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.AnnotatedElement; 024 import java.lang.reflect.InvocationTargetException; 025 import java.lang.reflect.Method; 026 import java.nio.charset.Charset; 027 import java.util.ArrayList; 028 import java.util.Arrays; 029 import java.util.Collection; 030 import java.util.Collections; 031 import java.util.Iterator; 032 import java.util.List; 033 034 import org.w3c.dom.Node; 035 import org.w3c.dom.NodeList; 036 037 038 import org.apache.camel.RuntimeCamelException; 039 import org.apache.commons.logging.Log; 040 import org.apache.commons.logging.LogFactory; 041 042 043 /** 044 * A number of useful helper methods for working with Objects 045 * 046 * @version $Revision: 707294 $ 047 */ 048 public final class ObjectHelper { 049 private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class); 050 051 /** 052 * Utility classes should not have a public constructor. 053 */ 054 private ObjectHelper() { 055 } 056 057 /** 058 * @deprecated use the equal method instead. Will be removed in Camel 2.0. 059 * 060 * @see #equal(Object, Object) 061 */ 062 @Deprecated 063 public static boolean equals(Object a, Object b) { 064 return equal(a, b); 065 } 066 067 /** 068 * A helper method for comparing objects for equality while handling nulls 069 */ 070 public static boolean equal(Object a, Object b) { 071 if (a == b) { 072 return true; 073 } 074 075 if (a instanceof byte[] && b instanceof byte[]) { 076 return equalByteArray((byte[]) a, (byte[]) b); 077 } 078 079 return a != null && b != null && a.equals(b); 080 } 081 082 /** 083 * A helper method for comparing byte arrays for equality while handling nulls 084 */ 085 public static boolean equalByteArray(byte[] a, byte[] b) { 086 if (a == b) { 087 return true; 088 } 089 090 // loop and compare each byte 091 if (a != null && b != null && a.length == b.length) { 092 for (int i = 0; i < a.length; i++) { 093 if (a[i] != b[i]) { 094 return false; 095 } 096 } 097 // all bytes are equal 098 return true; 099 } 100 101 return false; 102 } 103 104 /** 105 * Returns true if the given object is equal to any of the expected value 106 */ 107 public static boolean isEqualToAny(Object object, Object... values) { 108 for (Object value : values) { 109 if (equal(object, value)) { 110 return true; 111 } 112 } 113 return false; 114 } 115 116 /** 117 * A helper method for performing an ordered comparison on the objects 118 * handling nulls and objects which do not handle sorting gracefully 119 */ 120 public static int compare(Object a, Object b) { 121 if (a == b) { 122 return 0; 123 } 124 if (a == null) { 125 return -1; 126 } 127 if (b == null) { 128 return 1; 129 } 130 if (a instanceof Comparable) { 131 Comparable comparable = (Comparable)a; 132 return comparable.compareTo(b); 133 } else { 134 int answer = a.getClass().getName().compareTo(b.getClass().getName()); 135 if (answer == 0) { 136 answer = a.hashCode() - b.hashCode(); 137 } 138 return answer; 139 } 140 } 141 142 public static Boolean toBoolean(Object value) { 143 if (value instanceof Boolean) { 144 return (Boolean)value; 145 } 146 if (value instanceof String) { 147 return "true".equalsIgnoreCase(value.toString()) ? Boolean.TRUE : Boolean.FALSE; 148 } 149 if (value instanceof Integer) { 150 return (Integer)value > 0 ? Boolean.TRUE : Boolean.FALSE; 151 } 152 return null; 153 } 154 155 public static void notNull(Object value, String name) { 156 if (value == null) { 157 throw new IllegalArgumentException(name + " must be specified"); 158 } 159 } 160 161 public static String[] splitOnCharacter(String value, String needle, int count) { 162 String rc[] = new String[count]; 163 rc[0] = value; 164 for (int i = 1; i < count; i++) { 165 String v = rc[i - 1]; 166 int p = v.indexOf(needle); 167 if (p < 0) { 168 return rc; 169 } 170 rc[i - 1] = v.substring(0, p); 171 rc[i] = v.substring(p + 1); 172 } 173 return rc; 174 } 175 176 /** 177 * Removes any starting characters on the given text which match the given 178 * character 179 * 180 * @param text the string 181 * @param ch the initial characters to remove 182 * @return either the original