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 }