001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.camel.util; 018 019 import java.io.Closeable; 020 import java.io.IOException; 021 import java.io.InputStream; 022 import java.lang.annotation.Annotation; 023 import java.lang.reflect.InvocationTargetException; 024 import java.lang.reflect.Method; 025 import java.nio.charset.Charset; 026 import java.util.ArrayList; 027 import java.util.Arrays; 028 import java.util.Collection; 029 import java.util.Collections; 030 import java.util.Iterator; 031 import java.util.List; 032 033 import org.w3c.dom.Node; 034 import org.w3c.dom.NodeList; 035 036 037 import org.apache.camel.RuntimeCamelException; 038 import org.apache.commons.logging.Log; 039 import org.apache.commons.logging.LogFactory; 040 041 042 /** 043 * A number of useful helper methods for working with Objects 044 * 045 * @version $Revision: 42401 $ 046 */ 047 public final class ObjectHelper { 048 private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class); 049 050 /** 051 * Utility classes should not have a public constructor. 052 */ 053 private ObjectHelper() { 054 } 055 056 /** 057 * @deprecated use the equal method instead. Will be removed in Camel 2.0. 058 * 059 * @see #equal(Object, Object) 060 */ 061 @Deprecated 062 public static boolean equals(Object a, Object b) { 063 return equal(a, b); 064 } 065 066 /** 067 * A helper method for comparing objects for equality while handling nulls 068 */ 069 public static boolean equal(Object a, Object b) { 070 if (a == b) { 071 return true; 072 } 073 074 if (a instanceof byte[] && b instanceof byte[]) { 075 return equalByteArray((byte[]) a, (byte[]) b); 076 } 077 078 return a != null && b != null && a.equals(b); 079 } 080 081 /** 082 * A helper method for comparing byte arrays for equality while handling nulls 083 */ 084 public static boolean equalByteArray(byte[] a, byte[] b) { 085 if (a == b) { 086 return true; 087 } 088 089 // loop and compare each byte 090 if (a != null && b != null && a.length == b.length) { 091 for (int i = 0; i < a.length; i++) { 092 if (a[i] != b[i]) { 093 return false; 094 } 095 } 096 // all bytes are equal 097 return true; 098 } 099 100 return false; 101 } 102 103 /** 104 * Returns true if the given object is equal to any of the expected value 105 */ 106 public static boolean isEqualToAny(Object object, Object... values) { 107 for (Object value : values) { 108 if (equal(object, value)) { 109 return true; 110 } 111 } 112 return false; 113 } 114 115 /** 116 * A helper method for performing an ordered comparsion on the objects 117 * handling nulls and objects which do not handle sorting gracefully 118 */ 119 public static int compare(Object a, Object b) { 120 if (a == b) { 121 return 0; 122 } 123 if (a == null) { 124 return -1; 125 } 126 if (b == null) { 127 return 1; 128 } 129 if (a instanceof Comparable) { 130 Comparable comparable = (Comparable)a; 131 return comparable.compareTo(b); 132 } else { 133 int answer = a.getClass().getName().compareTo(b.getClass().getName()); 134 if (answer == 0) { 135 answer = a.hashCode() - b.hashCode(); 136 } 137 return answer; 138 } 139 } 140 141 public static Boolean toBoolean(Object value) { 142 if (value instanceof Boolean) { 143 return (Boolean)value; 144 } 145 if (value instanceof String) { 146 return "true".equalsIgnoreCase(value.toString()) ? Boolean.TRUE : Boolean.FALSE; 147 } 148 return null; 149 } 150 151 public static void notNull(Object value, String name) { 152 if (value == null) { 153 throw new IllegalArgumentException(name + " must be specified"); 154 } 155 } 156 157 public static String[] splitOnCharacter(String value, String needle, int count) { 158 String rc[] = new String[count]; 159 rc[0] = value; 160 for (int i = 1; i < count; i++) { 161 String v = rc[i - 1]; 162 int p = v.indexOf(needle); 163 if (p < 0) { 164 return rc; 165 } 166 rc[i - 1] = v.substring(0, p); 167 rc[i] = v.substring(p + 1); 168 } 169 return rc; 170 } 171 172 /** 173 * Removes any starting characters on the given text which match the given 174 * character 175 * 176 * @param text the string 177 * @param ch the initial characters to remove 178 * @return either the original string or the new substring 179 */ 180 public static String removeStartingCharacters(String text, char ch) { 181 int idx = 0; 182 while (text.charAt(idx) == ch) { 183 idx++; 184 } 185 if (idx > 0) { 186 return text.substring(idx); 187 } 188 return text; 189 } 190 191 