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: 46148 $ 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 comparison 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 if (value instanceof Integer) { 149 return (Integer)value > 0 ? Boolean.TRUE : Boolean.FALSE; 150 } 151 return null; 152 } 153 154 public static void notNull(Object value, String name) { 155 if (value == null) { 156 throw new IllegalArgumentException(name + " must be specified"); 157 } 158 } 159 160 public static String[] splitOnCharacter(String value, String needle, int count) { 161 String rc[] = new String[count]; 162 rc[0] = value; 163 for (int i = 1; i < count; i++) { 164 String v = rc[i - 1]; 165 int p = v.indexOf(needle); 166 if (p < 0) { 167 return rc; 168 } 169 rc[i - 1] = v.substring(0, p); 170 rc[i] = v.substring(p + 1); 171 } 172 return rc; 173 } 174 175 /** 176 * Removes any starting characters on the given text which match the given 177 * character 178 * 179 * @param text the string 180 * @param ch the initial characters to remove 181 * @return either the original string or the new substring 182 */ 183 public static String removeStartingCharacters(String text, char ch) { 184 int idx = 0; 185 while (text.charAt(idx) == ch) { 186 idx++; 187 } 188 if (idx > 0) { 189 return text.substring(idx); 190 } 191 return text; 192 } 193 194 public static String capitalize(String text) { 195 if (text == null) { 196 return null; 197 } 198 int length = text.length(); 199 if (length == 0) { 200 return text; 201 } 202 String answer = text.substring(0, 1).toUpperCase(); 203 if (length > 1) { 204 answer += text.substring(1, length); 205 } 206 return answer; 207 } 208 209 210 /** 211 * Returns true if the collection contains the specified value 212 */ 213 @SuppressWarnings("unchecked") 214 public static boolean contains(Object collectionOrArray, Object value) { 215 if (collectionOrArray instanceof Collection) { 216 Collection collection = (Collection)collectionOrArray; 217 return collection.contains(value); 218 } else if (collectionOrArray instanceof String && value instanceof String) { 219 String str = (String) collectionOrArray; 220 String subStr = (String) value; 221 return str.contains(subStr); 222 } else { 223 Iterator iter = createIterator(collectionOrArray); 224 while (iter.hasNext()) { 225 if (equal(value, iter.next())) { 226 return true; 227 } 228 } 229 } 230 return false; 231 } 232 233 /** 234 * Creates an iterator over the value if the value is a collection, an 235 * Object[] or a primitive type array; otherwise to simplify the caller's 236 * code, we just create a singleton collection iterator over a single value 237 */ 238 @SuppressWarnings("unchecked") 239 public static Iterator createIterator(Object value) { 240 if (value == null) { 241 return Collections.EMPTY_LIST.iterator(); 242 } else if (value instanceof Collection) { 243 Collection collection = (Collection)value; 244 return collection.iterator(); 245 } else if (value.getClass().isArray()) { 246 // TODO we should handle primitive array types? 247 List<Object> list = Arrays.asList((Object[]) value); 248 return list.iterator(); 249 } else if (value instanceof NodeList) { 250 // lets iterate through DOM results after performing XPaths 251 final NodeList nodeList = (NodeList) value; 252 return new Iterator<Node>() { 253 int idx = -1; 254 255 public boolean hasNext() { 256 return ++idx < nodeList.getLength(); 257 } 258 259 public Node next() { 260 return nodeList.item(idx); 261 } 262 263 public void remove() { 264 throw new UnsupportedOperationException(); 265 } 266 }; 267 } else { 268 return Collections.singletonList(value).iterator(); 269 } 270 } 271 272 /** 273 * Returns the predicate matching boolean on a {@link List} result set where 274 * if the first element is a boolean its value is used otherwise this method 275 * returns true if the collection is not empty 276 * 277 * @return <tt>true</tt> if the first element is a boolean and its value is true or 278 * if the list is non empty 279 */ 280 public static boolean matches(List list) { 281 if (!list.isEmpty()) { 282 Object value = list.get(0); 283 if (value instanceof Boolean) { 284 Boolean flag = (Boolean)value; 285 return flag.booleanValue(); 286 } else { 287 // lets assume non-empty results are true 288 return true; 289 } 290 } 291 return false; 292 } 293 294 public static boolean isNotNullAndNonEmpty(String text) { 295 return text != null && text.trim().length() > 0; 296 } 297 298 public static boolean isNullOrBlank(String text) { 299 return text == null || text.trim().length() <= 0; 300 } 301 302 /** 303 * A helper method to access a system property, catching any security 304 * exceptions 305 * 306 * @param name the name of the system property required 307 * @param defaultValue the default value to use if the property is not 308 * available or a security exception prevents access 309 * @return the system property value or the default value if the property is 310 * not available or security does not allow its access 311 */ 312 public static String getSystemProperty(String name, String defaultValue) { 313 try { 314 return System.getProperty(name, defaultValue); 315 } catch (Exception e) { 