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1: /* ComponentOrientation.java -- describes a component's orientation 2: Copyright (C) 2000, 2001, 2002 Free Software Foundation 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package java.awt; 40: 41: import java.io.Serializable; 42: import java.util.Locale; 43: import java.util.MissingResourceException; 44: import java.util.ResourceBundle; 45: 46: /** 47: * This class is used to differentiate different orientations for text layout. 48: * It controls whether text flows left-to-right or right-to-left, and whether 49: * lines are horizontal or vertical, as in this table:<br> 50: * <pre> 51: * LT RT TL TR 52: * A B C C B A A D G G D A 53: * D E F F E D B E H H E B 54: * G H I I H G C F I I F C 55: * </pre> 56: * <b>LT</b> languages are most common (left-to-right lines, top-to-bottom). 57: * This includes Western European languages, and optionally includes Japanese, 58: * Chinese, and Korean. <b>RT</b> languages (right-to-left lines, 59: * top-to-bottom) are mainly middle eastern, such as Hebrew and Arabic. 60: * <b>TR</b> languages flow top-to-bottom in a line, right-to-left, and are 61: * the basis of Japanese, Chinese, and Korean. Finally, <b>TL</b> languages 62: * flow top-to-bottom in a line, left-to-right, as in Mongolian. 63: * 64: * <p>This is a pretty poor excuse for a type-safe enum, since it is not 65: * guaranteed that orientation objects are unique (thanks to serialization), 66: * yet there is no equals() method. You would be wise to compare the output 67: * of isHorizontal() and isLeftToRight() rather than comparing objects with 68: * ==, especially since more constants may be added in the future. 69: * 70: * @author Bryce McKinlay (bryce@albatross.co.nz) 71: * @since 1.0 72: * @status updated to 1.4 73: */ 74: public final class ComponentOrientation implements Serializable 75: { 76: /** 77: * Compatible with JDK 1.0+. 78: */ 79: private static final long serialVersionUID = -4113291392143563828L; 80: 81: /** Constant for unknown orientation. */ 82: private static final int UNKNOWN_ID = 1; 83: 84: /** Constant for horizontal line orientation. */ 85: private static final int HORIZONTAL_ID = 2; 86: 87: /** Constant for left-to-right orientation. */ 88: private static final int LEFT_TO_RIGHT_ID = 4; 89: 90: /** 91: * Items run left to right, and lines flow top to bottom. Examples: English, 92: * French. 93: */ 94: public static final ComponentOrientation LEFT_TO_RIGHT 95: = new ComponentOrientation(HORIZONTAL_ID | LEFT_TO_RIGHT_ID); 96: 97: /** 98: * Items run right to left, and lines flow top to bottom. Examples: Arabic, 99: * Hebrew. 100: */ 101: public static final ComponentOrientation RIGHT_TO_LEFT 102: = new ComponentOrientation(HORIZONTAL_ID); 103: 104: /** 105: * The orientation is unknown for the locale. For backwards compatibility, 106: * this behaves like LEFT_TO_RIGHT in the instance methods. 107: */ 108: public static final ComponentOrientation UNKNOWN 109: = new ComponentOrientation(UNKNOWN_ID | HORIZONTAL_ID | LEFT_TO_RIGHT_ID); 110: 111: /** 112: * The orientation of this object; bitwise-or of unknown (1), horizontal (2), 113: * and left-to-right (4). 114: * 115: * @serial the orientation 116: */ 117: private final int orientation; 118: 119: /** 120: * Construct a given orientation. 121: * 122: * @param orientation the orientation 123: */ 124: private ComponentOrientation(int orientation) 125: { 126: this.orientation = orientation; 127: } 128: 129: /** 130: * Returns true if the lines are horizontal, in which case lines flow 131: * top-to-bottom. For example, English, Hebrew. Counterexamples: Japanese, 132: * Chinese, Korean, Mongolian. 133: * 134: * @return true if this orientation has horizontal lines 135: */ 136: public boolean isHorizontal() 137: { 138: return (orientation & HORIZONTAL_ID) != 0; 139: } 140: 141: /** 142: * If isHorizontal() returns true, then this determines whether items in 143: * the line flow left-to-right. If isHorizontal() returns false, items in 144: * a line flow top-to-bottom, and this determines if lines flow 145: * left-to-right. 146: * 147: * @return true if this orientation flows left-to-right 148: */ 149: public boolean isLeftToRight() 150: { 151: return (orientation & LEFT_TO_RIGHT_ID) != 0; 152: } 153: 154: /** 155: * Gets an orientation appropriate for the locale. 156: * 157: * @param locale the locale 158: * @return the orientation for that locale 159: * @throws NullPointerException if locale is null 160: */ 161: public static ComponentOrientation getOrientation(Locale locale) 162: { 163: // Based on iterating over all languages defined in JDK 1.4, this behavior 164: // matches Sun's. However, it makes me wonder if any non-horizontal 165: // orientations even exist, as it sure contradicts their documentation. 166: String language = locale.getLanguage(); 167: if ("ar".equals(language) || "fa".equals(language) || "iw".equals(language) 168: || "ur".equals(language)) 169: return RIGHT_TO_LEFT; 170: return LEFT_TO_RIGHT; 171: } 172: 173: /** 174: * Gets an orientation from a resource bundle. This tries the following: 175: * 176: * <ul> 177: * <li>Use the key "Orientation" to find an instance of ComponentOrientation 178: * in the bundle.</li> 179: * <li>Get the locale of the resource bundle, and get the orientation of 180: * that locale.</li> 181: * <li>Give up and get the orientation of the default locale.</li> 182: * </ul> 183: * 184: * @param bdl the bundle to use 185: * @return the orientation 186: * @throws NullPointerException if bdl is null 187: * @deprecated use {@link #getOrientation(Locale)} instead 188: */ 189: public static ComponentOrientation getOrientation(ResourceBundle bdl) 190: { 191: ComponentOrientation r; 192: try 193: { 194: r = (ComponentOrientation) bdl.getObject("Orientation"); 195: if (r != null) 196: return r; 197: } 198: catch (MissingResourceException ignored) 199: { 200: } 201: catch (ClassCastException ignored) 202: { 203: } 204: try 205: { 206: r = getOrientation(bdl.getLocale()); 207: if (r != null) 208: return r; 209: } 210: catch (Exception ignored) 211: { 212: } 213: return getOrientation(Locale.getDefault()); 214: } 215: } // class ComponentOrientation