
192 logger.warning("Can not retrieve property '" + getProperty() +
193 "' in PropertyValueFactory: " + this +
194 " with provided class type: " + rowData.getClass(), e);
195 }
196 propertyRef = null;
197 }
198
199 return null;
200 }
201 }