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 import java.util.Scanner; 034 035 import org.w3c.dom.Node; 036 import org.w3c.dom.NodeList; 037 038 039 import org.apache.camel.RuntimeCamelException; 040 import org.apache.commons.logging.Log; 041 import org.apache.commons.logging.LogFactory; 042 043 044 /** 045 * A number of useful helper methods for working with Objects 046 * 047 * @version $Revision: 69202 $ 048 */ 049 public final class ObjectHelper { 050 private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class); 051 052 /** 053 * Utility classes should not have a public constructor. 054 */ 055 private ObjectHelper() { 056 } 057 058 /** 059 * @deprecated use the equal method instead. Will be removed in Camel 2.0. 060 * 061 * @see #equal(Object, Object) 062 */ 063 @Deprecated 064 public static boolean equals(Object a, Object b) { 065 return equal(a, b); 066 } 067 068 /** 069 * A helper method for comparing objects for equality while handling nulls 070 */ 071 public static boolean equal(Object a, Object b) { 072 if (a == b) { 073 return true; 074 } 075 076 if (a instanceof byte[] && b instanceof byte[]) { 077 return equalByteArray((byte[]) a, (byte[]) b); 078 } 079 080 return a != null && b != null && a.equals(b); 081 } 082 083 /** 084 * A helper method for comparing byte arrays for equality while handling nulls 085 */ 086 public static boolean equalByteArray(byte[] a, byte[] b) { 087 if (a == b) { 088 return true; 089 } 090 091 // loop and compare each byte 092 if (a != null && b != null && a.length == b.length) { 093 for (int i = 0; i < a.length; i++) { 094 if (a[i] != b[i]) { 095 return false; 096 } 097 } 098 // all bytes are equal 099 return true; 100 } 101 102 return false; 103 } 104 105 /** 106 * Returns true if the given object is equal to any of the expected value 107 */ 108 public static boolean isEqualToAny(Object object, Object... values) { 109 for (Object value : values) { 110 if (equal(object, value)) { 111 return true; 112 } 113 } 114 return false; 115 } 116 117 /** 118 * A helper method for performing an ordered comparison on the objects 119 * handling nulls and objects which do not handle sorting gracefully 120 */ 121 public static int compare(Object a, Object b) { 122 if (a == b) { 123 return 0; 124 } 125 if (a == null) { 126 return -1; 127 } 128 if (b == null) { 129 return 1; 130 } 131 if (a instanceof Comparable) { 132 Comparable comparable = (Comparable)a; 133 return comparable.compareTo(b); 134 } else { 135 int answer = a.getClass().getName().compareTo(b.getClass().getName()); 136 if (answer == 0) { 137 answer = a.hashCode() - b.hashCode(); 138 } 139 return answer; 140 } 141 } 142 143 public static Boolean toBoolean(Object value) { 144 if (value instanceof Boolean) { 145 return (Boolean)value; 146 } 147 if (value instanceof String) { 148 return "true".equalsIgnoreCase(value.toString()) ? Boolean.TRUE : Boolean.FALSE; 149 } 150 if (value instanceof Integer) { 151 return (Integer)value > 0 ? Boolean.TRUE : Boolean.FALSE; 152 } 153 return null; 154 } 155 156 /** 157 * Asserts whether the value is <b>not</b> <tt>null</tt> 158 * 159 * @param value the value to test 160 * @param name the key that resolved the value 161 * @throws IllegalArgumentException is thrown if assertion fails 162 */ 163 public static void notNull(Object value, String name) { 164 if (value == null) { 165 throw new IllegalArgumentException(name + " must be specified"); 166 } 167 } 168 169 /** 170 * Asserts whether the value is <b>not</b> <tt>null</tt> 171 * 172 * @param value the value to test 173 * @param on additional description to indicate where this problem occured (appended as toString()) 174 * @param name the key that resolved the value 175 * @throws IllegalArgumentException is thrown if assertion fails 176 */ 177 public static void notNull(Object value, String name, Object on) { 178 if (on == null) { 179 notNull(value, name); 180 } else if (value == null) { 181 throw new IllegalArgumentException(name + " must be specified on: " + on); 182 } 183 } 184 185 /** 186 * Asserts whether the string is <b>not</b> empty. 