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 */
017package org.apache.camel.util;
018
019import java.io.IOException;
020import java.io.InputStream;
021import java.lang.annotation.Annotation;
022import java.lang.reflect.AnnotatedElement;
023import java.lang.reflect.Constructor;
024import java.lang.reflect.Field;
025import java.lang.reflect.Method;
026import java.net.URL;
027import java.nio.charset.Charset;
028import java.util.ArrayList;
029import java.util.Arrays;
030import java.util.Collection;
031import java.util.Collections;
032import java.util.Enumeration;
033import java.util.Iterator;
034import java.util.List;
035import java.util.Locale;
036import java.util.Map;
037import java.util.Objects;
038import java.util.Optional;
039import java.util.function.Consumer;
040import java.util.function.Supplier;
041
042import org.w3c.dom.Node;
043import org.w3c.dom.NodeList;
044
045import org.slf4j.Logger;
046import org.slf4j.LoggerFactory;
047
048/**
049 * A number of useful helper methods for working with Objects
050 */
051public final class ObjectHelper {
052
053    private static final Logger LOG = LoggerFactory.getLogger(ObjectHelper.class);
054
055    private static final Float FLOAT_NAN = Float.NaN;
056    private static final Double DOUBLE_NAN = Double.NaN;
057
058    /**
059     * Utility classes should not have a public constructor.
060     */
061    private ObjectHelper() {
062    }
063
064    /**
065     * A helper method for comparing objects for equality while handling nulls
066     */
067    public static boolean equal(Object a, Object b) {
068        return equal(a, b, false);
069    }
070
071    /**
072     * A helper method for comparing objects for equality while handling case insensitivity
073     */
074    public static boolean equalIgnoreCase(Object a, Object b) {
075        return equal(a, b, true);
076    }
077
078    /**
079     * A helper method for comparing objects for equality while handling nulls
080     */
081    public static boolean equal(final Object a, final Object b, final boolean ignoreCase) {
082        if (a == b) {
083            return true;
084        }
085
086        if (a == null || b == null) {
087            return false;
088        }
089
090        if (ignoreCase) {
091            if (a instanceof String && b instanceof String) {
092                return ((String) a).equalsIgnoreCase((String) b);
093            }
094        }
095
096        if (a.getClass().isArray() && b.getClass().isArray()) {
097            // uses array based equals
098            return Objects.deepEquals(a, b);
099        } else {
100            // use regular equals
101            return a.equals(b);
102        }
103    }
104
105    /**
106     * A helper method for comparing byte arrays for equality while handling
107     * nulls
108     */
109    public static boolean equalByteArray(byte[] a, byte[] b) {
110        return Arrays.equals(a, b);
111    }
112
113    /**
114     * Returns true if the given object is equal to any of the expected value
115     */
116    public static boolean isEqualToAny(Object object, Object... values) {
117        for (Object value : values) {
118            if (equal(object, value)) {
119                return true;
120            }
121        }
122        return false;
123    }
124
125    public static Boolean toBoolean(Object value) {
126        if (value instanceof Boolean) {
127            return (Boolean) value;
128        }
129        if (value instanceof String) {
130            return Boolean.valueOf((String) value);
131        }
132        if (value instanceof Integer) {
133            return (Integer) value > 0 ? Boolean.TRUE : Boolean.FALSE;
134        }
135        return null;
136    }
137
138    /**
139     * Asserts whether the value is <b>not</b> <tt>null</tt>
140     *
141     * @param value  the value to test
142     * @param name   the key that resolved the value
143     * @return the passed {@code value} as is
144     * @throws IllegalArgumentException is thrown if assertion fails
145     */
146    public static <T> T notNull(T value, String name) {
147        if (value == null) {
148            throw new IllegalArgumentException(name + " must be specified");
149        }
150
151        return value;
152    }
153
154    /**
155     * Asserts whether the value is <b>not</b> <tt>null</tt>
156     *
157     * @param value  the value to test
158     * @param on     additional description to indicate where this problem occurred (appended as toString())
159     * @param name   the key that resolved the value
160     * @return the passed {@code value} as is
161     * @throws IllegalArgumentException is thrown if assertion fails
162     */
163    public static <T> T notNull(T value, String name, Object on) {
164        if (on == null) {
165            notNull(value, name);
166        } else if (value == null) {
167            throw new IllegalArgumentException(name + " must be specified on: " + on);
168        }
169
170        return value;
171    }
172
173    /**
174     * Tests whether the value is <tt>null</tt> or an empty string.