string or the new substring 183 */ 184 public static String removeStartingCharacters(String text, char ch) { 185 int idx = 0; 186 while (text.charAt(idx) == ch) { 187 idx++; 188 } 189 if (idx > 0) { 190 return text.substring(idx); 191 } 192 return text; 193 } 194 195 public static String capitalize(String text) { 196 if (text == null) { 197 return null; 198 } 199 int length = text.length(); 200 if (length == 0) { 201 return text; 202 } 203 String answer = text.substring(0, 1).toUpperCase(); 204 if (length > 1) { 205 answer += text.substring(1, length); 206 } 207 return answer; 208 } 209 210 211 /** 212 * Returns true if the collection contains the specified value 213 */ 214 @SuppressWarnings("unchecked") 215 public static boolean contains(Object collectionOrArray, Object value) { 216 if (collectionOrArray instanceof Collection) { 217 Collection collection = (Collection)collectionOrArray; 218 return collection.contains(value); 219 } else if (collectionOrArray instanceof String && value instanceof String) { 220 String str = (String) collectionOrArray; 221 String subStr = (String) value; 222 return str.contains(subStr); 223 } else { 224 Iterator iter = createIterator(collectionOrArray); 225 while (iter.hasNext()) { 226 if (equal(value, iter.next())) { 227 return true; 228 } 229 } 230 } 231 return false; 232 } 233 234 /** 235 * Creates an iterator over the value if the value is a collection, an 236 * Object[] or a primitive type array; otherwise to simplify the caller's 237 * code, we just create a singleton collection iterator over a single value 238 */ 239 @SuppressWarnings("unchecked") 240 public static Iterator createIterator(Object value) { 241 if (value == null) { 242 return Collections.EMPTY_LIST.iterator(); 243 } else if (value instanceof Iterator) { 244 return (Iterator) value; 245 } else if (value instanceof Collection) { 246 Collection collection = (Collection)value; 247 return collection.iterator(); 248 } else if (value.getClass().isArray()) { 249 // TODO we should handle primitive array types? 250 List<Object> list = Arrays.asList((Object[]) value); 251 return list.iterator(); 252 } else if (value instanceof NodeList) { 253 // lets iterate through DOM results after performing XPaths 254 final NodeList nodeList = (NodeList) value; 255 return new Iterator<Node>() { 256 int idx = -1; 257 258 public boolean hasNext() { 259 return ++idx < nodeList.getLength(); 260 } 261 262 public Node next() { 263 return nodeList.item(idx); 264 } 265 266 public void remove() { 267 throw new UnsupportedOperationException(); 268 } 269 }; 270 } else { 271 return Collections.singletonList(value).iterator(); 272 } 273 } 274 275 /** 276 * Returns the predicate matching boolean on a {@link List} result set where 277 * if the first element is a boolean its value is used otherwise this method 278 * returns true if the collection is not empty 279 * 280 * @return <tt>true</tt> if the first element is a boolean and its value is true or 281 * if the list is non empty 282 */ 283 public static boolean matches(List list) { 284 if (!list.isEmpty()) { 285 Object value = list.get(0); 286 if (value instanceof Boolean) { 287 Boolean flag = (Boolean)value; 288 return flag.booleanValue(); 289 } else { 290 // lets assume non-empty results are true 291 return true; 292 } 293 } 294 return false; 295 } 296 297 public static boolean isNotNullAndNonEmpty(String text) { 298 return text != null && text.trim().length() > 0; 299 } 300 301 public static boolean isNullOrBlank(String text) { 302 return text == null || text.trim().length() <= 0; 303 } 304 305 /** 306 * A helper method to access a system property, catching any security 307 * exceptions 308 * 309 * @param name the name of the system property required 310 * @param defaultValue the default value to use if the property is not 311 * available or a security exception prevents access 312 * @return the system property value or the default value if the property is 313 * not available or security does not allow its access 314 */ 315 public static String getSystemProperty(String name, String defaultValue) { 316 try { 317 return