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: 64317 $ 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 /** 156 * Asserts whether the value is <b>not</b> <tt>null</tt> 157 * 158 * @param value the value to test 159 * @param name the key that resolved the value 160 * @throws IllegalArgumentException is thrown if assertion fails 161 */ 162 public static void notNull(Object value, String name) { 163 if (value == null) { 164 throw new IllegalArgumentException(name + " must be specified"); 165 } 166 } 167 168 /** 169 * Asserts whether the value is <b>not</b> <tt>null</tt> 170 * 171 * @param value the value to test 172 * @param on additional description to indicate where this problem occured (appended as toString()) 173 * @param name the key that resolved the value 174 * @throws IllegalArgumentException is thrown if assertion fails 175 */ 176 public static void notNull(Object value, String name, Object on) { 177 if (on == null) { 178 notNull(value, name); 179 } else if (value == null) { 180 throw new IllegalArgumentException(name + " must be specified on: " + on); 181 } 182 } 183 184 /** 185 * Asserts whether the string is <b>not</b> empty. 186 * 187 * @param value the string to test 188 * @param name the key that resolved the value 189 * @throws IllegalArgumentException is thrown if assertion fails 190 */ 191 public static void notEmpty(String value, String name) { 192 if (isEmpty(value)) { 193 throw new IllegalArgumentException(name + " must be specified and not empty"); 194 } 195 } 196 197 /** 198 * Asserts whether the string is <b>not</b> empty. 199 * 200 * @param value the string to test 201 * @param on additional description to indicate where this problem occured (appended as toString()) 202 * @param name the key that resolved the value 203 * @throws IllegalArgumentException is thrown if assertion fails 204 */ 205 public static void notEmpty(String value, String name, Object on) { 206 if (on == null) { 207 notNull(value, name); 208 } else if (isEmpty(value)) { 209 throw new IllegalArgumentException(name + " must be specified and not empty on: " + on); 210 } 211 } 212 213 public static String[] splitOnCharacter(String value, String needle, int count) { 214 String rc[] = new String[count]; 215 rc[0] = value; 216 for (int i = 1; i < count; i++) { 217 String v = rc[i - 1]; 218 int p = v.indexOf(needle); 219 if (p < 0) { 220 return rc; 221 } 222 rc[i - 1] = v.substring(0, p); 223 rc[i] = v.substring(p + 1); 224 } 225 return rc; 226 } 227 228 /** 229 * Removes any starting characters on the given text which match the given 230 * character 231 * 232 * @param text the string 233 * @param ch the initial characters to remove 234 * @return either the original string or the new substring 235 */ 236 public static String removeStartingCharacters(String text, char ch) { 237 int idx = 0; 238 while (text.charAt(idx) == ch) { 239 idx++; 240 } 241 if (idx > 0) { 242 return text.substring(idx); 243 } 244 return text; 245 } 246 247 public static String capitalize(String text) { 248 if (text == null) { 249 return null; 250 } 251 int length = text.length(); 252 if (length == 0) { 253 return text; 254 } 255 String answer = text.substring(0, 1).toUpperCase(); 256 if (length > 1) { 257 answer += text.substring(1, length); 258 } 259 return answer; 260 } 261 262 263 /** 264 * Returns true if the collection contains the specified value 265 */ 266 @SuppressWarnings("unchecked") 267 public static boolean contains(Object collectionOrArray, Object value) { 268 if (collectionOrArray instanceof Collection) { 269 Collection collection = (Collection)collectionOrArray; 270 return collection.contains(value); 271 } else if (collectionOrArray instanceof String && value instanceof String) { 272 String str = (String) collectionOrArray; 273 String subStr = (String) value; 274 return str.contains(subStr); 275 } else { 276 Iterator iter = createIterator(collectionOrArray); 277 while (iter.hasNext()) { 278 if (equal(value, iter.next())) { 279 return true; 280 } 281 } 282 } 283 return false; 284 } 285 286 /** 287 * Creates an iterator over the value if the value is a collection, an 288 * Object[] or a primitive type array; otherwise to simplify the caller's 289 * code, we just create a singleton collection iterator over a single value 290 */ 291 @SuppressWarnings("unchecked") 292 public static Iterator createIterator(Object value) { 293 if (value == null) { 294 return Collections.EMPTY_LIST.iterator(); 295 } else if (value instanceof Iterator) { 296 return (Iterator) value; 297 } else if (value instanceof Collection) { 298 Collection collection = (Collection)value; 299 return collection.iterator(); 300 } else if (value.getClass().isArray()) { 301 // TODO we should handle primitive array types? 