175     *
176     * @param value  the value, if its a String it will be tested for text length as well
177     * @return true if empty
178     */
179    public static boolean isEmpty(Object value) {
180        return !isNotEmpty(value);
181    }
182
183    /**
184     * Tests whether the value is <b>not</b> <tt>null</tt>, an empty string or an empty collection/map.
185     *
186     * @param value  the value, if its a String it will be tested for text length as well
187     * @return true if <b>not</b> empty
188     */
189    public static boolean isNotEmpty(Object value) {
190        if (value == null) {
191            return false;
192        } else if (value instanceof String) {
193            String text = (String) value;
194            return text.trim().length() > 0;
195        } else if (value instanceof Collection) {
196            return !((Collection<?>) value).isEmpty();
197        } else if (value instanceof Map) {
198            return !((Map<?, ?>) value).isEmpty();
199        } else {
200            return true;
201        }
202    }
203
204
205    /**
206     * Returns the first non null object <tt>null</tt>.
207     *
208     * @param values the values
209     * @return an Optional
210     */
211    public static Optional<Object> firstNotNull(Object... values) {
212        for (Object value : values) {
213            if (value != null) {
214                return Optional.of(value);
215            }
216        }
217
218        return Optional.empty();
219    }
220
221    /**
222     * Tests whether the value is  <tt>null</tt>, an empty string, an empty collection or a map
223     *
224     * @param value  the value, if its a String it will be tested for text length as well
225     * @param supplier  the supplier, the supplier to be used to get a value if value is null
226     */
227    public static <T> T supplyIfEmpty(T value, Supplier<T> supplier) {
228        org.apache.camel.util.ObjectHelper.notNull(supplier, "Supplier");
229        if (isNotEmpty(value)) {
230            return value;
231        }
232
233        return supplier.get();
234    }
235
236    /**
237     * Tests whether the value is <b>not</b> <tt>null</tt>, an empty string, an empty collection or a map
238     *
239     * @param value  the value, if its a String it will be tested for text length as well
240     * @param consumer  the consumer, the operation to be executed against value if not empty
241     */
242    public static <T> void ifNotEmpty(T value, Consumer<T> consumer) {
243        if (isNotEmpty(value)) {
244            consumer.accept(value);
245        }
246    }
247
248    /**
249     * Returns the predicate matching boolean on a {@link List} result set where
250     * if the first element is a boolean its value is used otherwise this method
251     * returns true if the collection is not empty
252     *
253     * @return <tt>true</tt> if the first element is a boolean and its value
254     *         is true or if the list is non empty
255     */
256    public static boolean matches(List<?> list) {
257        if (!list.isEmpty()) {
258            Object value = list.get(0);
259            if (value instanceof Boolean) {
260                return (Boolean) value;
261            } else {
262                // lets assume non-empty results are true
263                return true;
264            }
265        }
266        return false;
267    }
268
269    /**
270     * A helper method to access a system property, catching any security exceptions
271     *
272     * @param name         the name of the system property required
273     * @param defaultValue the default value to use if the property is not
274     *                     available or a security exception prevents access
275     * @return the system property value or the default value if the property is
276     *         not available or security does not allow its access
277     */
278    public static String getSystemProperty(String name, String defaultValue) {
279        try {
280            return System.getProperty(name, defaultValue);
281        } catch (Exception e) {
282            if (LOG.isDebugEnabled()) {
283                LOG.debug("Caught security exception accessing system property: " + name + ". Will use default value: " + defaultValue, e);
284            }
285            return defaultValue;
286        }
287    }
288
289    /**
290     * A helper method to access a boolean system property, catching any
291     * security exceptions
292     *
293     * @param name         the name of the system property required
294     * @param defaultValue the default value to use if the property is not
295     *                     available or a security exception prevents access
296     * @return the boolean representation of the system property value or the
