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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: /** An empty attribute set. */ 55: public static final AttributeSet EMPTY = new SimpleAttributeSet(); 56: 57: /** Storage for the attributes. */ 58: Hashtable tab; 59: 60: /** 61: * Creates a new attribute set that is initially empty. 62: */ 63: public SimpleAttributeSet() 64: { 65: tab = new Hashtable(); 66: } 67: 68: /** 69: * Creates a new <code>SimpleAttributeSet</code> with the same attributes 70: * and resolve parent as the specified set. 71: * 72: * @param a the attributes (<code>null</code> not permitted). 73: * 74: * @throws NullPointerException if <code>a</code> is <code>null</code>. 75: */ 76: public SimpleAttributeSet(AttributeSet a) 77: { 78: tab = new Hashtable(); 79: addAttributes(a); 80: } 81: 82: /** 83: * Adds an attribute with the given <code>name</code> and <code>value</code> 84: * to the set. If the set already contains an attribute with the given 85: * <code>name</code>, the attribute value is updated. 86: * 87: * @param name the attribute name (<code>null</code> not permitted). 88: * @param value the value (<code>null</code> not permitted). 89: * 90: * @throws NullPointerException if either argument is <code>null</code>. 91: */ 92: public void addAttribute(Object name, Object value) 93: { 94: tab.put(name, value); 95: } 96: 97: /** 98: * Adds all the attributes from <code>attributes</code> to this set. 99: * 100: * @param attributes the set of attributes to add (<code>null</code> not 101: * permitted). 102: * 103: * @throws NullPointerException if <code>attributes</code> is 104: * <code>null</code>. 105: */ 106: public void addAttributes(AttributeSet attributes) 107: { 108: Enumeration e = attributes.getAttributeNames(); 109: while (e.hasMoreElements()) 110: { 111: Object name = e.nextElement(); 112: Object val = attributes.getAttribute(name); 113: tab.put(name, val); 114: } 115: } 116: 117: /** 118: * Returns a clone of the attribute set. 119: * 120: * @return A clone of the attribute set. 121: */ 122: public Object clone() 123: { 124: SimpleAttributeSet s = new SimpleAttributeSet(); 125: s.tab = (Hashtable) tab.clone(); 126: return s; 127: } 128: 129: /** 130: * Returns true if the given name and value represent an attribute 131: * found either in this AttributeSet or in its resolve parent hierarchy. 132: * @param name the key for the attribute 133: * @param value the value for the attribute 134: * @return true if the attribute is found here or in this set's resolve 135: * parent hierarchy 136: */ 137: public boolean containsAttribute(Object name, Object value) 138: { 139: if (value == null) 140: throw new NullPointerException("Null 'value' argument."); 141: if (tab.containsKey(name)) 142: return tab.get(name).equals(value); 143: else 144: { 145: AttributeSet p = getResolveParent(); 146: if (p != null) 147: return p.containsAttribute(name, value); 148: else 149: return false; 150: } 151: } 152: 153: /** 154: * Returns true if the given name and value are found in this AttributeSet. 155: * Does not check the resolve parent. 156: * @param name the key for the attribute 157: * @param value the value for the attribute 158: * @return true if the attribute is found in this AttributeSet 159: */ 160: boolean containsAttributeLocally(Object name, Object value) 161: { 162: return tab.containsKey(name) 163: && tab.get(name).equals(value); 164: } 165: 166: /** 167: * Returns <code>true</code> of this <code>AttributeSet</code> contains all 168: * of the specified <code>attributes</code>. 169: * 170: * @param attributes the requested attributes 171: * 172: * @return <code>true</code> of this <code>AttributeSet</code> contains all 173: * of the specified <code>attributes</code> 174: */ 175: public boolean containsAttributes(AttributeSet attributes) 176: { 177: Enumeration e = attributes.getAttributeNames(); 178: while (e.hasMoreElements()) 179: { 180: Object name = e.nextElement(); 181: Object val = attributes.getAttribute(name); 182: if (! containsAttribute(name, val)) 183: return false; 184: } 185: return true; 186: } 187: 188: /** 189: * Creates and returns a copy of this <code>AttributeSet</code>. 190: * 191: * @return a copy of this <code>AttributeSet</code> 192: */ 193: public AttributeSet copyAttributes() 194: { 195: return (AttributeSet) clone(); 196: } 197: 198: /** 199: * Checks this set for equality with an arbitrary object. 200: * 201: * @param obj the object (<code>null</code> permitted). 202: * 203: * @return <code>true</code> if this set is equal to <code>obj</code>, and 204: * <code>false</code> otherwise. 205: */ 206: public boolean equals(Object obj) 207: { 208: return 209: (obj instanceof AttributeSet) 210: && this.isEqual((AttributeSet) obj); 211: } 212: 213: /** 214: * Returns the value of the specified attribute, or <code>null</code> if 215: * there is no attribute with that name. If the attribute is not defined 216: * directly in this set, the parent hierarchy (if there is one) will be 217: * used. 218: * 219: * @param name the attribute (<code>null</code> not permitted). 220: * 221: * @throws NullPointerException if <code>name</code> is <code>null</code>. 