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1: /* SimpleAttributeSet.java -- 2: Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc. 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 javax.swing.text; 40: 41: import java.io.Serializable; 42: import java.util.Enumeration; 43: import java.util.Hashtable; 44: 45: /** 46: * A set of attributes. 47: */ 48: public class SimpleAttributeSet 49: implements MutableAttributeSet, Serializable, Cloneable 50: { 51: /** The serialization UID (compatible with JDK1.5). */ 52: private static final long serialVersionUID = 8267656273837665219L; 53: 54: /** 55: * An empty attribute set. 56: */ 57: public static final AttributeSet EMPTY = new EmptyAttributeSet(); 58: 59: /** Storage for the attributes. */ 60: Hashtable tab; 61: 62: /** 63: * Creates a new attribute set that is initially empty. 64: */ 65: public SimpleAttributeSet() 66: { 67: tab = new Hashtable(); 68: } 69: 70: /** 71: * Creates a new <code>SimpleAttributeSet</code> with the same attributes 72: * and resolve parent as the specified set. 73: * 74: * @param a the attributes (<code>null</code> not permitted). 75: * 76: * @throws NullPointerException if <code>a</code> is <code>null</code>. 77: */ 78: public SimpleAttributeSet(AttributeSet a) 79: { 80: tab = new Hashtable(); 81: addAttributes(a); 82: } 83: 84: /** 85: * Adds an attribute with the given <code>name</code> and <code>value</code> 86: * to the set. If the set already contains an attribute with the given 87: * <code>name</code>, the attribute value is updated. 88: * 89: * @param name the attribute name (<code>null</code> not permitted). 90: * @param value the value (<code>null</code> not permitted). 91: * 92: * @throws NullPointerException if either argument is <code>null</code>. 93: */ 94: public void addAttribute(Object name, Object value) 95: { 96: tab.put(name, value); 97: } 98: 99: /** 100: * Adds all the attributes from <code>attributes</code> to this set. 101: * 102: * @param attributes the set of attributes to add (<code>null</code> not 103: * permitted). 104: * 105: * @throws NullPointerException if <code>attributes</code> is 106: * <code>null</code>. 107: */ 108: public void addAttributes(AttributeSet attributes) 109: { 110: Enumeration e = attributes.getAttributeNames(); 111: while (e.hasMoreElements()) 112: { 113: Object name = e.nextElement(); 114: Object val = attributes.getAttribute(name); 115: tab.put(name, val); 116: } 117: } 118: 119: /** 120: * Returns a clone of the attribute set. 121: * 122: * @return A clone of the attribute set. 123: */ 124: public Object clone() 125: { 126: SimpleAttributeSet s = new SimpleAttributeSet(); 127: s.tab = (Hashtable) tab.clone(); 128: return s; 129: } 130: 131: /** 132: * Returns true if the given name and value represent an attribute 133: * found either in this AttributeSet or in its resolve parent hierarchy. 134: * @param name the key for the attribute 135: * @param value the value for the attribute 136: * @return true if the attribute is found here or in this set's resolve 137: * parent hierarchy 138: */ 139: public boolean containsAttribute(Object name, Object value) 140: { 141: if (value == null) 142: throw new NullPointerException("Null 'value' argument."); 143: if (tab.containsKey(name)) 144: return tab.get(name).equals(value); 145: else 146: { 147: AttributeSet p = getResolveParent(); 148: if (p != null) 149: return p.containsAttribute(name, value); 150: else 151: return false; 152: } 153: } 154: 155: /** 156: * Returns true if the given name and value are found in this AttributeSet. 157: * Does not check the resolve parent. 158: * @param name the key for the attribute 159: * @param value the value for the attribute 160: * @return true if the attribute is found in this AttributeSet 161: */ 162: boolean containsAttributeLocally(Object name, Object value) 163: { 164: return tab.containsKey(name) 165: && tab.get(name).equals(value); 166: } 167: 168: /** 169: * Returns <code>true</code> of this <code>AttributeSet</code> contains all 170: * of the specified <code>attributes</code>. 171: * 172: * @param attributes the requested attributes 173: * 174: * @return <code>true</code> of this <code>AttributeSet</code> contains all 175: * of the specified <code>attributes</code> 176: */ 177: public boolean containsAttributes(AttributeSet attributes) 178: { 179: Enumeration e = attributes.getAttributeNames(); 180: while (e.hasMoreElements()) 181: { 182: Object name = e.nextElement(); 183: Object val = attributes.getAttribute(name); 184: if (! containsAttribute(name, val)) 185: return false; 186: } 187: return true; 188: } 189: 190: /** 191: * Creates and returns a copy of this <code>AttributeSet</code>. 192: * 193: * @return a copy of this <code>AttributeSet</code> 194: */ 195: public AttributeSet copyAttributes() 196: { 197: return (AttributeSet) clone(); 198: } 199: 200: /** 201: * Checks this set for equality with an arbitrary object. 202: * 203: * @param obj the object (<code>null</code> permitted). 204: * 205: * @return <code>true</code> if this set is equal to <code>obj</code>, and 206: * <code>false</code> otherwise. 207: */ 208: public boolean equals(Object obj) 209: { 210: return 211: (obj instanceof AttributeSet) 212: && this.isEqual((AttributeSet) obj); 213: } 214: 215: /** 216: * Returns the value of the specified attribute, or <code>null</code> if 217: * there is no attribute with that name. If the attribute is not defined 218: * directly in this set, the parent hierarchy (if there is one) will be 219: * used. 220: * 221: * @param name the attribute (<code>null</code> not permitted). 