187 * 188 * @param value the string to test 189 * @param name the key that resolved the value 190 * @throws IllegalArgumentException is thrown if assertion fails 191 */ 192 public static void notEmpty(String value, String name) { 193 if (isEmpty(value)) { 194 throw new IllegalArgumentException(name + " must be specified and not empty"); 195 } 196 } 197 198 /** 199 * Asserts whether the string is <b>not</b> empty. 200 * 201 * @param value the string to test 202 * @param on additional description to indicate where this problem occured (appended as toString()) 203 * @param name the key that resolved the value 204 * @throws IllegalArgumentException is thrown if assertion fails 205 */ 206 public static void notEmpty(String value, String name, Object on) { 207 if (on == null) { 208 notNull(value, name); 209 } else if (isEmpty(value)) { 210 throw new IllegalArgumentException(name + " must be specified and not empty on: " + on); 211 } 212 } 213 214 public static String[] splitOnCharacter(String value, String needle, int count) { 215 String rc[] = new String[count]; 216 rc[0] = value; 217 for (int i = 1; i < count; i++) { 218 String v = rc[i - 1]; 219 int p = v.indexOf(needle); 220 if (p < 0) { 221 return rc; 222 } 223 rc[i - 1] = v.substring(0, p); 224 rc[i] = v.substring(p + 1); 225 } 226 return rc; 227 } 228 229 /** 230 * Removes any starting characters on the given text which match the given 231 * character 232 * 233 * @param text the string 234 * @param ch the initial characters to remove 235 * @return either the original string or the new substring 236 */ 237 public static String removeStartingCharacters(String text, char ch) { 238 int idx = 0; 239 while (text.charAt(idx) == ch) { 240 idx++; 241 } 242 if (idx > 0) { 243 return text.substring(idx); 244 } 245 return text; 246 } 247 248 public static String capitalize(String text) { 249 if (text == null) { 250 return null; 251 } 252 int length = text.length(); 253 if (length == 0) { 254 return text; 255 } 256 String answer = text.substring(0, 1).toUpperCase(); 257 if (length > 1) { 258 answer += text.substring(1, length); 259 } 260 return answer; 261 } 262 263 264 /** 265 * Returns true if the collection contains the specified value 266 */ 267 @SuppressWarnings("unchecked") 268 public static boolean contains(Object collectionOrArray, Object value) { 269 if (collectionOrArray instanceof Collection) { 270 Collection collection = (Collection)collectionOrArray; 271 return collection.contains(value); 272 } else if (collectionOrArray instanceof String && value instanceof String) { 273 String str = (String) collectionOrArray; 274 String subStr = (String) value; 275 return str.contains(subStr); 276 } else { 277 Iterator iter = createIterator(collectionOrArray); 278 while (iter.hasNext()) { 279 if (equal(value, iter.next())) { 280 return true; 281 } 282 } 283 } 284 return false; 285 } 286 287 /** 288 * Creates an iterator over the value if the value is a collection, an 289 * Object[] or a primitive type array; otherwise to simplify the caller's 290 * code, we just create a singleton collection iterator over a single value 291 */ 292 @SuppressWarnings("unchecked") 293 public static Iterator createIterator(Object value) { 294 if (value == null) { 295 return Collections.EMPTY_LIST.iterator(); 296 } else if (value instanceof Iterator) { 297 return (Iterator) value; 298 } else if (value instanceof Collection) { 299 Collection collection = (Collection)value; 300 return collection.iterator(); 301 } else if (value.getClass().isArray()) { 302 // TODO we should handle primitive array types? 