222: */ 223: public Object getAttribute(Object name) 224: { 225: Object val = tab.get(name); 226: if (val != null) 227: return val; 228: 229: AttributeSet p = getResolveParent(); 230: if (p != null) 231: return p.getAttribute(name); 232: 233: return null; 234: } 235: 236: /** 237: * Returns the number of attributes stored in this set, plus 1 if a parent 238: * has been specified (the reference to the parent is stored as a special 239: * attribute). The attributes stored in the parent do NOT contribute 240: * to the count. 241: * 242: * @return The attribute count. 243: */ 244: public int getAttributeCount() 245: { 246: return tab.size(); 247: } 248: 249: /** 250: * Returns an enumeration of the attribute names. 251: * 252: * @return An enumeration of the attribute names. 253: */ 254: public Enumeration getAttributeNames() 255: { 256: return tab.keys(); 257: } 258: 259: /** 260: * Returns the resolving parent. 261: * 262: * @return The resolving parent (possibly <code>null</code>). 263: * 264: * @see #setResolveParent(AttributeSet) 265: */ 266: public AttributeSet getResolveParent() 267: { 268: return (AttributeSet) tab.get(ResolveAttribute); 269: } 270: 271: /** 272: * Returns a hash code for this instance. 273: * 274: * @return A hash code. 275: */ 276: public int hashCode() 277: { 278: return tab.hashCode(); 279: } 280: 281: /** 282: * Returns <code>true</code> if the given attribute is defined in this set, 283: * and <code>false</code> otherwise. The parent attribute set is not 284: * checked. 285: * 286: * @param attrName the attribute name (<code>null</code> not permitted). 287: */ 288: public boolean isDefined(Object attrName) 289: { 290: return tab.containsKey(attrName); 291: } 292: 293: /** 294: * Returns <code>true</code> if the set contains no attributes, and 295: * <code>false</code> otherwise. Note that the resolving parent is 296: * stored as an attribute, so this method will return <code>false</code> if 297: * a resolving parent is set. 298: * 299: * @return <code>true</code> if the set contains no attributes, and 300: * <code>false</code> otherwise. 301: */ 302: public boolean isEmpty() 303: { 304: return tab.isEmpty(); 305: } 306: 307: /** 308: * Returns true if the given set has the same number of attributes 309: * as this set and <code>containsAttributes(attr)</code> returns 310: * <code>true</code>. 311: * 312: * @param attr the attribute set (<code>null</code> not permitted). 313: * 314: * @return A boolean. 315: * 316: * @throws NullPointerException if <code>attr</code> is <code>null</code>. 317: */ 318: public boolean isEqual(AttributeSet attr) 319: { 320: return getAttributeCount() == attr.getAttributeCount() 321: && this.containsAttributes(attr); 322: } 323: 324: /** 325: * Removes the attribute with the specified <code>name</code>, if this 326: * attribute is defined. This method will only remove an attribute from 327: * this set, not from the resolving parent. 328: * 329: * @param name the attribute name (<code>null</code> not permitted). 330: * 331: * @throws NullPointerException if <code>name</code> is <code>null</code>. 332: */ 333: public void removeAttribute(Object name) 334: { 335: tab.remove(name); 336: } 337: 338: /** 339: * Removes attributes from this set if they are found in the 340: * given set. Only attributes whose key AND value are removed. 341: * Removes attributes only from this set, not from the resolving parent. 342: * Since the resolving parent is stored as an attribute, if 343: * <code>attributes</code> has the same resolving parent as this set, the 344: * parent will be removed from this set. 345: * 346: * @param attributes the attributes (<code>null</code> not permitted). 347: */ 348: public void removeAttributes(AttributeSet attributes) 349: { 350: Enumeration e = attributes.getAttributeNames(); 351: while (e.hasMoreElements()) 352: { 353: Object name = e.nextElement(); 354: Object val = attributes.getAttribute(name); 355: if (containsAttributeLocally(name, val)) 356: removeAttribute(name); 357: } 358: } 359: 360: /** 361: * Removes the attributes listed in <code>names</code>. 362: * 363: * @param names the attribute names (<code>null</code> not permitted). 364: * 365: * @throws NullPointerException if <code>names</code> is <code>null</code> 366: * or contains any <code>null</code> values. 367: */ 368: public void removeAttributes(Enumeration names) 369: { 370: while (names.hasMoreElements()) 371: { 372: removeAttribute(names.nextElement()); 373: } 374: } 375: 376: /** 377: * Sets the reolving parent for this set. When looking up an attribute, if 378: * it is not found in this set, then the resolving parent is also used for 379: * the lookup. 380: * <p> 381: * Note that the parent is stored as an attribute, and will contribute 1 to 382: * the count returned by {@link #getAttributeCount()}. 383: * 384: * @param parent the parent attribute set (<code>null</code> not permitted). 385: * 386: * @throws NullPointerException if <code>parent</code> is <code>null</code>. 387: * 388: * @see #setResolveParent(AttributeSet) 389: */ 390: public void setResolveParent(AttributeSet parent) 391: { 392: addAttribute(ResolveAttribute, parent); 393: } 394: 395: /** 396: * Returns a string representation of this instance, typically used for 397: * debugging purposes. 398: * 399: * @return A string representation of this instance. 400: */ 401: public String toString() 402: { 403: return tab.toString(); 404: } 405: }
GNU Classpath (0.91) |