302 List<Object> list = Arrays.asList((Object[]) value); 303 return list.iterator(); 304 } else if (value instanceof NodeList) { 305 // lets iterate through DOM results after performing XPaths 306 final NodeList nodeList = (NodeList) value; 307 return new Iterator<Node>() { 308 int idx = -1; 309 310 public boolean hasNext() { 311 return ++idx < nodeList.getLength(); 312 } 313 314 public Node next() { 315 return nodeList.item(idx); 316 } 317 318 public void remove() { 319 throw new UnsupportedOperationException(); 320 } 321 }; 322 } else { 323 return Collections.singletonList(value).iterator(); 324 } 325 } 326 327 /** 328 * Returns the predicate matching boolean on a {@link List} result set where 329 * if the first element is a boolean its value is used otherwise this method 330 * returns true if the collection is not empty 331 * 332 * @return <tt>true</tt> if the first element is a boolean and its value is true or 333 * if the list is non empty 334 */ 335 public static boolean matches(List list) { 336 if (!list.isEmpty()) { 337 Object value = list.get(0); 338 if (value instanceof Boolean) { 339 Boolean flag = (Boolean)value; 340 return flag.booleanValue(); 341 } else { 342 // lets assume non-empty results are true 343 return true; 344 } 345 } 346 return false; 347 } 348 349 /** 350 * @deprecated will be removed in Camel 2.0 - use isNotEmpty() instead 351 */ 352 public static boolean isNotNullAndNonEmpty(String text) { 353 return isNotEmpty(text); 354 } 355 356 /** 357 * @deprecated will be removed in Camel 2.0 - use isEmpty() instead 358 */ 359 public static boolean isNullOrBlank(String text) { 360 return isEmpty(text); 361 } 362 363 /** 364 * Tests whether the value is <tt>null</tt> or an empty string. 365 * 366 * @param value the value, if its a String it will be tested for text length as well 367 * @return true if empty 368 */ 369 public static boolean isEmpty(Object value) { 370 return !isNotEmpty(value); 371 } 372 373 /** 374 * Tests whether the value is <b>not</b> <tt>null</tt> or an empty string. 375 * 376 * @param value the value, if its a String it will be tested for text length as well 377 * @return true if <b>not</b> empty 378 */ 379 public static boolean isNotEmpty(Object value) { 380 if (value == null) { 381 return false; 382 } else if (value instanceof String) { 383 String text = (String) value; 384 return text.trim().length() > 0; 385 } else { 386 return true; 387 } 388 } 389 390 /** 391 * A helper method to access a system property, catching any security 392 * exceptions 393 * 394 * @param name the name of the system property required 395 * @param defaultValue the default value to use if the property is not 396 * available or a security exception prevents access 397 * @return the system property value or the default value if the property is 398 * not available or security does not allow its access 399 */ 400 public static String getSystemProperty(String name, String defaultValue) { 401 try { 402 return System.getProperty(name, defaultValue); 403 } catch (Exception e) { 404 if (LOG.isDebugEnabled()) { 405 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, 406 e); 407 } 408 return defaultValue; 409 } 410 } 411 412 /** 413 * A helper method to access a boolean system property, catching any security 414 * exceptions 415 * 416 * @param name the name of the system property required 417 * @param defaultValue the default value to use if the property is not 418 * available or a security exception prevents access 419 * @return the boolean representation of the system property value 420 * or the default value if the property is not available or 421 * security does not allow its access 422 */ 423 public static boolean getSystemProperty(String name, Boolean defaultValue) { 424 String result = getSystemProperty(name, defaultValue.toString()); 425 return Boolean.parseBoolean(result); 426 } 427 428 /** 429 * Returns the type name of the given type or null if the type variable is 430 * null 431 */ 432 public static String name(Class type) { 433 return type != null ? type.getName() : null; 434 } 435 436 /** 437 * Returns the type name of the given value 438 */ 439 public static String className(Object value) { 440 return name(value != null ? value.getClass() : null); 441 } 442 443 /** 444 * Returns the canonical type name of the given value 445 */ 446 public static String classCanonicalName(Object value) { 447 if (value != null) { 448 return value.getClass().getCanonicalName(); 449 } else { 450 return null; 451 } 452 } 453 454 /** 455 * Attempts to load the given class name using the thread context class 456 * loader or the class loader used to load this class 457 * 458 * @param name the name of the class to load 459 * @return the class or null if it could not be loaded 460 */ 461 public static Class<?> loadClass(String name) { 462 return loadClass(name, ObjectHelper.class.getClassLoader()); 463 } 464 465 /** 466 * Attempts to load the given class name using the thread context class 467 * loader or the given class loader 468 * 469 * @param name the name of the class to load 470 * @param loader the class loader to use after the thread context class 471 * loader 472 * @return the class or null if it could not be loaded 473 */ 474 public static Class<?