297     *         default value if the property is not available or security does
298     *         not allow its access
299     */
300    public static boolean getSystemProperty(String name, Boolean defaultValue) {
301        String result = getSystemProperty(name, defaultValue.toString());
302        return Boolean.parseBoolean(result);
303    }
304
305    /**
306     * Returns the type name of the given type or null if the type variable is
307     * null
308     */
309    public static String name(Class<?> type) {
310        return type != null ? type.getName() : null;
311    }
312
313    /**
314     * Returns the type name of the given value
315     */
316    public static String className(Object value) {
317        return name(value != null ? value.getClass() : null);
318    }
319
320    /**
321     * Returns the canonical type name of the given value
322     */
323    public static String classCanonicalName(Object value) {
324        if (value != null) {
325            return value.getClass().getCanonicalName();
326        } else {
327            return null;
328        }
329    }
330
331    /**
332     * Attempts to load the given class name using the thread context class
333     * loader or the class loader used to load this class
334     *
335     * @param name the name of the class to load
336     * @return the class or <tt>null</tt> if it could not be loaded
337     */
338    public static Class<?> loadClass(String name) {
339        return loadClass(name, ObjectHelper.class.getClassLoader());
340    }
341
342    /**
343     * Attempts to load the given class name using the thread context class
344     * loader or the given class loader
345     *
346     * @param name the name of the class to load
347     * @param loader the class loader to use after the thread context class loader
348     * @return the class or <tt>null</tt> if it could not be loaded
349     */
350    public static Class<?> loadClass(String name, ClassLoader loader) {
351        return loadClass(name, loader, false);
352    }
353
354    /**
355     * Attempts to load the given class name using the thread context class
356     * loader or the given class loader
357     *
358     * @param name the name of the class to load
359     * @param loader the class loader to use after the thread context class loader
360     * @param needToWarn when <tt>true</tt> logs a warning when a class with the given name could not be loaded
361     * @return the class or <tt>null</tt> if it could not be loaded
362     */
363    public static Class<?> loadClass(String name, ClassLoader loader, boolean needToWarn) {
364        // must clean the name so its pure java name, eg removing \n or whatever people can do in the Spring XML
365        name = StringHelper.normalizeClassName(name);
366        if (org.apache.camel.util.ObjectHelper.isEmpty(name)) {
367            return null;
368        }
369
370        // Try simple type first
371        Class<?> clazz = loadSimpleType(name);
372        if (clazz == null) {
373            // try context class loader
374            clazz = doLoadClass(name, Thread.currentThread().getContextClassLoader());
375        }
376        if (clazz == null) {
377            // then the provided loader
378            clazz = doLoadClass(name, loader);
379        }
380        if (clazz == null) {
381            // and fallback to the loader the loaded the ObjectHelper class
382            clazz = doLoadClass(name, ObjectHelper.class.getClassLoader());
383        }
384
385        if (clazz == null) {
386            if (needToWarn) {
387                LOG.warn("Cannot find class: {}", name);
388            } else {
389                LOG.debug("Cannot find class: {}", name);
390            }
391        }
392
393        return clazz;
394    }
395
396
397    /**
398     * Load a simple type
399     *
400     * @param name the name of the class to load
401     * @return the class or <tt>null</tt> if it could not be loaded
402     */
403    //CHECKSTYLE:OFF
404    public static Class<?> loadSimpleType(String name) {
405        // special for byte[] or Object[] as its common to use
406        if ("java.lang.byte[]".equals(name) || "byte[]".equals(name)) {
407            return byte[].class;
408        } else if ("java.lang.Byte[]".equals(name) || "Byte[]".equals(name)) {
409            return Byte[].class;
410        } else if ("java.lang.Object[]".equals(name) || "Object[]".equals(name)) {
411            return Object[].class;
412        } else if ("java.lang.String[]".equals(name) || "String[]".equals(name)) {
413            return String[].class;
414            // and these is common as well
415        } else if ("java.lang.String".equals(name) || "String".equals(name)) {
416            return String.class;
417        } else if ("java.lang.Boolean".equals(name) || "Boolean".equals(name)) {