303 List<Object> list = Arrays.asList((Object[]) value); 304 return list.iterator(); 305 } else if (value instanceof NodeList) { 306 // lets iterate through DOM results after performing XPaths 307 final NodeList nodeList = (NodeList) value; 308 return new Iterator<Node>() { 309 int idx = -1; 310 311 public boolean hasNext() { 312 return ++idx < nodeList.getLength(); 313 } 314 315 public Node next() { 316 return nodeList.item(idx); 317 } 318 319 public void remove() { 320 throw new UnsupportedOperationException(); 321 } 322 }; 323 } else if (value instanceof String) { 324 Scanner scanner = new Scanner((String)value); 325 // use comma as delimiter for String values 326 scanner.useDelimiter(","); 327 return scanner; 328 } else { 329 return Collections.singletonList(value).iterator(); 330 } 331 } 332 333 /** 334 * Returns the predicate matching boolean on a {@link List} result set where 335 * if the first element is a boolean its value is used otherwise this method 336 * returns true if the collection is not empty 337 * 338 * @return <tt>true</tt> if the first element is a boolean and its value is true or 339 * if the list is non empty 340 */ 341 public static boolean matches(List list) { 342 if (!list.isEmpty()) { 343 Object value = list.get(0); 344 if (value instanceof Boolean) { 345 Boolean flag = (Boolean)value; 346 return flag.booleanValue(); 347 } else { 348 // lets assume non-empty results are true 349 return true; 350 } 351 } 352 return false; 353 } 354 355 /** 356 * @deprecated will be removed in Camel 2.0 - use isNotEmpty() instead 357 */ 358 public static boolean isNotNullAndNonEmpty(String text) { 359 return isNotEmpty(text); 360 } 361 362 /** 363 * @deprecated will be removed in Camel 2.0 - use isEmpty() instead 364 */ 365 public static boolean isNullOrBlank(String text) { 366 return isEmpty(text); 367 } 368 369 /** 370 * Tests whether the value is <tt>null</tt> or an empty string. 371 * 372 * @param value the value, if its a String it will be tested for text length as well 373 * @return true if empty 374 */ 375 public static boolean isEmpty(Object value) { 376 return !isNotEmpty(value); 377 } 378 379 /** 380 * Tests whether the value is <b>not</b> <tt>null</tt> or an empty string. 381 * 382 * @param value the value, if its a String it will be tested for text length as well 383 * @return true if <b>not</b> empty 384 */ 385 public static boolean isNotEmpty(Object value) { 386 if (value == null) { 387 return false; 388 } else if (value instanceof String) { 389 String text = (String) value; 390 return text.trim().length() > 0; 391 } else { 392 return true; 393 } 394 } 395 396 /** 397 * A helper method to access a system property, catching any security 398 * exceptions 399 * 400 * @param name the name of the system property required 401 * @param defaultValue the default value to use if the property is not 402 * available or a security exception prevents access 403 * @return the system property value or the default value if the property is 404 * not available or security does not allow its access 405 */ 406 public static String getSystemProperty(String name, String defaultValue) { 407 try { 408 return System.getProperty(name, defaultValue); 409 } catch (Exception e) { 410 if (LOG.isDebugEnabled()) { 411 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, 412 e); 413 } 414 return defaultValue; 415 } 416 } 417 418 /** 419 * A helper method to access a boolean system property, catching any security 420 * exceptions 421 * 422 * @param name the name of the system property required 423 * @param defaultValue the default value to use if the property is not 424 * available or a security exception prevents access 425 * @return the boolean representation of the system property value 426 * or the default value if the property is not available or 427 * security does not allow its access 428 */ 429 public static boolean getSystemProperty(String name, Boolean defaultValue) { 430 String result = getSystemProperty(name, defaultValue.toString()); 431 return Boolean.parseBoolean(result); 432 } 433 434 /** 435 * Returns the type name of the given type or null if the type variable is 436 * null 437 */ 438 public static String name(Class type) { 439 return type != null ? type.getName() : null; 440 } 441 442 /** 443 * Returns the type name of the given value 444 */ 445 