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: 673642 $ 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 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 * Returns the type name of the given type or null if the type variable is 326 * null 327 */ 328 public static String name(Class type) { 329 return type != null ? type.getName() : null; 330 } 331 332 /** 333 * Returns the type name of the given value 334 */ 335 public static String className(Object value) { 336 return name(value != null ? value.getClass() : null); 337 } 338 339 /** 340 * Attempts to load the given class name using the thread context class 341 * loader or the class loader used to load this class 342 * 343 * @param name the name of the class to load 344 * @return the class or null if it could not be loaded 345 */ 346 public static Class<?> loadClass(String name) { 347 return loadClass(name, ObjectHelper.class.getClassLoader()); 348 } 349 350 /** 351 * Attempts to load the given class name using the thread context class 352 * loader or the given class loader 353 * 354 * @param name the name of the class to load 355 * @param loader the class loader to use after the thread context class 356 * loader 357 * @return the class or null if it could not be loaded 358 */ 359 public static Class<?> loadClass(String name, ClassLoader loader) { 360 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 361 if (contextClassLoader != null) { 362 try { 363 return contextClassLoader.loadClass(name); 364 } catch (ClassNotFoundException e) { 365 try { 366 return loader.loadClass(name); 367 } catch (ClassNotFoundException e1) { 368 LOG.debug("Could not find class: " + name + ". Reason: " + e); 369 } 370 } 371 } 372 return null; 373 } 374 375 /** 376 * Attempts to load the given resource as a stream using the thread context class 377 * loader or the class loader used to load this class 378 * 379 * @param name the name of the resource to load 380 * @return the stream or null if it could not be loaded 381 */ 382 public static InputStream loadResourceAsStream(String name) { 383 InputStream in = null; 384 385 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 386 if (contextClassLoader != null) { 387 in = contextClassLoader.getResourceAsStream(name); 388 } 389 if (in == null) { 390 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name); 391 } 392 393 return in; 394 } 395 396 /** 397 * A helper method to invoke a method via reflection and wrap any exceptions 398 * as {@link RuntimeCamelException} instances 399 * 400 * @param method the method to invoke 401 * @param instance the object instance (or null for static methods) 402 * @param parameters the parameters to the method 403 * @return the result of the method invocation 404 */ 405 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 406 try { 407 return method.invoke(instance, parameters); 408 } catch (IllegalAccessException e) { 409 throw new RuntimeCamelException(e); 410 } catch (InvocationTargetException e) { 411 throw new RuntimeCamelException(e.getCause()); 412 } 413 } 414 415 /** 416 * Returns a list of methods which are annotated with the given annotation 417 * 418 * @param type the type to reflect on 419 * @param annotationType the annotation type 420 * @return a list of the methods found 421 */ 422 public static List<Method> findMethodsWithAnnotation(Class<?> type, 423 Class<? extends Annotation> annotationType) { 424 List<Method> answer = new ArrayList<Method>(); 425 do { 426 Method[] methods = type.getDeclaredMethods(); 427 for (Method method : methods) { 428 if (method.getAnnotation(annotationType) != null) { 429 answer.add(method); 430 } 431 } 432 type = type.getSuperclass(); 433 } while (type != null); 434 return answer; 435 } 436 437 /** 438 * Turns the given object arrays into a meaningful string 439 * 440 * @param objects an array of objects or null 441 * @return a meaningful string 442 */ 443 public static String asString(Object[] objects) { 444 if (objects == null) { 445 return "null"; 446 } else { 447 StringBuffer buffer = new StringBuffer("{"); 448 int counter = 0; 449 for (Object object : objects) { 450 if (counter++ > 0) { 451 buffer.append(", "); 452 } 453 String text = (object == null) ? "null" : object.toString(); 454 buffer.append(text); 455 } 456 buffer.append("}"); 457 return buffer.toString(); 458 } 459 } 460 461 /** 462 * Returns true if a class is assignable from another class like the 463 * {@link Class#isAssignableFrom(Class)} method but which also includes 464 * coercion between primitive types to deal with Java 5 primitive type 465 * wrapping 466 */ 467 public static boolean isAssignableFrom(Class a, Class b) { 468 a = convertPrimitiveTypeToWrapperType(a); 469 b = convertPrimitiveTypeToWrapperType(b); 