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1: /* ======================================================================== 2: * JCommon : a free general purpose class library for the Java(tm) platform 3: * ======================================================================== 4: * 5: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 6: * 7: * Project Info: http://www.jfree.org/jcommon/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: * ObjectUtilitiess.java 29: * --------------------- 30: * (C) Copyright 2003-2005, by Object Refinery Limited. 31: * 32: * Original Author: David Gilbert (for Object Refinery Limited); 33: * Contributor(s): -; 34: * 35: * $Id: ObjectUtilities.java,v 1.16 2006/07/04 10:20:40 taqua Exp $ 36: * 37: * Changes 38: * ------- 39: * 25-Mar-2003 : Version 1 (DG); 40: * 15-Sep-2003 : Fixed bug in clone(List) method (DG); 41: * 25-Nov-2004 : Modified clone(Object) method to fail with objects that 42: * cannot be cloned, added new deepClone(Collection) method. 43: * Renamed ObjectUtils --> ObjectUtilities (DG); 44: * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG); 45: * 18-Aug-2005 : Added casts to suppress compiler warnings, as suggested in 46: * patch 1260622 (DG); 47: * 48: */ 49: 50: package org.jfree.util; 51: 52: import java.io.IOException; 53: import java.io.InputStream; 54: import java.lang.reflect.InvocationTargetException; 55: import java.lang.reflect.Method; 56: import java.lang.reflect.Modifier; 57: import java.net.URL; 58: import java.util.Collection; 59: import java.util.Iterator; 60: import java.util.ArrayList; 61: import java.util.StringTokenizer; 62: 63: /** 64: * A collection of useful static utility methods for handling classes and object 65: * instantiation. 66: * 67: * @author Thomas Morgner 68: */ 69: public final class ObjectUtilities { 70: 71: /** 72: * A constant for using the TheadContext as source for the classloader. 73: */ 74: public static final String THREAD_CONTEXT = "ThreadContext"; 75: /** 76: * A constant for using the ClassContext as source for the classloader. 77: */ 78: public static final String CLASS_CONTEXT = "ClassContext"; 79: 80: /** 81: * By default use the thread context. 82: */ 83: private static String classLoaderSource = THREAD_CONTEXT; 84: /** 85: * The custom classloader to be used (if not null). 86: */ 87: private static ClassLoader classLoader; 88: 89: /** 90: * Default constructor - private. 91: */ 92: private ObjectUtilities() { 93: } 94: 95: /** 96: * Returns the internal configuration entry, whether the classloader of 97: * the thread context or the context classloader should be used. 98: * 99: * @return the classloader source, either THREAD_CONTEXT or CLASS_CONTEXT. 100: */ 101: public static String getClassLoaderSource() { 102: return classLoaderSource; 103: } 104: 105: /** 106: * Defines the internal configuration entry, whether the classloader of 107: * the thread context or the context classloader should be used. 108: * <p/> 109: * This setting can only be defined using the API, there is no safe way 110: * to put this into an external configuration file. 111: * 112: * @param classLoaderSource the classloader source, 113: * either THREAD_CONTEXT or CLASS_CONTEXT. 114: */ 115: public static void setClassLoaderSource(final String classLoaderSource) { 116: ObjectUtilities.classLoaderSource = classLoaderSource; 117: } 118: 119: /** 120: * Returns <code>true</code> if the two objects are equal OR both 121: * <code>null</code>. 122: * 123: * @param o1 object 1 (<code>null</code> permitted). 124: * @param o2 object 2 (<code>null</code> permitted). 125: * @return <code>true</code> or <code>false</code>. 126: */ 127: public static boolean equal(final Object o1, final Object o2) { 128: if (o1 == o2) { 129: return true; 130: } 131: if (o1 != null) { 132: return o1.equals(o2); 133: } 134: else { 135: return false; 136: } 137: } 138: 139: /** 140: * Returns a hash code for an object, or zero if the object is 141: * <code>null</code>. 142: * 143: * @param object the object (<code>null</code> permitted). 144: * @return The object's hash code (or zero if the object is 145: * <code>null</code>). 146: */ 147: public static int hashCode(final Object object) { 148: int result = 0; 149: if (object != null) { 150: result = object.hashCode(); 151: } 152: return result; 153: } 154: 155: /** 156: * Returns a clone of the specified object, if it can be cloned, otherwise 157: * throws a CloneNotSupportedException. 158: * 159: * @param object the object to clone (<code>null</code> not permitted). 