System.getProperty(name, defaultValue); 318 } catch (Exception e) { 319 if (LOG.isDebugEnabled()) { 320 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, 321 e); 322 } 323 return defaultValue; 324 } 325 } 326 327 /** 328 * A helper method to access a boolean system property, catching any security 329 * exceptions 330 * 331 * @param name the name of the system property required 332 * @param defaultValue the default value to use if the property is not 333 * available or a security exception prevents access 334 * @return the boolean representation of the system property value 335 * or the default value if the property is not available or 336 * security does not allow its access 337 */ 338 public static boolean getSystemProperty(String name, Boolean defaultValue) { 339 String result = getSystemProperty(name, defaultValue.toString()); 340 return Boolean.parseBoolean(result); 341 } 342 343 /** 344 * Returns the type name of the given type or null if the type variable is 345 * null 346 */ 347 public static String name(Class type) { 348 return type != null ? type.getName() : null; 349 } 350 351 /** 352 * Returns the type name of the given value 353 */ 354 public static String className(Object value) { 355 return name(value != null ? value.getClass() : null); 356 } 357 358 /** 359 * Returns the canonical type name of the given value 360 */ 361 public static String classCanonicalName(Object value) { 362 if (value != null) { 363 return value.getClass().getCanonicalName(); 364 } else { 365 return null; 366 } 367 } 368 369 /** 370 * Attempts to load the given class name using the thread context class 371 * loader or the class loader used to load this class 372 * 373 * @param name the name of the class to load 374 * @return the class or null if it could not be loaded 375 */ 376 public static Class<?> loadClass(String name) { 377 return loadClass(name, ObjectHelper.class.getClassLoader()); 378 } 379 380 /** 381 * Attempts to load the given class name using the thread context class 382 * loader or the given class loader 383 * 384 * @param name the name of the class to load 385 * @param loader the class loader to use after the thread context class 386 * loader 387 * @return the class or null if it could not be loaded 388 */ 389 public static Class<?> loadClass(String name, ClassLoader loader) { 390 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 391 if (contextClassLoader != null) { 392 try { 393 return contextClassLoader.loadClass(name); 394 } catch (ClassNotFoundException e) { 395 try { 396 return loader.loadClass(name); 397 } catch (ClassNotFoundException e1) { 398 LOG.debug("Could not find class: " + name + ". Reason: " + e); 399 } 400 } 401 } 402 return null; 403 } 404 405 /** 406 * Attempts to load the given resource as a stream using the thread context class 407 * loader or the class loader used to load this class 408 * 409 * @param name the name of the resource to load 410 * @return the stream or null if it could not be loaded 411 */ 412 public static InputStream loadResourceAsStream(String name) { 413 InputStream in = null; 414 415 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 416 if (contextClassLoader != null) { 417 in = contextClassLoader.getResourceAsStream(name); 418 } 419 if (in == null) { 420 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 421 } 422 423 return in; 424 } 425 426 /** 427 * A helper method to invoke a method via reflection and wrap any exceptions 428 * as {@link RuntimeCamelException} instances 429 * 430 * @param method the method to invoke 431 * @param instance the object instance (or null for static methods) 432 * @param parameters the parameters to the method 433 * @return the result of the method invocation 434 */ 435 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 436 try { 437 return method.invoke(instance, parameters); 438 } catch (IllegalAccessException e) { 439 throw new RuntimeCamelException(e); 440 } catch (InvocationTargetException e) { 441 throw new RuntimeCamelException(e.getCause()); 442 } 443 } 444 445 /** 446 * Returns a list of methods which are annotated with the given annotation 447 * 448 * @param type the type to reflect on 449 * @param annotationType the annotation type 450 * @return a list of the methods found 451 */ 452 public static List<Method> findMethodsWithAnnotation(Class<?