222: * 223: * @throws NullPointerException if <code>name</code> is <code>null</code>. 224: */ 225: public Object getAttribute(Object name) 226: { 227: Object val = tab.get(name); 228: if (val != null) 229: return val; 230: 231: AttributeSet p = getResolveParent(); 232: if (p != null) 233: return p.getAttribute(name); 234: 235: return null; 236: } 237: 238: /** 239: * Returns the number of attributes stored in this set, plus 1 if a parent 240: * has been specified (the reference to the parent is stored as a special 241: * attribute). The attributes stored in the parent do NOT contribute 242: * to the count. 243: * 244: * @return The attribute count. 245: */ 246: public int getAttributeCount() 247: { 248: return tab.size(); 249: } 250: 251: /** 252: * Returns an enumeration of the attribute names. 253: * 254: * @return An enumeration of the attribute names. 255: */ 256: public Enumeration getAttributeNames() 257: { 258: return tab.keys(); 259: } 260: 261: /** 262: * Returns the resolving parent. 263: * 264: * @return The resolving parent (possibly <code>null</code>). 265: * 266: * @see #setResolveParent(AttributeSet) 267: */ 268: public AttributeSet getResolveParent() 269: { 270: return (AttributeSet) tab.get(ResolveAttribute); 271: } 272: 273: /** 274: * Returns a hash code for this instance. 275: * 276: * @return A hash code. 277: */ 278: public int hashCode() 279: { 280: return tab.hashCode(); 281: } 282: 283: /** 284: * Returns <code>true</code> if the given attribute is defined in this set, 285: * and <code>false</code> otherwise. The parent attribute set is not 286: * checked. 287: * 288: * @param attrName the attribute name (<code>null</code> not permitted). 289: */ 290: public boolean isDefined(Object attrName) 291: { 292: return tab.containsKey(attrName); 293: } 294: 295: /** 296: * Returns <code>true</code> if the set contains no attributes, and 297: * <code>false</code> otherwise. Note that the resolving parent is 298: * stored as an attribute, so this method will return <code>false</code> if 299: * a resolving parent is set. 300: * 301: * @return <code>true</code> if the set contains no attributes, and 302: * <code>false</code> otherwise. 303: */ 304: public boolean isEmpty() 305: { 306: return tab.isEmpty(); 307: } 308: 309: /** 310: * Returns true if the given set has the same number of attributes 311: * as this set and <code>containsAttributes(attr)</code> returns 312: * <code>true</code>. 313: * 314: * @param attr the attribute set (<code>null</code> not permitted). 315: * 316: * @return A boolean. 317: * 318: * @throws NullPointerException if <code>attr</code> is <code>null</code>. 319: */ 320: public boolean isEqual(AttributeSet attr) 321: { 322: return getAttributeCount() == attr.getAttributeCount() 323: && this.containsAttributes(attr); 324: } 325: 326: /** 327: * Removes the attribute with the specified <code>name</code>, if this 328: * attribute is defined. This method will only remove an attribute from 329: * this set, not from the resolving parent. 330: * 331: * @param name the attribute name (<code>null</code> not permitted). 332: * 333: * @throws NullPointerException if <code>name</code> is <code>null</code>. 334: */ 335: public void removeAttribute(Object name) 336: { 337: tab.remove(name); 338: } 339: 340: /** 341: * Removes attributes from this set if they are found in the 342: * given set. Only attributes whose key AND value are removed. 343: * Removes attributes only from this set, not from the resolving parent. 344: * Since the resolving parent is stored as an attribute, if 345: * <code>attributes</code> has the same resolving parent as this set, the 346: * parent will be removed from this set. 347: * 348: * @param attributes the attributes (<code>null</code> not permitted). 349: */ 350: public void removeAttributes(AttributeSet attributes) 351: { 352: Enumeration e = attributes.getAttributeNames(); 353: while (e.hasMoreElements()) 354: { 355: Object name = e.nextElement(); 356: Object val = attributes.getAttribute(name); 357: if (containsAttributeLocally(name, val)) 358: removeAttribute(name); 359: } 360: } 361: 362: /** 363: * Removes the attributes listed in <code>names</code>. 364: * 365: * @param names the attribute names (<code>null</code> not permitted). 366: * 367: * @throws NullPointerException if <code>names</code> is <code>null</code> 368: * or contains any <code>null</code> values. 369: */ 370: public void removeAttributes(Enumeration names) 371: { 372: while (names.hasMoreElements()) 373: { 374: removeAttribute(names.nextElement()); 375: } 376: } 377: 378: /** 379: * Sets the reolving parent for this set. When looking up an attribute, if 380: * it is not found in this set, then the resolving parent is also used for 381: * the lookup. 382: * <p> 383: * Note that the parent is stored as an attribute, and will contribute 1 to 384: * the count returned by {@link #getAttributeCount()}. 385: * 386: * @param parent the parent attribute set (<code>null</code> not permitted). 387: * 388: * @throws NullPointerException if <code>parent</code> is <code>null</code>. 389: * 390: * @see #setResolveParent(AttributeSet) 391: */ 392: public void setResolveParent(AttributeSet parent) 393: { 394: addAttribute(ResolveAttribute, parent); 395: } 396: 397: /** 398: * Returns a string representation of this instance, typically used for 399: * debugging purposes. 400: * 401: * @return A string representation of this instance. 402: */ 403: public String toString() 404: { 405: return tab.toString(); 406: } 407: }