418            return Boolean.class;
419        } else if ("boolean".equals(name)) {
420            return boolean.class;
421        } else if ("java.lang.Integer".equals(name) || "Integer".equals(name)) {
422            return Integer.class;
423        } else if ("int".equals(name)) {
424            return int.class;
425        } else if ("java.lang.Long".equals(name) || "Long".equals(name)) {
426            return Long.class;
427        } else if ("long".equals(name)) {
428            return long.class;
429        } else if ("java.lang.Short".equals(name) || "Short".equals(name)) {
430            return Short.class;
431        } else if ("short".equals(name)) {
432            return short.class;
433        } else if ("java.lang.Byte".equals(name) || "Byte".equals(name)) {
434            return Byte.class;
435        } else if ("byte".equals(name)) {
436            return byte.class;
437        } else if ("java.lang.Float".equals(name) || "Float".equals(name)) {
438            return Float.class;
439        } else if ("float".equals(name)) {
440            return float.class;
441        } else if ("java.lang.Double".equals(name) || "Double".equals(name)) {
442            return Double.class;
443        } else if ("double".equals(name)) {
444            return double.class;
445        } else if ("java.lang.Character".equals(name) || "Character".equals(name)) {
446            return Character.class;
447        } else if ("char".equals(name)) {
448            return char.class;
449        }
450        return null;
451    }
452    //CHECKSTYLE:ON
453
454    /**
455     * Loads the given class with the provided classloader (may be null).
456     * Will ignore any class not found and return null.
457     *
458     * @param name    the name of the class to load
459     * @param loader  a provided loader (may be null)
460     * @return the class, or null if it could not be loaded
461     */
462    private static Class<?> doLoadClass(String name, ClassLoader loader) {
463        StringHelper.notEmpty(name, "name");
464        if (loader == null) {
465            return null;
466        }
467
468        try {
469            LOG.trace("Loading class: {} using classloader: {}", name, loader);
470            return loader.loadClass(name);
471        } catch (ClassNotFoundException e) {
472            if (LOG.isTraceEnabled()) {
473                LOG.trace("Cannot load class: " + name + " using classloader: " + loader, e);
474            }
475        }
476
477        return null;
478    }
479
480    /**
481     * Attempts to load the given resource as a stream using the thread context
482     * class loader or the class loader used to load this class
483     *
484     * @param name the name of the resource to load
485     * @return the stream or null if it could not be loaded
486     */
487    public static InputStream loadResourceAsStream(String name) {
488        return loadResourceAsStream(name, null);
489    }
490
491    /**
492     * Attempts to load the given resource as a stream using 
493     * first the given class loader, then the thread context
494     * class loader and finally the class loader used to load this class
495     *
496     * @param name the name of the resource to load
497     * @param loader optional classloader to attempt first
498     * @return the stream or null if it could not be loaded
499     */
500    public static InputStream loadResourceAsStream(String name, ClassLoader loader) {
501        try {
502            URL res = loadResourceAsURL(name);
503            return res != null ? res.openStream() : null;
504        } catch (IOException e) {
505            return null;
506        }
507    }
508
509    /**
510     * Attempts to load the given resource as a stream using the thread context
511     * class loader or the class loader used to load this class
512     *
513     * @param name the name of the resource to load
514     * @return the stream or null if it could not be loaded
515     */
516    public static URL loadResourceAsURL(String name) {
517        return loadResourceAsURL(name, null);
518    }
519
520    /**
521     * Attempts to load the given resource as a stream using the thread context
522     * class loader or the class loader used to load this class
523     *
524     * @param name the name of the resource to load
525     * @param loader optional classloader to attempt first
526     * @return the stream or null if it could not be loaded
527     */
528    public static URL loadResourceAsURL(String name, ClassLoader loader) {
529
530        URL url = null;
531        String resolvedName = resolveUriPath(name);
532
533        // #1 First, try the given class loader
534
535        if (loader != null) {
536            url = loader.getResource(resolvedName);