public static String className(Object value) { 446 return name(value != null ? value.getClass() : null); 447 } 448 449 /** 450 * Returns the canonical type name of the given value 451 */ 452 public static String classCanonicalName(Object value) { 453 if (value != null) { 454 return value.getClass().getCanonicalName(); 455 } else { 456 return null; 457 } 458 } 459 460 /** 461 * Attempts to load the given class name using the thread context class 462 * loader or the class loader used to load this class 463 * 464 * @param name the name of the class to load 465 * @return the class or null if it could not be loaded 466 */ 467 public static Class<?> loadClass(String name) { 468 return loadClass(name, ObjectHelper.class.getClassLoader()); 469 } 470 471 /** 472 * Attempts to load the given class name using the thread context class 473 * loader or the given class loader 474 * 475 * @param name the name of the class to load 476 * @param loader the class loader to use after the thread context class 477 * loader 478 * @return the class or null if it could not be loaded 479 */ 480 public static Class<?> loadClass(String name, ClassLoader loader) { 481 // try context class loader first 482 Class clazz = doLoadClass(name, Thread.currentThread().getContextClassLoader()); 483 if (clazz == null) { 484 // then the provided loader 485 clazz = doLoadClass(name, loader); 486 } 487 if (clazz == null) { 488 // and fallback to the loader the loaded the ObjectHelper class 489 clazz = doLoadClass(name, ObjectHelper.class.getClassLoader()); 490 } 491 492 if (clazz == null) { 493 LOG.warn("Could not find class: " + name); 494 } 495 496 return clazz; 497 } 498 499 /** 500 * Loads the given class with the provided classloader (may be null). 501 * Will ignore any class not found and return null. 502 * 503 * @param name the name of the class to load 504 * @param loader a provided loader (may be null) 505 * @return the class, or null if it could not be loaded 506 */ 507 private static Class<?> doLoadClass(String name, ClassLoader loader) { 508 ObjectHelper.notEmpty(name, "name"); 509 if (loader == null) { 510 return null; 511 } 512 try { 513 return loader.loadClass(name); 514 } catch (ClassNotFoundException e) { 515 if (LOG.isTraceEnabled()) { 516 LOG.trace("Can not load class: " + name + " using classloader: " + loader, e); 517 } 518 519 } 520 return null; 521 } 522 523 /** 524 * Attempts to load the given resource as a stream using the thread context class 525 * loader or the class loader used to load this class 526 * 527 * @param name the name of the resource to load 528 * @return the stream or null if it could not be loaded 529 */ 530 public static InputStream loadResourceAsStream(String name) { 531 InputStream in = null; 532 533 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 534 if (contextClassLoader != null) { 535 in = contextClassLoader.getResourceAsStream(name); 536 } 537 if (in == null) { 538 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 539 } 540 541 return in; 542 } 543 544 /** 545 * A helper method to invoke a method via reflection and wrap any exceptions 546 * as {@link RuntimeCamelException} instances 547 * 548 * @param method the method to invoke 549 * @param instance the object instance (or null for static methods) 550 * @param parameters the parameters to the method 551 * @return the result of the method invocation 552 */ 553 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 554 try { 555 return method.invoke(instance, parameters); 556 } catch (IllegalAccessException e) { 557 throw new RuntimeCamelException(e); 558 } catch (InvocationTargetException e) { 559 throw new RuntimeCamelException(e.getCause()); 560 } 561 } 562 563 /** 564 * Returns a list of methods which are annotated with the given annotation 565 * 566 * @param type the type to reflect on 567 * @param annotationType the annotation type 568 * @return a list of the methods found 569 */ 570 public static List<Method> findMethodsWithAnnotation(Class<?