public static String capitalize(String text) { 192 if (text == null) { 193 return null; 194 } 195 int length = text.length(); 196 if (length == 0) { 197 return text; 198 } 199 String answer = text.substring(0, 1).toUpperCase(); 200 if (length > 1) { 201 answer += text.substring(1, length); 202 } 203 return answer; 204 } 205 206 207 /** 208 * Returns true if the collection contains the specified value 209 */ 210 @SuppressWarnings("unchecked") 211 public static boolean contains(Object collectionOrArray, Object value) { 212 if (collectionOrArray instanceof Collection) { 213 Collection collection = (Collection)collectionOrArray; 214 return collection.contains(value); 215 } else if (collectionOrArray instanceof String && value instanceof String) { 216 String str = (String) collectionOrArray; 217 String subStr = (String) value; 218 return str.contains(subStr); 219 } else { 220 Iterator iter = createIterator(collectionOrArray); 221 while (iter.hasNext()) { 222 if (equal(value, iter.next())) { 223 return true; 224 } 225 } 226 } 227 return false; 228 } 229 230 /** 231 * Creates an iterator over the value if the value is a collection, an 232 * Object[] or a primitive type array; otherwise to simplify the caller's 233 * code, we just create a singleton collection iterator over a single value 234 */ 235 @SuppressWarnings("unchecked") 236 public static Iterator createIterator(Object value) { 237 if (value == null) { 238 return Collections.EMPTY_LIST.iterator(); 239 } else if (value instanceof Collection) { 240 Collection collection = (Collection)value; 241 return collection.iterator(); 242 } else if (value.getClass().isArray()) { 243 // TODO we should handle primitive array types? 244 List<Object> list = Arrays.asList((Object[]) value); 245 return list.iterator(); 246 } else if (value instanceof NodeList) { 247 // lets iterate through DOM results after performing XPaths 248 final NodeList nodeList = (NodeList) value; 249 return new Iterator<Node>() { 250 int idx = -1; 251 252 public boolean hasNext() { 253 return ++idx < nodeList.getLength(); 254 } 255 256 public Node next() { 257 return nodeList.item(idx); 258 } 259 260 public void remove() { 261 throw new UnsupportedOperationException(); 262 } 263 }; 264 } else { 265 return Collections.singletonList(value).iterator(); 266 } 267 } 268 269 /** 270 * Returns the predicate matching boolean on a {@link List} result set where 271 * if the first element is a boolean its value is used otherwise this method 272 * returns true if the collection is not empty 273 * 274 * @return <tt>true</tt> if the first element is a boolean and its value is true or 275 * if the list is non empty 276 */ 277 public static boolean matches(List list) { 278 if (!list.isEmpty()) { 279 Object value = list.get(0); 280 if (value instanceof Boolean) { 281 Boolean flag = (Boolean)value; 282 return flag.booleanValue(); 283 } else { 284 // lets assume non-empty results are true 285 return true; 286 } 287 } 288 return false; 289 } 290 291 public static boolean isNotNullAndNonEmpty(String text) { 292 return text != null && text.trim().length() > 0; 293 } 294 295 public static boolean isNullOrBlank(String text) { 296 return text == null || text.trim().length() <= 0; 297 } 298 299 /** 300 * A helper method to access a system property, catching any security 301 * exceptions 302 * 303 * @param name the name of the system property required 304 * @param defaultValue the default value to use if the property is not 305 * available or a security exception prevents access 306 * @return the system property value or the default value if the property is 307 * not available or security does not allow its access 308 */ 309 public static String getSystemProperty(String name, String defaultValue) { 310 try { 311 return System.getProperty(name, defaultValue); 312 } catch (Exception e) { 313 if (LOG.isDebugEnabled()) { 314 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, 315 e); 316 } 317 return defaultValue; 318 } 319 } 320 321 /** 322 * Returns the type name of the given type or null if the type variable is 323 * null 324 */ 325 public static String name(Class type) { 326 return type != null ? type.getName() : null; 327 } 328 329 /** 330 * Returns the type name of the given value 331 */ 332 public static String className(Object value) { 333 return name(value != null ? value.getClass() : null); 334 } 335 336 /** 337 * Attempts to load the given class name using the thread context class 338 * loader or the class loader used to load this class 339 * 340 * @param name the name of the class to load 341 * @return the class or null if it could not be loaded 342 */ 343 public static Class<?