316 if (LOG.isDebugEnabled()) { 317 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, 318 e); 319 } 320 return defaultValue; 321 } 322 } 323 324 /** 325 * A helper method to access a boolean system property, catching any security 326 * exceptions 327 * 328 * @param name the name of the system property required 329 * @param defaultValue the default value to use if the property is not 330 * available or a security exception prevents access 331 * @return the boolean representation of the system property value 332 * or the default value if the property is not available or 333 * security does not allow its access 334 */ 335 public static boolean getSystemProperty(String name, Boolean defaultValue) { 336 String result = getSystemProperty(name, defaultValue.toString()); 337 return Boolean.parseBoolean(result); 338 } 339 340 /** 341 * Returns the type name of the given type or null if the type variable is 342 * null 343 */ 344 public static String name(Class type) { 345 return type != null ? type.getName() : null; 346 } 347 348 /** 349 * Returns the type name of the given value 350 */ 351 public static String className(Object value) { 352 return name(value != null ? value.getClass() : null); 353 } 354 355 /** 356 * Returns the canonical type name of the given value 357 */ 358 public static String classCanonicalName(Object value) { 359 if (value != null) { 360 return value.getClass().getCanonicalName(); 361 } else { 362 return null; 363 } 364 } 365 366 /** 367 * Attempts to load the given class name using the thread context class 368 * loader or the class loader used to load this class 369 * 370 * @param name the name of the class to load 371 * @return the class or null if it could not be loaded 372 */ 373 public static Class<?> loadClass(String name) { 374 return loadClass(name, ObjectHelper.class.getClassLoader()); 375 } 376 377 /** 378 * Attempts to load the given class name using the thread context class 379 * loader or the given class loader 380 * 381 * @param name the name of the class to load 382 * @param loader the class loader to use after the thread context class 383 * loader 384 * @return the class or null if it could not be loaded 385 */ 386 public static Class<?> loadClass(String name, ClassLoader loader) { 387 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 388 if (contextClassLoader != null) { 389 try { 390 return contextClassLoader.loadClass(name); 391 } catch (ClassNotFoundException e) { 392 try { 393 return loader.loadClass(name); 394 } catch (ClassNotFoundException e1) { 395 LOG.debug("Could not find class: " + name + ". Reason: " + e); 396 } 397 } 398 } 399 return null; 400 } 401 402 /** 403 * Attempts to load the given resource as a stream using the thread context class 404 * loader or the class loader used to load this class 405 * 406 * @param name the name of the resource to load 407 * @return the stream or null if it could not be loaded 408 */ 409 public static InputStream loadResourceAsStream(String name) { 410 InputStream in = null; 411 412 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 413 if (contextClassLoader != null) { 414 in = contextClassLoader.getResourceAsStream(name); 415 } 416 if (in == null) { 417 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 418 } 419 420 return in; 421 } 422 423 /** 424 * A helper method to invoke a method via reflection and wrap any exceptions 425 * as {@link RuntimeCamelException} instances 426 * 427 * @param method the method to invoke 428 * @param instance the object instance (or null for static methods) 429 * @param parameters the parameters to the method 430 * @return the result of the method invocation 431 */ 432 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 433 try { 434 return method.invoke(instance, parameters); 435 } catch (IllegalAccessException e) { 436 throw new RuntimeCamelException(e); 437 } catch (InvocationTargetException e) { 438 throw new RuntimeCamelException(e.getCause()); 439 } 440 } 441 442 /** 443 * Returns a list of methods which are annotated with the given annotation 444 * 445 * @param type the type to reflect on 446 * @param annotationType the annotation type 447 * @return a list of the methods found 448 */ 449 public static List<Method> findMethodsWithAnnotation(Class<?> type, 450 Class<? extends Annotation> annotationType) { 451 List<Method> answer = new ArrayList<Method>(); 452 do { 453 Method[] methods = type.getDeclaredMethods(); 454 for (Method method : methods) { 455 if (method.getAnnotation(annotationType) != null) { 456 answer.add(method); 457 } 458 } 459 type = type.getSuperclass(); 460 } while (type != null); 461 return answer; 462 } 463 464 /** 465 * Turns the given object arrays into a meaningful string 466 * 467 * @param objects an array of objects or null 468 * @return a meaningful string 469 */ 470 public static String asString(Object[] objects) { 471 if (objects == null) { 472 return "null"; 473 } else { 474 StringBuffer buffer = new StringBuffer("{"); 475 int counter = 0; 476 for (Object object : objects) { 477 if (counter++ > 0) { 478 buffer.append(", "); 479 } 480 String text = (object == null) ? "null" : object.toString(); 481 buffer.append(text); 