> type, 453 Class<? extends Annotation> annotationType) { 454 return findMethodsWithAnnotation(type, annotationType, false); 455 } 456 457 /** 458 * Returns a list of methods which are annotated with the given annotation 459 * 460 * @param type the type to reflect on 461 * @param annotationType the annotation type 462 * @param checkMetaAnnotations check for meta annotations 463 * @return a list of the methods found 464 */ 465 public static List<Method> findMethodsWithAnnotation(Class<?> type, 466 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 467 List<Method> answer = new ArrayList<Method>(); 468 do { 469 Method[] methods = type.getDeclaredMethods(); 470 for (Method method : methods) { 471 if (hasAnnotation(method, annotationType, checkMetaAnnotations)) { 472 answer.add(method); 473 } 474 } 475 type = type.getSuperclass(); 476 } while (type != null); 477 return answer; 478 } 479 480 /** 481 * Checks if a Class or Method are annotated with the given annotation 482 * 483 * @param elem the Class or Method to reflect on 484 * @param annotationType the annotation type 485 * @param checkMetaAnnotations check for meta annotations 486 * @return true if annotations is present 487 */ 488 public static boolean hasAnnotation(AnnotatedElement elem, 489 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 490 if (elem.isAnnotationPresent(annotationType)) { 491 return true; 492 } 493 if (checkMetaAnnotations) { 494 for (Annotation a : elem.getAnnotations()) { 495 for (Annotation meta : a.annotationType().getAnnotations()) { 496 if (meta.annotationType().getName().equals(annotationType.getName())) { 497 return true; 498 } 499 } 500 } 501 } 502 return false; 503 } 504 505 /** 506 * Turns the given object arrays into a meaningful string 507 * 508 * @param objects an array of objects or null 509 * @return a meaningful string 510 */ 511 public static String asString(Object[] objects) { 512 if (objects == null) { 513 return "null"; 514 } else { 515 StringBuffer buffer = new StringBuffer("{"); 516 int counter = 0; 517 for (Object object : objects) { 518 if (counter++ > 0) { 519 buffer.append(", "); 520 } 521 String text = (object == null) ? "null" : object.toString(); 522 buffer.append(text); 523 } 524 buffer.append("}"); 525 return buffer.toString(); 526 } 527 } 528 529 /** 530 * Returns true if a class is assignable from another class like the 531 * {@link Class#isAssignableFrom(Class)} method but which also includes 532 * coercion between primitive types to deal with Java 5 primitive type 533 * wrapping 534 */ 535 public static boolean isAssignableFrom(Class a, Class b) { 536 a = convertPrimitiveTypeToWrapperType(a); 537 b = convertPrimitiveTypeToWrapperType(b); 538 return a.isAssignableFrom(b); 539 } 540 541 /** 542 * Converts primitive types such as int to its wrapper type like 543 * {@link Integer} 544 */ 545 public static Class convertPrimitiveTypeToWrapperType(Class type) { 546 Class rc = type; 547 if (type.isPrimitive()) { 548 if (type == int.class) { 549 rc = Integer.class; 550 } else if (type == long.class) { 551 rc = Long.class; 552 } else if (type == double.class) { 553 rc = Double.class; 554 } else if (type == float.class) { 555 rc = Float.class; 556 } else if (type == short.class) { 557 rc = Short.class; 558 } else if (type == byte.class) { 559 rc = Byte.class; 560 // TODO: Why is boolean disabled 561 /* 562 } else if (type == boolean.class) { 563 rc = Boolean.class; 564 */ 565 } 566 } 567 return rc; 568 } 569 570 /** 571 * Helper method to return the default character set name 572 */ 573 public static String getDefaultCharacterSet() { 574 return Charset.defaultCharset().name(); 575 } 576 577 /** 578 * Returns the Java Bean property name of the given method, if it is a setter 579 */ 580 public static String getPropertyName(Method method) { 581 String propertyName = method.getName(); 582 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 