> type, 571 Class<? extends Annotation> annotationType) { 572 return findMethodsWithAnnotation(type, annotationType, false); 573 } 574 575 /** 576 * Returns a list of methods which are annotated with the given annotation 577 * 578 * @param type the type to reflect on 579 * @param annotationType the annotation type 580 * @param checkMetaAnnotations check for meta annotations 581 * @return a list of the methods found 582 */ 583 public static List<Method> findMethodsWithAnnotation(Class<?> type, 584 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 585 List<Method> answer = new ArrayList<Method>(); 586 do { 587 Method[] methods = type.getDeclaredMethods(); 588 for (Method method : methods) { 589 if (hasAnnotation(method, annotationType, checkMetaAnnotations)) { 590 answer.add(method); 591 } 592 } 593 type = type.getSuperclass(); 594 } while (type != null); 595 return answer; 596 } 597 598 /** 599 * Checks if a Class or Method are annotated with the given annotation 600 * 601 * @param elem the Class or Method to reflect on 602 * @param annotationType the annotation type 603 * @param checkMetaAnnotations check for meta annotations 604 * @return true if annotations is present 605 */ 606 public static boolean hasAnnotation(AnnotatedElement elem, 607 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 608 if (elem.isAnnotationPresent(annotationType)) { 609 return true; 610 } 611 if (checkMetaAnnotations) { 612 for (Annotation a : elem.getAnnotations()) { 613 for (Annotation meta : a.annotationType().getAnnotations()) { 614 if (meta.annotationType().getName().equals(annotationType.getName())) { 615 return true; 616 } 617 } 618 } 619 } 620 return false; 621 } 622 623 /** 624 * Turns the given object arrays into a meaningful string 625 * 626 * @param objects an array of objects or null 627 * @return a meaningful string 628 */ 629 public static String asString(Object[] objects) { 630 if (objects == null) { 631 return "null"; 632 } else { 633 StringBuffer buffer = new StringBuffer("{"); 634 int counter = 0; 635 for (Object object : objects) { 636 if (counter++ > 0) { 637 buffer.append(", "); 638 } 639 String text = (object == null) ? "null" : object.toString(); 640 buffer.append(text); 641 } 642 buffer.append("}"); 643 return buffer.toString(); 644 } 645 } 646 647 /** 648 * Returns true if a class is assignable from another class like the 649 * {@link Class#isAssignableFrom(Class)} method but which also includes 650 * coercion between primitive types to deal with Java 5 primitive type 651 * wrapping 652 */ 653 public static boolean isAssignableFrom(Class a, Class b) { 654 a = convertPrimitiveTypeToWrapperType(a); 655 b = convertPrimitiveTypeToWrapperType(b); 656 return a.isAssignableFrom(b); 657 } 658 659 /** 660 * Converts primitive types such as int to its wrapper type like 661 * {@link Integer} 662 */ 663 public static Class convertPrimitiveTypeToWrapperType(Class type) { 664 Class rc = type; 665 if (type.isPrimitive()) { 666 if (type == int.class) { 667 rc = Integer.class; 668 } else if (type == long.class) { 669 rc = Long.class; 670 } else if (type == double.class) { 671 rc = Double.class; 672 } else if (type == float.class) { 673 rc = Float.class; 674 } else if (type == short.class) { 675 rc = Short.class; 676 } else if (type == byte.class) { 677 rc = Byte.class; 678 // TODO: Why is boolean disabled 679 /* 680 } else if (type == boolean.class) { 681 rc = Boolean.class; 682 */ 683 } 684 } 685 return rc; 686 } 687 688 /** 689 * Helper method to return the default character set name 690 */ 691 public static String getDefaultCharacterSet() { 692 return Charset.defaultCharset().name(); 693 } 694 695 /** 696 * Returns the Java Bean property name of the given method, if it is a setter 697 */ 698 public static String getPropertyName(Method method) { 699 String propertyName = method.getName(); 700 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 701 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 702 } 703 return propertyName; 704 } 705 706 /** 