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: 51090 $
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 Iterator) {
243 return (Iterator) value;
244 } else if (value instanceof Collection) {
245 Collection collection = (Collection)value;
246 return collection.iterator();
247 } else if (value.getClass().isArray()) {
248 // TODO we should handle primitive array types?
249 List<Object> list = Arrays.asList((Object[]) value);
250 return list.iterator();
251 } else if (value instanceof NodeList) {
252 // lets iterate through DOM results after performing XPaths
253 final NodeList nodeList = (NodeList) value;
254 return new Iterator<Node>() {
255 int idx = -1;
256
257 public boolean hasNext() {
258 return ++idx < nodeList.getLength();
259 }
260
261 public Node next() {
262 return nodeList.item(idx);
263 }
264
265 public void remove() {
266 throw new UnsupportedOperationException();
267 }
268 };
269 } else {
270 return Collections.singletonList(value).iterator();
271 }
272 }
273
274 /**
275 * Returns the predicate matching boolean on a {@link List} result set where
276 * if the first element is a boolean its value is used otherwise this method
277 * returns true if the collection is not empty
278 *
279 * @return <tt>true</tt> if the first element is a boolean and its value is true or
280 * if the list is non empty
281 */
282 public static boolean matches(List list) {
283 if (!list.isEmpty()) {
284 Object value = list.get(0);
285 if (value instanceof Boolean) {
286 Boolean flag = (Boolean)value;
287 return flag.booleanValue();
288 } else {
289 // lets assume non-empty results are true
290 return true;
291 }
292 }
293 return false;
294 }
295
296 public static boolean isNotNullAndNonEmpty(String text) {
297 return text != null && text.trim().length() > 0;
298 }
299
300 public static boolean isNullOrBlank(String text) {
301 return text == null || text.trim().length() <= 0;
302 }
303
304 /**
305 * A helper method to access a system property, catching any security
306 * exceptions
307 *
308 * @param name the name of the system property required
309 * @param defaultValue the default value to use if the property is not
310 * available or a security exception prevents access
311 * @return the system property value or the default value if the property is
312 * not available or security does not allow its access
313 */
314 public static String getSystemProperty(String name, String defaultValue) {
315 try {
316 return System.getProperty(name, defaultValue);
317 } catch (Exception e) {
318 if (LOG.isDebugEnabled()) {
319 LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e,
320 e);
321 }
322 return defaultValue;
323 }
324 }
325
326 /**
327 * A helper method to access a boolean system property, catching any security
328 * exceptions
329 *
330 * @param name the name of the system property required
331 * @param defaultValue the default value to use if the property is not
332 * available or a security exception prevents access
333 * @return the boolean representation of the system property value
334 * or the default value if the property is not available or
335 * security does not allow its access
336 */
337 public static boolean getSystemProperty(String name, Boolean defaultValue) {
338 String result = getSystemProperty(name, defaultValue.toString());
339 return Boolean.parseBoolean(result);
340 }
341
342 /**
343 * Returns the type name of the given type or null if the type variable is
344 * null
345 */
346 public static String name(Class type) {
347 return type != null ? type.getName() : null;
348 }
349
350 /**
351 * Returns the type name of the given value
352 */
353 public static String className(Object value) {
354 return name(value != null ? value.getClass() : null);
355 }
356
357 /**
358 * Returns the canonical type name of the given value
359 */
360 public static String classCanonicalName(Object value) {
361 if (value != null) {
362 return value.getClass().getCanonicalName();
363 } else {
364 return null;
365 }
366 }
367
368 /**
369 * Attempts to load the given class name using the thread context class
370 * loader or the class loader used to load this class
371 *
372 * @param name the name of the class to load
373 * @return the class or null if it could not be loaded
374 */
375 public static Class<?> loadClass(String name) {
