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1: /* =========================================================== 2: * JFreeChart : a free chart library for the Java(tm) platform 3: * =========================================================== 4: * 5: * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jfreechart/index.html 8: * 9: * This library is free software; you can redistribute it and/or modify it 10: * under the terms of the GNU Lesser General Public License as published by 11: * the Free Software Foundation; either version 2.1 of the License, or 12: * (at your option) any later version. 13: * 14: * This library is distributed in the hope that it will be useful, but 15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 17: * License for more details. 18: * 19: * You should have received a copy of the GNU Lesser General Public 20: * License along with this library; if not, write to the Free Software 21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 22: * USA. 23: * 24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 25: * in the United States and other countries.] 26: * 27: * ---------------------- 28: * AbstractDialLayer.java 29: * ---------------------- 30: * (C) Copyright 2006-2007, by Object Refinery Limited. 31: * 32: * Original Author: David Gilbert (for Object Refinery Limited); 33: * Contributor(s): -; 34: * 35: * Changes 36: * ------- 37: * 06-Nov-2006 : Version 1 (DG); 38: * 17-Nov-2006 : Added visible flag (DG); 39: * 16-Oct-2007 : Implemented equals() and clone() (DG); 40: * 41: */ 42: 43: package org.jfree.chart.plot.dial; 44: 45: import java.io.IOException; 46: import java.io.ObjectInputStream; 47: import java.util.Arrays; 48: import java.util.EventListener; 49: import java.util.List; 50: 51: import javax.swing.event.EventListenerList; 52: 53: import org.jfree.chart.HashUtilities; 54: 55: /** 56: * A base class that can be used to implement a {@link DialLayer}. It includes 57: * an event notification mechanism. 58: */ 59: public abstract class AbstractDialLayer implements DialLayer { 60: 61: /** A flag that controls whether or not the layer is visible. */ 62: private boolean visible; 63: 64: /** Storage for registered listeners. */ 65: private transient EventListenerList listenerList; 66: 67: /** 68: * Creates a new instance. 69: */ 70: protected AbstractDialLayer() { 71: this.visible = true; 72: this.listenerList = new EventListenerList(); 73: } 74: 75: /** 76: * Returns <code>true</code> if this layer is visible (should be displayed), 77: * and <code>false</code> otherwise. 78: * 79: * @return A boolean. 80: * 81: * @see #setVisible(boolean) 82: */ 83: public boolean isVisible() { 84: return this.visible; 85: } 86: 87: /** 88: * Sets the flag that determines whether or not this layer is drawn by 89: * the plot, and sends a {@link DialLayerChangeEvent} to all registered 90: * listeners. 91: * 92: * @param visible the flag. 93: * 94: * @see #isVisible() 95: */ 96: public void setVisible(boolean visible) { 97: this.visible = visible; 98: notifyListeners(new DialLayerChangeEvent(this)); 99: } 100: 101: /** 102: * Tests this instance for equality with an arbitrary object. 103: * 104: * @param obj the object (<code>null</code> permitted). 105: * 106: * @return A boolean. 107: */ 108: public boolean equals(Object obj) { 109: if (obj == this) { 110: return true; 111: } 112: if (!(obj instanceof AbstractDialLayer)) { 113: return false; 114: } 115: AbstractDialLayer that = (AbstractDialLayer) obj; 116: return this.visible == that.visible; 117: } 118: 119: /** 120: * Returns a hash code for this instance. 121: * 122: * @return A hash code. 123: */ 124: public int hashCode() { 125: int result = 23; 126: result = HashUtilities.hashCode(result, this.visible); 127: return result; 128: } 129: 130: /** 131: * Returns a clone of this instance. 132: * 133: * @return A clone. 134: * 135: * @throws CloneNotSupportedException if there is a problem cloning this 136: * instance. 137: */ 138: public Object clone() throws CloneNotSupportedException { 139: AbstractDialLayer clone = (AbstractDialLayer) super.clone(); 140: // we don't clone the listeners 141: clone.listenerList = new EventListenerList(); 142: return clone; 143: } 144: 145: /** 146: * Registers an object for notification of changes to the dial layer. 147: * 148: * @param listener the object that is being registered. 149: * 150: * @see #removeChangeListener(DialLayerChangeListener) 151: */ 152: public void addChangeListener(DialLayerChangeListener listener) { 153: this.listenerList.add(DialLayerChangeListener.class, listener); 154: } 155: 156: /** 157: * Deregisters an object for notification of changes to the dial layer. 158: * 159: * @param listener the object to deregister. 160: * 161: * @see #addChangeListener(DialLayerChangeListener) 162: */ 163: public void removeChangeListener(DialLayerChangeListener listener) { 164: this.listenerList.remove(DialLayerChangeListener.class, listener); 165: } 166: 167: /** 168: * Returns <code>true</code> if the specified object is registered with 169: * the dataset as a listener. Most applications won't need to call this 170: * method, it exists mainly for use by unit testing code. 171: * 172: * @param listener the listener. 173: * 174: * @return A boolean. 175: */ 176: public boolean hasListener(EventListener listener) { 177: List list = Arrays.asList(this.listenerList.getListenerList()); 178: return list.contains(listener); 179: } 180: 181: /** 182: * Notifies all registered listeners that the dial layer has changed. 183: * The {@link DialLayerChangeEvent} provides information about the change. 184: * 185: * @param event information about the change to the axis. 186: */ 187: protected void notifyListeners(DialLayerChangeEvent event) { 188: Object[] listeners = this.listenerList.getListenerList(); 189: for (int i = listeners.length - 2; i >= 0; i -= 2) { 190: if (listeners[i] == DialLayerChangeListener.class) { 191: ((DialLayerChangeListener) listeners[i + 1]).dialLayerChanged( 192: event); 193: } 194: } 195: } 196: 197: /** 198: * Provides serialization support. 199: * 200: * @param stream the input stream. 201: */ 202: private void readObject(ObjectInputStream stream) 203: throws IOException, ClassNotFoundException { 204: stream.defaultReadObject(); 205: this.listenerList = new EventListenerList(); 206: } 207: 208: }