583 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 584 } 585 return propertyName; 586 } 587 588 /** 589 * Returns true if the given collection of annotations matches the given type 590 */ 591 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 592 for (Annotation annotation : annotations) { 593 if (type.isInstance(annotation)) { 594 return true; 595 } 596 } 597 return false; 598 } 599 600 /** 601 * Closes the given resource if it is available, logging any closing exceptions to the given log 602 * 603 * @param closeable the object to close 604 * @param name the name of the resource 605 * @param log the log to use when reporting closure warnings 606 */ 607 public static void close(Closeable closeable, String name, Log log) { 608 if (closeable != null) { 609 try { 610 closeable.close(); 611 } catch (IOException e) { 612 if (log != null) { 613 log.warn("Could not close: " + name + ". Reason: " + e, e); 614 } 615 } 616 } 617 } 618 619 /** 620 * Converts the given value to the required type or throw a meaningful exception 621 */ 622 public static <T> T cast(Class<T> toType, Object value) { 623 if (toType == boolean.class) { 624 return (T)cast(Boolean.class, value); 625 } else if (toType.isPrimitive()) { 626 Class newType = convertPrimitiveTypeToWrapperType(toType); 627 if (newType != toType) { 628 return (T)cast(newType, value); 629 } 630 } 631 try { 632 return toType.cast(value); 633 } catch (ClassCastException e) { 634 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 635 + toType.getName() + " due to: " + e, e); 636 } 637 } 638 639 /** 640 * A helper method to create a new instance of a type using the default constructor arguments. 641 */ 642 public static <T> T newInstance(Class<T> type) { 643 try { 644 return type.newInstance(); 645 } catch (InstantiationException e) { 646 throw new RuntimeCamelException(e); 647 } catch (IllegalAccessException e) { 648 throw new RuntimeCamelException(e); 649 } 650 } 651 652 /** 653 * A helper method to create a new instance of a type using the default constructor arguments. 654 */ 655 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 656 try { 657 Object value = actualType.newInstance(); 658 return cast(expectedType, value); 659 } catch (InstantiationException e) { 660 throw new RuntimeCamelException(); 661 } catch (IllegalAccessException e) { 662 throw new RuntimeCamelException(e); 663 } 664 } 665 666 /** 667 * Returns true if the given name is a valid java identifier 668 */ 669 public static boolean isJavaIdentifier(String name) { 670 if (name == null) { 671 return false; 672 } 673 int size = name.length(); 674 if (size < 1) { 675 return false; 676 } 677 if (Character.isJavaIdentifierStart(name.charAt(0))) { 678 for (int i = 1; i < size; i++) { 679 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 680 return false; 681 } 682 } 683 return true; 684 } 685 return false; 686 } 687 688 /** 689 * Returns the type of the given object or null if the value is null 690 */ 691 public static Object type(Object bean) { 692 return bean != null ? bean.getClass() : null; 693 } 694 695 /** 696 * Evaluate the value as a predicate which attempts to convert the value to 697 * a boolean otherwise true is returned if the value is not null 698 */ 699 public static boolean evaluateValuePredicate(Object value) { 700 if (value instanceof Boolean) { 701 Boolean aBoolean = (Boolean)value; 702 return aBoolean.booleanValue(); 703 } else if (value instanceof String) { 704 if ("true".equals(value)) { 705 return true; 706 } else if ("false".equals(value)) { 707 return false; 708 } 709 } 710 return value != null; 711 } 712 713 /** 714 * Wraps the caused exception in a {@link RuntimeCamelException} if its not already such an exception. 715 * 716 * @param e the caused exception 717 * @return the wrapper exception 718 */ 719 public static RuntimeCamelException wrapRuntimeCamelException(Throwable e) { 720 if (e instanceof RuntimeCamelException) { 721 // don't double wrap if already a RuntimeCamelException 722 return (RuntimeCamelException) e; 723 } else { 724 return new RuntimeCamelException(e); 725 } 726 } 727 728 }