> loadClass(String name, ClassLoader loader) { 475 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 476 if (contextClassLoader != null) { 477 try { 478 return contextClassLoader.loadClass(name); 479 } catch (ClassNotFoundException e) { 480 try { 481 return loader.loadClass(name); 482 } catch (ClassNotFoundException e1) { 483 LOG.debug("Could not find class: " + name + ". Reason: " + e); 484 } 485 } 486 } 487 return null; 488 } 489 490 /** 491 * Attempts to load the given resource as a stream using the thread context class 492 * loader or the class loader used to load this class 493 * 494 * @param name the name of the resource to load 495 * @return the stream or null if it could not be loaded 496 */ 497 public static InputStream loadResourceAsStream(String name) { 498 InputStream in = null; 499 500 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 501 if (contextClassLoader != null) { 502 in = contextClassLoader.getResourceAsStream(name); 503 } 504 if (in == null) { 505 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 506 } 507 508 return in; 509 } 510 511 /** 512 * A helper method to invoke a method via reflection and wrap any exceptions 513 * as {@link RuntimeCamelException} instances 514 * 515 * @param method the method to invoke 516 * @param instance the object instance (or null for static methods) 517 * @param parameters the parameters to the method 518 * @return the result of the method invocation 519 */ 520 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 521 try { 522 return method.invoke(instance, parameters); 523 } catch (IllegalAccessException e) { 524 throw new RuntimeCamelException(e); 525 } catch (InvocationTargetException e) { 526 throw new RuntimeCamelException(e.getCause()); 527 } 528 } 529 530 /** 531 * Returns a list of methods which are annotated with the given annotation 532 * 533 * @param type the type to reflect on 534 * @param annotationType the annotation type 535 * @return a list of the methods found 536 */ 537 public static List<Method> findMethodsWithAnnotation(Class<?> type, 538 Class<? extends Annotation> annotationType) { 539 return findMethodsWithAnnotation(type, annotationType, false); 540 } 541 542 /** 543 * Returns a list of methods which are annotated with the given annotation 544 * 545 * @param type the type to reflect on 546 * @param annotationType the annotation type 547 * @param checkMetaAnnotations check for meta annotations 548 * @return a list of the methods found 549 */ 550 public static List<Method> findMethodsWithAnnotation(Class<?> type, 551 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 552 List<Method> answer = new ArrayList<Method>(); 553 do { 554 Method[] methods = type.getDeclaredMethods(); 555 for (Method method : methods) { 556 if (hasAnnotation(method, annotationType, checkMetaAnnotations)) { 557 answer.add(method); 558 } 559 } 560 type = type.getSuperclass(); 561 } while (type != null); 562 return answer; 563 } 564 565 /** 566 * Checks if a Class or Method are annotated with the given annotation 567 * 568 * @param elem the Class or Method to reflect on 569 * @param annotationType the annotation type 570 * @param checkMetaAnnotations check for meta annotations 571 * @return true if annotations is present 572 */ 573 public static boolean hasAnnotation(AnnotatedElement elem, 574 Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) { 575 if (elem.isAnnotationPresent(annotationType)) { 576 return true; 577 } 578 if (checkMetaAnnotations) { 579 for (Annotation a : elem.getAnnotations()) { 580 for (Annotation meta : a.annotationType().getAnnotations()) { 581 if (meta.annotationType().getName().equals(annotationType.getName())) { 582 return true; 583 } 584 } 585 } 586 } 587 return false; 588 } 589 590 /** 591 * Turns the given object arrays into a meaningful string 592 * 593 * @param objects an array of objects or null 594 * @return a meaningful string 595 */ 596 public static String asString(Object[] objects) { 597 if (objects == null) { 598 return "null"; 599 } else { 600 StringBuffer buffer = new StringBuffer("{"); 601 int counter = 0; 602 for (Object object : objects) { 603 if (counter++ > 0) { 604 buffer.append(", "); 605 } 606 String text = (object == null) ? "null" : object.toString(); 607 buffer.append(text); 608 } 609 buffer.append("}"); 610 return buffer.toString(); 611 } 612 } 613 614 /** 615 * Returns true if a class is assignable from another class like the 616 * {@link Class#isAssignableFrom(Class)} method but which also includes 617 * coercion between primitive types to deal with Java 5 primitive type 618 * wrapping 619 */ 620 public static boolean isAssignableFrom(Class a, Class b) { 621 a = convertPrimitiveTypeToWrapperType(a); 622 b = convertPrimitiveTypeToWrapperType(b); 623 return a.isAssignableFrom(b); 624 } 625 626 /** 627 * Converts primitive types such as int to its wrapper type like 628 * {@link Integer} 629 */ 630 public static Class convertPrimitiveTypeToWrapperType(Class type) { 631 Class rc = type; 632 if (type.isPrimitive()) { 633 if (type == int.class) { 634 