376 return loadClass(name, ObjectHelper.class.getClassLoader());
377 }
378
379 /**
380 * Attempts to load the given class name using the thread context class
381 * loader or the given class loader
382 *
383 * @param name the name of the class to load
384 * @param loader the class loader to use after the thread context class
385 * loader
386 * @return the class or null if it could not be loaded
387 */
388 public static Class<?> loadClass(String name, ClassLoader loader) {
389 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
390 if (contextClassLoader != null) {
391 try {
392 return contextClassLoader.loadClass(name);
393 } catch (ClassNotFoundException e) {
394 try {
395 return loader.loadClass(name);
396 } catch (ClassNotFoundException e1) {
397 LOG.debug("Could not find class: " + name + ". Reason: " + e);
398 }
399 }
400 }
401 return null;
402 }
403
404 /**
405 * Attempts to load the given resource as a stream using the thread context class
406 * loader or the class loader used to load this class
407 *
408 * @param name the name of the resource to load
409 * @return the stream or null if it could not be loaded
410 */
411 public static InputStream loadResourceAsStream(String name) {
412 InputStream in = null;
413
414 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
415 if (contextClassLoader != null) {
416 in = contextClassLoader.getResourceAsStream(name);
417 }
418 if (in == null) {
419 in = ObjectHelper.class.getClassLoader().getResourceAsStream(name);
420 }
421
422 return in;
423 }
424
425 /**
426 * A helper method to invoke a method via reflection and wrap any exceptions
427 * as {@link RuntimeCamelException} instances
428 *
429 * @param method the method to invoke
430 * @param instance the object instance (or null for static methods)
431 * @param parameters the parameters to the method
432 * @return the result of the method invocation
433 */
434 public static Object invokeMethod(Method method, Object instance, Object... parameters) {
435 try {
436 return method.invoke(instance, parameters);
437 } catch (IllegalAccessException e) {
438 throw new RuntimeCamelException(e);
439 } catch (InvocationTargetException e) {
440 throw new RuntimeCamelException(e.getCause());
441 }
442 }
443
444 /**
445 * Returns a list of methods which are annotated with the given annotation
446 *
447 * @param type the type to reflect on
448 * @param annotationType the annotation type
449 * @return a list of the methods found
450 */
451 public static List<Method> findMethodsWithAnnotation(Class<?> type,
452 Class<? extends Annotation> annotationType) {
453 List<Method> answer = new ArrayList<Method>();
454 do {
455 Method[] methods = type.getDeclaredMethods();
456 for (Method method : methods) {
457 if (method.getAnnotation(annotationType) != null) {
458 answer.add(method);
459 }
460 }
461 type = type.getSuperclass();
462 } while (type != null);
463 return answer;
464 }
465
466 /**
467 * Turns the given object arrays into a meaningful string
468 *
469 * @param objects an array of objects or null
470 * @return a meaningful string
471 */
472 public static String asString(Object[] objects) {
473 if (objects == null) {
474 return "null";
475 } else {
476 StringBuffer buffer = new StringBuffer("{");
477 int counter = 0;
478 for (Object object : objects) {
479 if (counter++ > 0) {
480 buffer.append(", ");
481 }
482 String text = (object == null) ? "null" : object.toString();
483 buffer.append(text);
484 }
485 buffer.append("}");
486 return buffer.toString();
487 }
488 }
489
490 /**
491 * Returns true if a class is assignable from another class like the
492 * {@link Class#isAssignableFrom(Class)} method but which also includes
493 * coercion between primitive types to deal with Java 5 primitive type
494 * wrapping
495 */
496 public static boolean isAssignableFrom(Class a, Class b) {
497 a = convertPrimitiveTypeToWrapperType(a);
498 b = convertPrimitiveTypeToWrapperType(b);
499 return a.isAssignableFrom(b);
500 }
501
502 /**
503 * Converts primitive types such as int to its wrapper type like
504 * {@link Integer}
505 */
506 public static Class convertPrimitiveTypeToWrapperType(Class type) {
507 Class rc = type;
508 if (type.isPrimitive()) {
509 if (type == int.class) {
510 rc = Integer.class;
511 } else if (type == long.class) {
512 rc = Long.class;
513 } else if (type == double.class) {