160: * @return A clone of the specified object. 161: * @throws CloneNotSupportedException if the object cannot be cloned. 162: */ 163: public static Object clone(final Object object) 164: throws CloneNotSupportedException { 165: if (object == null) { 166: throw new IllegalArgumentException("Null 'object' argument."); 167: } 168: if (object instanceof PublicCloneable) { 169: final PublicCloneable pc = (PublicCloneable) object; 170: return pc.clone(); 171: } 172: else { 173: try { 174: final Method method = object.getClass().getMethod("clone", 175: (Class[]) null); 176: if (Modifier.isPublic(method.getModifiers())) { 177: return method.invoke(object, (Object[]) null); 178: } 179: } 180: catch (NoSuchMethodException e) { 181: Log.warn("Object without clone() method is impossible."); 182: } 183: catch (IllegalAccessException e) { 184: Log.warn("Object.clone(): unable to call method."); 185: } 186: catch (InvocationTargetException e) { 187: Log.warn("Object without clone() method is impossible."); 188: } 189: } 190: throw new CloneNotSupportedException("Failed to clone."); 191: } 192: 193: /** 194: * Returns a new collection containing clones of all the items in the 195: * specified collection. 196: * 197: * @param collection the collection (<code>null</code> not permitted). 198: * @return A new collection containing clones of all the items in the 199: * specified collection. 200: * @throws CloneNotSupportedException if any of the items in the collection 201: * cannot be cloned. 202: */ 203: public static Collection deepClone(final Collection collection) 204: throws CloneNotSupportedException { 205: 206: if (collection == null) { 207: throw new IllegalArgumentException("Null 'collection' argument."); 208: } 209: // all JDK-Collections are cloneable ... 210: // and if the collection is not clonable, then we should throw 211: // a CloneNotSupportedException anyway ... 212: final Collection result 213: = (Collection) ObjectUtilities.clone(collection); 214: result.clear(); 215: final Iterator iterator = collection.iterator(); 216: while (iterator.hasNext()) { 217: final Object item = iterator.next(); 218: if (item != null) { 219: result.add(clone(item)); 220: } 221: else { 222: result.add(null); 223: } 224: } 225: return result; 226: } 227: 228: /** 229: * Redefines the custom classloader. 230: * 231: * @param classLoader the new classloader or null to use the default. 232: */ 233: public synchronized static void setClassLoader( 234: final ClassLoader classLoader) { 235: ObjectUtilities.classLoader = classLoader; 236: } 237: 238: /** 239: * Returns the custom classloader or null, if no custom classloader is defined. 240: * 241: * @return the custom classloader or null to use the default. 242: */ 243: public static ClassLoader getClassLoader() { 244: return classLoader; 245: } 246: 247: /** 248: * Returns the classloader, which was responsible for loading the given 249: * class. 250: * 251: * @param c the classloader, either an application class loader or the 252: * boot loader. 253: * @return the classloader, never null. 254: * @throws SecurityException if the SecurityManager does not allow to grab 255: * the context classloader. 256: */ 257: public synchronized static ClassLoader getClassLoader(final Class c) { 258: if (classLoader != null) { 259: return classLoader; 260: } 261: if ("ThreadContext".equals(classLoaderSource)) { 262: final ClassLoader threadLoader 263: = Thread.currentThread().getContextClassLoader(); 264: if (threadLoader != null) { 265: return threadLoader; 266: } 267: } 268: 269: // Context classloader - do not cache .. 270: final ClassLoader applicationCL = c.getClassLoader(); 271: if (applicationCL == null) { 272: return ClassLoader.getSystemClassLoader(); 273: } 274: else { 275: return applicationCL; 276: } 277: } 278: 279: 280: /** 281: * Returns the resource specified by the <strong>absolute</strong> name. 282: * 283: * @param name the name of the resource 284: * @param c the source class 285: * @return the url of the resource or null, if not found. 286: */ 287: public static URL getResource(final String name, final Class c) { 288: final ClassLoader cl = getClassLoader(c); 289: if (cl == null) { 290: return null; 291: } 292: return cl.getResource(name); 293: } 294: 295: /** 296: * Returns the resource specified by the <strong>relative</strong> name. 297: * 298: * @param name the name of the resource relative to the given class 299: * @param c the source class 300: * @return the url of the resource or null, if not found. 