rc = Integer.class; 635 } else if (type == long.class) { 636 rc = Long.class; 637 } else if (type == double.class) { 638 rc = Double.class; 639 } else if (type == float.class) { 640 rc = Float.class; 641 } else if (type == short.class) { 642 rc = Short.class; 643 } else if (type == byte.class) { 644 rc = Byte.class; 645 // TODO: Why is boolean disabled 646 /* 647 } else if (type == boolean.class) { 648 rc = Boolean.class; 649 */ 650 } 651 } 652 return rc; 653 } 654 655 /** 656 * Helper method to return the default character set name 657 */ 658 public static String getDefaultCharacterSet() { 659 return Charset.defaultCharset().name(); 660 } 661 662 /** 663 * Returns the Java Bean property name of the given method, if it is a setter 664 */ 665 public static String getPropertyName(Method method) { 666 String propertyName = method.getName(); 667 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 668 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 669 } 670 return propertyName; 671 } 672 673 /** 674 * Returns true if the given collection of annotations matches the given type 675 */ 676 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 677 for (Annotation annotation : annotations) { 678 if (type.isInstance(annotation)) { 679 return true; 680 } 681 } 682 return false; 683 } 684 685 /** 686 * Closes the given resource if it is available, logging any closing exceptions to the given log 687 * 688 * @param closeable the object to close 689 * @param name the name of the resource 690 * @param log the log to use when reporting closure warnings 691 */ 692 public static void close(Closeable closeable, String name, Log log) { 693 if (closeable != null) { 694 try { 695 closeable.close(); 696 } catch (IOException e) { 697 if (log != null) { 698 log.warn("Could not close: " + name + ". Reason: " + e, e); 699 } 700 } 701 } 702 } 703 704 /** 705 * Converts the given value to the required type or throw a meaningful exception 706 */ 707 public static <T> T cast(Class<T> toType, Object value) { 708 if (toType == boolean.class) { 709 return (T)cast(Boolean.class, value); 710 } else if (toType.isPrimitive()) { 711 Class newType = convertPrimitiveTypeToWrapperType(toType); 712 if (newType != toType) { 713 return (T)cast(newType, value); 714 } 715 } 716 try { 717 return toType.cast(value); 718 } catch (ClassCastException e) { 719 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 720 + toType.getName() + " due to: " + e, e); 721 } 722 } 723 724 /** 725 * A helper method to create a new instance of a type using the default constructor arguments. 726 */ 727 public static <T> T newInstance(Class<T> type) { 728 try { 729 return type.newInstance(); 730 } catch (InstantiationException e) { 731 throw new RuntimeCamelException(e); 732 } catch (IllegalAccessException e) { 733 throw new RuntimeCamelException(e); 734 } 735 } 736 737 /** 738 * A helper method to create a new instance of a type using the default constructor arguments. 739 */ 740 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 741 try { 742 Object value = actualType.newInstance(); 743 return cast(expectedType, value); 744 } catch (InstantiationException e) { 745 throw new RuntimeCamelException(); 746 } catch (IllegalAccessException e) { 747 throw new RuntimeCamelException(e); 748 } 749 } 750 751 /** 752 * Returns true if the given name is a valid java identifier 753 */ 754 public static boolean isJavaIdentifier(String name) { 755 if (name == null) { 756 return false; 757 } 758 int size = name.length(); 759 if (size < 1) { 760 return false; 761 } 762 if (Character.isJavaIdentifierStart(name.charAt(0))) { 763 for (int i = 1; i < size; i++) { 764 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 765 return false; 766 } 767 } 768 return true; 769 } 770 return false; 771 } 772 773 /** 774 * Returns the type of the given object or null if the value is null 775 */ 776 public static Object type(Object bean) { 777 return bean != null ? bean.getClass() : null; 778 } 779 780 /** 781 * Evaluate the value as a predicate which attempts to convert the value to 782 * a boolean otherwise true is returned if the value is not null 783 */ 784 public static boolean evaluateValuePredicate(Object value) { 785 if (value instanceof Boolean) { 786 Boolean aBoolean = (Boolean)value; 787 return aBoolean.booleanValue(); 788 } else if (value instanceof String) { 789 if ("true".equals(value)) { 790 return true; 791 } else if ("false".equals(value)) { 792 return false; 793 } 794 } 795 return value != null; 796 } 797 798 /** 799 * Wraps the caused exception in a {@link RuntimeCamelException} if its not already such an exception. 800 * 801 * @param e the caused exception 802 * @return the wrapper exception 803 */ 804 public static RuntimeCamelException wrapRuntimeCamelException(Throwable e) { 805 if (e instanceof RuntimeCamelException) { 806 // don't double wrap if already a RuntimeCamelException 807 return (RuntimeCamelException) e; 808 } else { 809 return new RuntimeCamelException(e); 810 } 811 } 812 813 }