707 * Returns true if the given collection of annotations matches the given type 708 */ 709 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 710 for (Annotation annotation : annotations) { 711 if (type.isInstance(annotation)) { 712 return true; 713 } 714 } 715 return false; 716 } 717 718 /** 719 * Closes the given resource if it is available, logging any closing exceptions to the given log 720 * 721 * @param closeable the object to close 722 * @param name the name of the resource 723 * @param log the log to use when reporting closure warnings 724 */ 725 public static void close(Closeable closeable, String name, Log log) { 726 if (closeable != null) { 727 try { 728 closeable.close(); 729 } catch (IOException e) { 730 if (log != null) { 731 log.warn("Could not close: " + name + ". Reason: " + e, e); 732 } 733 } 734 } 735 } 736 737 /** 738 * Converts the given value to the required type or throw a meaningful exception 739 */ 740 public static <T> T cast(Class<T> toType, Object value) { 741 if (toType == boolean.class) { 742 return (T)cast(Boolean.class, value); 743 } else if (toType.isPrimitive()) { 744 Class newType = convertPrimitiveTypeToWrapperType(toType); 745 if (newType != toType) { 746 return (T)cast(newType, value); 747 } 748 } 749 try { 750 return toType.cast(value); 751 } catch (ClassCastException e) { 752 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 753 + toType.getName() + " due to: " + e, e); 754 } 755 } 756 757 /** 758 * A helper method to create a new instance of a type using the default constructor arguments. 759 */ 760 public static <T> T newInstance(Class<T> type) { 761 try { 762 return type.newInstance(); 763 } catch (InstantiationException e) { 764 throw new RuntimeCamelException(e); 765 } catch (IllegalAccessException e) { 766 throw new RuntimeCamelException(e); 767 } 768 } 769 770 /** 771 * A helper method to create a new instance of a type using the default constructor arguments. 772 */ 773 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 774 try { 775 Object value = actualType.newInstance(); 776 return cast(expectedType, value); 777 } catch (InstantiationException e) { 778 throw new RuntimeCamelException(); 779 } catch (IllegalAccessException e) { 780 throw new RuntimeCamelException(e); 781 } 782 } 783 784 /** 785 * Returns true if the given name is a valid java identifier 786 */ 787 public static boolean isJavaIdentifier(String name) { 788 if (name == null) { 789 return false; 790 } 791 int size = name.length(); 792 if (size < 1) { 793 return false; 794 } 795 if (Character.isJavaIdentifierStart(name.charAt(0))) { 796 for (int i = 1; i < size; i++) { 797 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 798 return false; 799 } 800 } 801 return true; 802 } 803 return false; 804 } 805 806 /** 807 * Returns the type of the given object or null if the value is null 808 */ 809 public static Object type(Object bean) { 810 return bean != null ? bean.getClass() : null; 811 } 812 813 /** 814 * Evaluate the value as a predicate which attempts to convert the value to 815 * a boolean otherwise true is returned if the value is not null 816 */ 817 public static boolean evaluateValuePredicate(Object value) { 818 if (value instanceof Boolean) { 819 Boolean aBoolean = (Boolean)value; 820 return aBoolean.booleanValue(); 821 } else if (value instanceof String) { 822 if ("true".equals(value)) { 823 return true; 824 } else if ("false".equals(value)) { 825 return false; 826 } 827 } 828 return value != null; 829 } 830 831 /** 832 * Wraps the caused exception in a {@link RuntimeCamelException} if its not already such an exception. 833 * 834 * @param e the caused exception 835 * @return the wrapper exception 836 */ 837 public static RuntimeCamelException wrapRuntimeCamelException(Throwable e) { 838 if (e instanceof RuntimeCamelException) { 839 // don't double wrap if already a RuntimeCamelException 840 return (RuntimeCamelException) e; 841 } else { 842 return new RuntimeCamelException(e); 843 } 844 } 845 846 }