514 rc = Double.class;
515 } else if (type == float.class) {
516 rc = Float.class;
517 } else if (type == short.class) {
518 rc = Short.class;
519 } else if (type == byte.class) {
520 rc = Byte.class;
521 // TODO: Why is boolean disabled
522 /*
523 } else if (type == boolean.class) {
524 rc = Boolean.class;
525 */
526 }
527 }
528 return rc;
529 }
530
531 /**
532 * Helper method to return the default character set name
533 */
534 public static String getDefaultCharacterSet() {
535 return Charset.defaultCharset().name();
536 }
537
538 /**
539 * Returns the Java Bean property name of the given method, if it is a setter
540 */
541 public static String getPropertyName(Method method) {
542 String propertyName = method.getName();
543 if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) {
544 propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4);
545 }
546 return propertyName;
547 }
548
549 /**
550 * Returns true if the given collection of annotations matches the given type
551 */
552 public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
553 for (Annotation annotation : annotations) {
554 if (type.isInstance(annotation)) {
555 return true;
556 }
557 }
558 return false;
559 }
560
561 /**
562 * Closes the given resource if it is available, logging any closing exceptions to the given log
563 *
564 * @param closeable the object to close
565 * @param name the name of the resource
566 * @param log the log to use when reporting closure warnings
567 */
568 public static void close(Closeable closeable, String name, Log log) {
569 if (closeable != null) {
570 try {
571 closeable.close();
572 } catch (IOException e) {
573 if (log != null) {
574 log.warn("Could not close: " + name + ". Reason: " + e, e);
575 }
576 }
577 }
578 }
579
580 /**
581 * Converts the given value to the required type or throw a meaningful exception
582 */
583 public static <T> T cast(Class<T> toType, Object value) {
584 if (toType == boolean.class) {
585 return (T)cast(Boolean.class, value);
586 } else if (toType.isPrimitive()) {
587 Class newType = convertPrimitiveTypeToWrapperType(toType);
588 if (newType != toType) {
589 return (T)cast(newType, value);
590 }
591 }
592 try {
593 return toType.cast(value);
594 } catch (ClassCastException e) {
595 throw new IllegalArgumentException("Failed to convert: " + value + " to type: "
596 + toType.getName() + " due to: " + e, e);
597 }
598 }
599
600 /**
601 * A helper method to create a new instance of a type using the default constructor arguments.
602 */
603 public static <T> T newInstance(Class<T> type) {
604 try {
605 return type.newInstance();
606 } catch (InstantiationException e) {
607 throw new RuntimeCamelException(e.getCause());
608 } catch (IllegalAccessException e) {
609 throw new RuntimeCamelException(e);
610 }
611 }
612
613 /**
614 * A helper method to create a new instance of a type using the default constructor arguments.
615 */
616 public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) {
617 try {
618 Object value = actualType.newInstance();
619 return cast(expectedType, value);
620 } catch (InstantiationException e) {
621 throw new RuntimeCamelException(e.getCause());
622 } catch (IllegalAccessException e) {
623 throw new RuntimeCamelException(e);
624 }
625 }
626
627 /**
628 * Returns true if the given name is a valid java identifier
629 */
630 public static boolean isJavaIdentifier(String name) {
631 if (name == null) {
632 return false;
633 }
634 int size = name.length();
635 if (size < 1) {
636 return false;
637 }
638 if (Character.isJavaIdentifierStart(name.charAt(0))) {
639 for (int i = 1; i < size; i++) {
640 if (!Character.isJavaIdentifierPart(name.charAt(i))) {
641 return false;
642 }
643 }
644 return true;
645 }
646 return false;
647 }
648
649 /**
650 * Returns the type of the given object or null if the value is null
651 */
652 public static Object type(Object bean) {
653 return bean != null ? bean.getClass() : null;
654 }
655
656 /**
657 * Evaluate the value as a predicate which attempts to convert the value to
658 * a boolean otherwise true is returned if the value is not null
659 */
660 public static boolean evaluateValuePredicate(Object value) {
661 if (value instanceof Boolean) {
662 Boolean aBoolean = (Boolean)value;
663 return aBoolean.booleanValue();
664 }
665 return value != null;
666 }
667 }