482 } 483 buffer.append("}"); 484 return buffer.toString(); 485 } 486 } 487 488 /** 489 * Returns true if a class is assignable from another class like the 490 * {@link Class#isAssignableFrom(Class)} method but which also includes 491 * coercion between primitive types to deal with Java 5 primitive type 492 * wrapping 493 */ 494 public static boolean isAssignableFrom(Class a, Class b) { 495 a = convertPrimitiveTypeToWrapperType(a); 496 b = convertPrimitiveTypeToWrapperType(b); 497 return a.isAssignableFrom(b); 498 } 499 500 /** 501 * Converts primitive types such as int to its wrapper type like 502 * {@link Integer} 503 */ 504 public static Class convertPrimitiveTypeToWrapperType(Class type) { 505 Class rc = type; 506 if (type.isPrimitive()) { 507 if (type == int.class) { 508 rc = Integer.class; 509 } else if (type == long.class) { 510 rc = Long.class; 511 } else if (type == double.class) { 512 rc = Double.class; 513 } else if (type == float.class) { 514 rc = Float.class; 515 } else if (type == short.class) { 516 rc = Short.class; 517 } else if (type == byte.class) { 518 rc = Byte.class; 519 // TODO: Why is boolean disabled 520 /* 521 } else if (type == boolean.class) { 522 rc = Boolean.class; 523 */ 524 } 525 } 526 return rc; 527 } 528 529 /** 530 * Helper method to return the default character set name 531 */ 532 public static String getDefaultCharacterSet() { 533 return Charset.defaultCharset().name(); 534 } 535 536 /** 537 * Returns the Java Bean property name of the given method, if it is a setter 538 */ 539 public static String getPropertyName(Method method) { 540 String propertyName = method.getName(); 541 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 542 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 543 } 544 return propertyName; 545 } 546 547 /** 548 * Returns true if the given collection of annotations matches the given type 549 */ 550 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 551 for (Annotation annotation : annotations) { 552 if (type.isInstance(annotation)) { 553 return true; 554 } 555 } 556 return false; 557 } 558 559 /** 560 * Closes the given resource if it is available, logging any closing exceptions to the given log 561 * 562 * @param closeable the object to close 563 * @param name the name of the resource 564 * @param log the log to use when reporting closure warnings 565 */ 566 public static void close(Closeable closeable, String name, Log log) { 567 if (closeable != null) { 568 try { 569 closeable.close(); 570 } catch (IOException e) { 571 if (log != null) { 572 log.warn("Could not close: " + name + ". Reason: " + e, e); 573 } 574 } 575 } 576 } 577 578 /** 579 * Converts the given value to the required type or throw a meaningful exception 580 */ 581 public static <T> T cast(Class<T> toType, Object value) { 582 if (toType == boolean.class) { 583 return (T)cast(Boolean.class, value); 584 } else if (toType.isPrimitive()) { 585 Class newType = convertPrimitiveTypeToWrapperType(toType); 586 if (newType != toType) { 587 return (T)cast(newType, value); 588 } 589 } 590 try { 591 return toType.cast(value); 592 } catch (ClassCastException e) { 593 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 594 + toType.getName() + " due to: " + e, e); 595 } 596 } 597 598 /** 599 * A helper method to create a new instance of a type using the default constructor arguments. 600 */ 601 public static <T> T newInstance(Class<T> type) { 602 try { 603 return type.newInstance(); 604 } catch (InstantiationException e) { 605 throw new RuntimeCamelException(e.getCause()); 606 } catch (IllegalAccessException e) { 607 throw new RuntimeCamelException(e); 608 } 609 } 610 611 /** 612 * A helper method to create a new instance of a type using the default constructor arguments. 613 */ 614 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 615 try { 616 Object value = actualType.newInstance(); 617 return cast(expectedType, value); 618 } catch (InstantiationException e) { 619 throw new RuntimeCamelException(e.getCause()); 620 } catch (IllegalAccessException e) { 621 throw new RuntimeCamelException(e); 622 } 623 } 624 625 /** 626 * Returns true if the given name is a valid java identifier 627 */ 628 public static boolean isJavaIdentifier(String name) { 629 if (name == null) { 630 return false; 631 } 632 int size = name.length(); 633 if (size < 1) { 634 return false; 635 } 636 if (Character.isJavaIdentifierStart(name.charAt(0))) { 637 for (int i = 1; i < size; i++) { 638 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 639 return false; 640 } 641 } 642 return true; 643 } 644 return false; 645 } 646 647 /** 648 * Returns the type of the given object or null if the value is null 649 */ 650 public static Object type(Object bean) { 651 return bean != null ? bean.getClass() : null; 652 } 653 654 /** 655 * Evaluate the value as a predicate which attempts to convert the value to 656 * a boolean otherwise true is returned if the value is not null 657 */ 658 public static boolean evaluateValuePredicate(Object value) { 659 if (value instanceof Boolean) { 660 Boolean aBoolean = (Boolean)value; 661 return aBoolean.booleanValue(); 662 } 663 return value != null; 664 } 665 }