470 return a.isAssignableFrom(b); 471 } 472 473 /** 474 * Converts primitive types such as int to its wrapper type like 475 * {@link Integer} 476 */ 477 public static Class convertPrimitiveTypeToWrapperType(Class type) { 478 Class rc = type; 479 if (type.isPrimitive()) { 480 if (type == int.class) { 481 rc = Integer.class; 482 } else if (type == long.class) { 483 rc = Long.class; 484 } else if (type == double.class) { 485 rc = Double.class; 486 } else if (type == float.class) { 487 rc = Float.class; 488 } else if (type == short.class) { 489 rc = Short.class; 490 } else if (type == byte.class) { 491 rc = Byte.class; 492 // TODO: Why is boolean disabled 493 /* 494 } else if (type == boolean.class) { 495 rc = Boolean.class; 496 */ 497 } 498 } 499 return rc; 500 } 501 502 /** 503 * Helper method to return the default character set name 504 */ 505 public static String getDefaultCharacterSet() { 506 return Charset.defaultCharset().name(); 507 } 508 509 /** 510 * Returns the Java Bean property name of the given method, if it is a setter 511 */ 512 public static String getPropertyName(Method method) { 513 String propertyName = method.getName(); 514 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) { 515 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4); 516 } 517 return propertyName; 518 } 519 520 /** 521 * Returns true if the given collection of annotations matches the given type 522 */ 523 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) { 524 for (Annotation annotation : annotations) { 525 if (type.isInstance(annotation)) { 526 return true; 527 } 528 } 529 return false; 530 } 531 532 /** 533 * Closes the given resource if it is available, logging any closing exceptions to the given log 534 * 535 * @param closeable the object to close 536 * @param name the name of the resource 537 * @param log the log to use when reporting closure warnings 538 */ 539 public static void close(Closeable closeable, String name, Log log) { 540 if (closeable != null) { 541 try { 542 closeable.close(); 543 } catch (IOException e) { 544 if (log != null) { 545 log.warn("Could not close: " + name + ". Reason: " + e, e); 546 } 547 } 548 } 549 } 550 551 /** 552 * Converts the given value to the required type or throw a meaningful exception 553 */ 554 public static <T> T cast(Class<T> toType, Object value) { 555 if (toType == boolean.class) { 556 return (T)cast(Boolean.class, value); 557 } else if (toType.isPrimitive()) { 558 Class newType = convertPrimitiveTypeToWrapperType(toType); 559 if (newType != toType) { 560 return (T)cast(newType, value); 561 } 562 } 563 try { 564 return toType.cast(value); 565 } catch (ClassCastException e) { 566 throw new IllegalArgumentException("Failed to convert: " + value + " to type: " 567 + toType.getName() + " due to: " + e, e); 568 } 569 } 570 571 /** 572 * A helper method to create a new instance of a type using the default constructor arguments. 573 */ 574 public static <T> T newInstance(Class<T> type) { 575 try { 576 return type.newInstance(); 577 } catch (InstantiationException e) { 578 throw new RuntimeCamelException(e.getCause()); 579 } catch (IllegalAccessException e) { 580 throw new RuntimeCamelException(e); 581 } 582 } 583 584 /** 585 * A helper method to create a new instance of a type using the default constructor arguments. 586 */ 587 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) { 588 try { 589 Object value = actualType.newInstance(); 590 return cast(expectedType, value); 591 } catch (InstantiationException e) { 592 throw new RuntimeCamelException(e.getCause()); 593 } catch (IllegalAccessException e) { 594 throw new RuntimeCamelException(e); 595 } 596 } 597 598 /** 599 * Returns true if the given name is a valid java identifier 600 */ 601 public static boolean isJavaIdentifier(String name) { 602 if (name == null) { 603 return false; 604 } 605 int size = name.length(); 606 if (size < 1) { 607 return false; 608 } 609 if (Character.isJavaIdentifierStart(name.charAt(0))) { 610 for (int i = 1; i < size; i++) { 611 if (!Character.isJavaIdentifierPart(name.charAt(i))) { 612 return false; 613 } 614 } 615 return true; 616 } 617 return false; 618 } 619 620 /** 621 * Returns the type of the given object or null if the value is null 622 */ 623 public static Object type(Object bean) { 624 return bean != null ? bean.getClass() : null; 625 } 626 627 /** 628 * Evaluate the value as a predicate which attempts to convert the value to 629 * a boolean otherwise true is returned if the value is not null 630 */ 631 public static boolean evaluateValuePredicate(Object value) { 632 if (value instanceof Boolean) { 633 Boolean aBoolean = (Boolean)value; 634 return aBoolean.booleanValue(); 635 } 636 return value != null; 637 } 638 }