> loadClass(String name) { 344 return loadClass(name, ObjectHelper.class.getClassLoader()); 345 } 346 347 /** 348 * Attempts to load the given class name using the thread context class 349 * loader or the given class loader 350 * 351 * @param name the name of the class to load 352 * @param loader the class loader to use after the thread context class 353 * loader 354 * @return the class or null if it could not be loaded 355 */ 356 public static Class<?> loadClass(String name, ClassLoader loader) { 357 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 358 if (contextClassLoader != null) { 359 try { 360 return contextClassLoader.loadClass(name); 361 } catch (ClassNotFoundException e) { 362 try { 363 return loader.loadClass(name); 364 } catch (ClassNotFoundException e1) { 365 LOG.debug("Could not find class: " + name + ". Reason: " + e); 366 } 367 } 368 } 369 return null; 370 } 371 372 /** 373 * Attempts to load the given resource as a stream using the thread context class 374 * loader or the class loader used to load this class 375 * 376 * @param name the name of the resource to load 377 * @return the stream or null if it could not be loaded 378 */ 379 public static InputStream loadResourceAsStream(String name) { 380 InputStream in = null; 381 382 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 383 if (contextClassLoader != null) { 384 in = contextClassLoader.getResourceAsStream(name); 385 } 386 if (in == null) { 387 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 388 } 389 390 return in; 391 } 392 393 /** 394 * A helper method to invoke a method via reflection and wrap any exceptions 395 * as {@link RuntimeCamelException} instances 396 * 397 * @param method the method to invoke 398 * @param instance the object instance (or null for static methods) 399 * @param parameters the parameters to the method 400 * @return the result of the method invocation 401 */ 402 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 403 try { 404 return method.invoke(instance, parameters); 405 } catch (IllegalAccessException e) { 406 throw new RuntimeCamelException(e); 407 } catch (InvocationTargetException e) { 408 throw new RuntimeCamelException(e.getCause()); 409 } 410 } 411 412 /** 413 * Returns a list of methods which are annotated with the given annotation 414 * 415 * @param type the type to reflect on 416 * @param annotationType the annotation type 417 * @return a list of the methods found 418 */ 419 public static List<Method> findMethodsWithAnnotation(Class<?> type, 420 Class<? extends Annotation> annotationType) { 421 List<Method> answer = new ArrayList<Method>(); 422 do { 423 Method[] methods = type.getDeclaredMethods(); 424 for (Method method : methods) { 425 if (method.getAnnotation(annotationType) != null) { 426 answer.add(method); 427 } 428 } 429 type = type.getSuperclass(); 430 } while (type != null); 431 return answer; 432 } 433 434 /** 435 * Turns the given object arrays into a meaningful string 436 * 437 * @param objects an array of objects or null 438 * @return a meaningful string 439 */ 440 public static String asString(Object[] objects) { 441 if (objects == null) { 442 return "null"; 443 } else { 444 StringBuffer buffer = new StringBuffer("{"); 445 int counter = 0; 446 for (Object object : objects) { 447 if (counter++ > 0) { 448 buffer.append(", "); 449 } 450 String text = (object == null) ? "null" : object.toString(); 451 buffer.append(text); 452 } 453 buffer.append("}"); 454 return buffer.toString(); 455 } 456 } 457 458 /** 459 * Returns true if a class is assignable from another class like the 460 * {@link Class#isAssignableFrom(Class)} method but which also includes 461 * coercion between primitive types to deal with Java 5 primitive type 462 * wrapping 463 */ 464 public static boolean isAssignableFrom(Class a, Class b) { 465 a = convertPrimitiveTypeToWrapperType(a); 466 b = convertPrimitiveTypeToWrapperType(b); 467 return a.isAssignableFrom(b); 468 } 469 470 /** 471 * Converts primitive types such as int to its wrapper type like 472 * {@link Integer} 473 */ 474 public static Class convertPrimitiveTypeToWrapperType(Class type) { 475 Class rc = type; 476 if (type.isPrimitive()) { 477 