1 /* 2 * Copyright (c) 2002, 2008, 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 package javax.swing.plaf.synth; 26 27 import java.util.Queue; 28 import java.util.concurrent.ConcurrentLinkedQueue; 29 import javax.swing.JComponent; 30 31 /** 32 * An immutable transient object containing contextual information about 33 * a <code>Region</code>. A <code>SynthContext</code> should only be 34 * considered valid for the duration 35 * of the method it is passed to. In other words you should not cache 36 * a <code>SynthContext</code> that is passed to you and expect it to 37 * remain valid. 38 * 39 * @since 1.5 40 * @author Scott Violet 41 */ 42 public class SynthContext { 43 private static final Queue<SynthContext> queue = new ConcurrentLinkedQueue<>(); 44 45 private JComponent component; 46 private Region region; 47 private SynthStyle style; 48 private int state; 49 50 static SynthContext getContext(JComponent c, SynthStyle style, int state) { 51 return getContext(c, SynthLookAndFeel.getRegion(c), style, state); 52 } 53 54 static SynthContext getContext(JComponent component, 55 Region region, SynthStyle style, 56 int state) { 57 SynthContext context = queue.poll(); 58 if (context == null) { 59 context = new SynthContext(); 60 } 61 context.reset(component, region, style, state); 62 return context; 63 } 64 65 static void releaseContext(SynthContext context) { 66 queue.offer(context); 67 } 68 69 SynthContext() { 70 } 71 72 /** 73 * Creates a SynthContext with the specified values. This is meant 74 * for subclasses and custom UI implementors. You very rarely need to 75 * construct a SynthContext, though some methods will take one. 76 * 77 * @param component JComponent 78 * @param region Identifies the portion of the JComponent 79 * @param style Style associated with the component 80 * @param state State of the component as defined in SynthConstants. 81 * @throws NullPointerException if component, region of style is null. 82 */ 83 public SynthContext(JComponent component, Region region, SynthStyle style, 84 int state) { 85 if (component == null || region == null || style == null) { 86 throw new NullPointerException( 87 "You must supply a non-null component, region and style"); 88 } 89 reset(component, region, style, state); 90 } 91 92 93 /** 94 * Returns the hosting component containing the region. 95 * 96 * @return Hosting Component 97 */ 98 public JComponent getComponent() { 99 return component; 100 } 101 102 /** 103 * Returns the Region identifying this state. 104 * 105 * @return Region of the hosting component 106 */ 107 public Region getRegion() { 108 return region; 109 } 110 111 /** 112 * A convenience method for <code>getRegion().isSubregion()</code>. 113 */ 114 boolean isSubregion() { 115 return getRegion().isSubregion(); 116 } 117 118 void setStyle(SynthStyle style) { 119 this.style = style; 120 } 121 122 /** 123 * Returns the style associated with this Region. 124 * 125 * @return SynthStyle associated with the region. 126 */ 127 public SynthStyle getStyle() { 128 return style; 129 } 130 131 void setComponentState(int state) { 132 this.state = state; 133 } 134 135 /** 136 * Returns the state of the widget, which is a bitmask of the 137 * values defined in <code>SynthConstants</code>. A region will at least 138 * be in one of 139 * <code>ENABLED</code>, <code>MOUSE_OVER</code>, <code>PRESSED</code> 140 * or <code>DISABLED</code>. 141 * 142 * @see SynthConstants 143 * @return State of Component 144 */ 145 public int getComponentState() { 146 return state; 147 } 148 149 /** 150 * Resets the state of the Context. 151 */ 152 void reset(JComponent component, Region region, SynthStyle style, 153 int state) { 154 this.component = component; 155 this.region = region; 156 this.style = style; 157 this.state = state; 158 } 159 160 void dispose() { 161 this.component = null; 162 this.style = null; 163 releaseContext(this); 164 } 165 166 /** 167 * Convenience method to get the Painter from the current SynthStyle. 168 * This will NEVER return null. 169 */ 170 SynthPainter getPainter() { 171 SynthPainter painter = getStyle().getPainter(this); 172 173 if (painter != null) { 174 return painter; 175 } 176 return SynthPainter.NULL_PAINTER; 177 } 178 }