301: */ 302: public static URL getResourceRelative(final String name, final Class c) { 303: final ClassLoader cl = getClassLoader(c); 304: final String cname = convertName(name, c); 305: if (cl == null) { 306: return null; 307: } 308: return cl.getResource(cname); 309: } 310: 311: /** 312: * Transform the class-relative resource name into a global name by 313: * appending it to the classes package name. If the name is already a 314: * global name (the name starts with a "/"), then the name is returned 315: * unchanged. 316: * 317: * @param name the resource name 318: * @param c the class which the resource is relative to 319: * @return the tranformed name. 320: */ 321: private static String convertName(final String name, Class c) { 322: if (name.startsWith("/")) { 323: // strip leading slash.. 324: return name.substring(1); 325: } 326: 327: // we cant work on arrays, so remove them ... 328: while (c.isArray()) { 329: c = c.getComponentType(); 330: } 331: // extract the package ... 332: final String baseName = c.getName(); 333: final int index = baseName.lastIndexOf('.'); 334: if (index == -1) { 335: return name; 336: } 337: 338: final String pkgName = baseName.substring(0, index); 339: return pkgName.replace('.', '/') + "/" + name; 340: } 341: 342: /** 343: * Returns the inputstream for the resource specified by the 344: * <strong>absolute</strong> name. 345: * 346: * @param name the name of the resource 347: * @param context the source class 348: * @return the url of the resource or null, if not found. 349: */ 350: public static InputStream getResourceAsStream(final String name, 351: final Class context) { 352: final URL url = getResource(name, context); 353: if (url == null) { 354: return null; 355: } 356: 357: try { 358: return url.openStream(); 359: } 360: catch (IOException e) { 361: return null; 362: } 363: } 364: 365: /** 366: * Returns the inputstream for the resource specified by the 367: * <strong>relative</strong> name. 368: * 369: * @param name the name of the resource relative to the given class 370: * @param context the source class 371: * @return the url of the resource or null, if not found. 372: */ 373: public static InputStream getResourceRelativeAsStream 374: (final String name, final Class context) { 375: final URL url = getResourceRelative(name, context); 376: if (url == null) { 377: return null; 378: } 379: 380: try { 381: return url.openStream(); 382: } 383: catch (IOException e) { 384: return null; 385: } 386: } 387: 388: /** 389: * Tries to create a new instance of the given class. This is a short cut 390: * for the common bean instantiation code. 391: * 392: * @param className the class name as String, never null. 393: * @param source the source class, from where to get the classloader. 394: * @return the instantiated object or null, if an error occured. 395: */ 396: public static Object loadAndInstantiate(final String className, 397: final Class source) { 398: try { 399: final ClassLoader loader = getClassLoader(source); 400: final Class c = loader.loadClass(className); 401: return c.newInstance(); 402: } 403: catch (Exception e) { 404: return null; 405: } 406: } 407: 408: 409: public static boolean isJDK14() { 410: final ClassLoader loader = getClassLoader(ObjectUtilities.class); 411: if (loader != null) { 412: try { 413: loader.loadClass("java.util.RandomAccess"); 414: return true; 415: } 416: catch (ClassNotFoundException e) { 417: return false; 418: } 419: catch(Exception e) { 420: // do nothing, but do not crash ... 421: } 422: } 423: // OK, the quick and dirty, but secure way failed. Lets try it 424: // using the standard way. 425: try { 426: final String version = System.getProperty 427: ("java.vm.specification.version"); 428: // parse the beast... 429: if (version == null) { 430: return false; 431: } 432: 433: String[] versions = parseVersions(version); 434: String[] target = new String[]{ "1", "4" }; 435: return (ArrayUtilities.compareVersionArrays(versions, target) >= 0); 436: } 437: catch(Exception e) { 438: return false; 439: } 440: } 441: 442: private static String[] parseVersions (String version) 443: { 444: if (version == null) 445: { 446: return new String[0]; 447: } 448: 449: final ArrayList versions = new ArrayList(); 450: StringTokenizer strtok = new StringTokenizer(version, "."); 451: while (strtok.hasMoreTokens()) 452: { 453: versions.add (strtok.nextToken()); 454: } 455: return (String[]) versions.toArray(new String[versions.size()]); 456: } 457: }