if (type == int.class) { 478 rc = Integer.class; 479 } else if (type == long.class) { 480 rc = Long.class; 481 } else if (type == double.class) { 482 rc = Double.class; 483 } else if (type == float.class) { 484 rc = Float.class; 485 } else if (type == short.class) { 486 rc = Short.class; 487 } else if (type == byte.class) { 488 rc = Byte.class; 489 // TODO: Why is boolean disabled 490 /* 491 } else if (type == boolean.class) { 492 rc = Boolean.class; 493 */ 494 } 495 } 496 return rc; 497 } 498 499 /** 500 * Helper method to return the default character set name 501 */ 502 public static String getDefaultCharacterSet() { 503 return Charset.defaultCharset().name(); 504 } 505 506 /** 507 * Returns the Java Bean property name of the given method, if it is a setter 508 */ 509 public static String getPropertyName(Method method) { 510 String propertyName = method.getName(); 511 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 512 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 513 } 514 return propertyName; 515 } 516 517 /** 518 * Returns true if the given collection of annotations matches the given type 519 */ 520 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 521 for (Annotation annotation : annotations) { 522 if (type.isInstance(annotation)) { 523 return true; 524 } 525 } 526 return false; 527 } 528 529 /** 530 * Closes the given resource if it is available, logging any closing exceptions to the given log 531 * 532 * @param closeable the object to close 533 * @param name the name of the resource 534 * @param log the log to use when reporting closure warnings 535 */ 536 public static void close(Closeable closeable, String name, Log log) { 537 if (closeable != null) { 538 try { 539 closeable.close(); 540 } catch (IOException e) { 541 if (log != null) { 542 log.warn("Could not close: " + name + ". Reason: " + e, e); 543 } 544 } 545 } 546 } 547 548 /** 549 * Converts the given value to the required type or throw a meaningful exception 550 */ 551 public static <T> T cast(Class<T> toType, Object value) { 552 if (toType == boolean.class) { 553 return (T)cast(Boolean.class, value); 554 } else if (toType.isPrimitive()) { 555 Class newType = convertPrimitiveTypeToWrapperType(toType); 556 if (newType != toType) { 557 return (T)cast(newType, value); 558 } 559 } 560 try { 561 return toType.cast(value); 562 } catch (ClassCastException e) { 563 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 564 + toType.getName() + " due to: " + e, e); 565 } 566 } 567 568 /** 569 * A helper method to create a new instance of a type using the default constructor arguments. 570 */ 571 public static <T> T newInstance(Class<T> type) { 572 try { 573 return type.newInstance(); 574 } catch (InstantiationException e) { 575 throw new RuntimeCamelException(e.getCause()); 576 } catch (IllegalAccessException e) { 577 throw new RuntimeCamelException(e); 578 } 579 } 580 581 /** 582 * A helper method to create a new instance of a type using the default constructor arguments. 583 */ 584 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 585 try { 586 Object value = actualType.newInstance(); 587 return cast(expectedType, value); 588 } catch (InstantiationException e) { 589 throw new RuntimeCamelException(e.getCause()); 590 } catch (IllegalAccessException e) { 591 throw new RuntimeCamelException(e); 592 } 593 } 594 595 /** 596 * Returns true if the given name is a valid java identifier 597 */ 598 public static boolean isJavaIdentifier(String name) { 599 if (name == null) { 600 return false; 601 } 602 int size = name.length(); 603 if (size < 1) { 604 return false; 605 } 606 if (Character.isJavaIdentifierStart(name.charAt(0))) { 607 for (int i = 1; i < size; i++) { 608 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 609 return false; 610 } 611 } 612 return true; 613 } 614 return false; 615 } 616 617 /** 618 * Returns the type of the given object or null if the value is null 619 */ 620 public static Object type(Object bean) { 621 return bean != null ? bean.getClass() : null; 622 } 623 624 /** 625 * Evaluate the value as a predicate which attempts to convert the value to 626 * a boolean otherwise true is returned if the value is not null 627 */ 628 public static boolean evaluateValuePredicate(Object value) { 629 if (value instanceof Boolean) { 630 Boolean aBoolean = (Boolean)value; 631 return aBoolean.booleanValue(); 632 } 633 return value != null; 634 } 635 }