537            if (url != null) {
538                return url;
539            }
540        }
541
542        // #2 Next, is the TCCL
543
544        ClassLoader tccl = Thread.currentThread().getContextClassLoader();
545        if (tccl != null) {
546
547            url = tccl.getResource(resolvedName);
548            if (url != null) {
549                return url;
550            }
551
552            // #3 The TCCL may be able to see camel-core, but not META-INF resources
553
554            try {
555
556                Class<?> clazz = tccl.loadClass("org.apache.camel.impl.DefaultCamelContext");
557                url = clazz.getClassLoader().getResource(resolvedName);
558                if (url != null) {
559                    return url;
560                }
561
562            } catch (ClassNotFoundException e) {
563                // ignore
564            }
565        }
566
567        // #4 Last, for the unlikely case that stuff can be loaded from camel-util
568
569        url = ObjectHelper.class.getClassLoader().getResource(resolvedName);
570        if (url != null) {
571            return url;
572        }
573
574        url = ObjectHelper.class.getResource(resolvedName);
575        return url;
576    }
577
578    /**
579     * Attempts to load the given resources from the given package name using the thread context
580     * class loader or the class loader used to load this class
581     *
582     * @param uri the name of the package to load its resources
583     * @return the URLs for the resources or null if it could not be loaded
584     */
585    public static Enumeration<URL> loadResourcesAsURL(String uri) {
586        return loadResourcesAsURL(uri, null);
587    }
588
589    /**
590     * Attempts to load the given resources from the given package name using the thread context
591     * class loader or the class loader used to load this class
592     *
593     * @param uri the name of the package to load its resources
594     * @param loader optional classloader to attempt first
595     * @return the URLs for the resources or null if it could not be loaded
596     */
597    public static Enumeration<URL> loadResourcesAsURL(String uri, ClassLoader loader) {
598
599        Enumeration<URL> res = null;
600
601        // #1 First, try the given class loader
602
603        if (loader != null) {
604            try {
605                res = loader.getResources(uri);
606                if (res != null) {
607                    return res;
608                }
609            } catch (IOException e) {
610                // ignore
611            }
612        }
613
614        // #2 Next, is the TCCL
615
616        ClassLoader tccl = Thread.currentThread().getContextClassLoader();
617        if (tccl != null) {
618
619            try {
620                res = tccl.getResources(uri);
621                if (res != null) {
622                    return res;
623                }
624            } catch (IOException e1) {
625                // ignore
626            }
627
628            // #3 The TCCL may be able to see camel-core, but not META-INF resources
629
630            try {
631
632                Class<?> clazz = tccl.loadClass("org.apache.camel.impl.DefaultCamelContext");
633                res = clazz.getClassLoader().getResources(uri);
634                if (res != null) {
635                    return res;
636                }
637
638            } catch (ClassNotFoundException | IOException e) {
639                // ignore
640            }
641        }
642
643        // #4 Last, for the unlikely case that stuff can be loaded from camel-util
644
645        try {
646            res = ObjectHelper.class.getClassLoader().getResources(uri);
647        } catch (IOException e) {
648            // ignore
649        }
650
651        return res;
652    }
653
654    /**
655     * Helper operation used to remove relative path notation from 
656     * resources.  Most critical for resources on the Classpath
657     * as resource loaders will not resolve the relative paths correctly.
658     *
659     * @param name the name of the resource to load
660     * @return the modified or unmodified string if there were no changes
661     */
662    private static String resolveUriPath(String name) {
663        // compact the path and use / as separator as that's used for loading resources on the classpath
664        return FileUtil.compactPath(name, '/');
665    }
666
667    /**
668     * Tests whether the target method overrides the source method.
669     * <p/>
670     * Tests whether they have the same name, return type, and parameter list.
671     *
672     * @param source  the source method
673     * @param target  the target method
674     * @return <tt>true</tt> if it override, <tt>false</tt> otherwise
675     */
676    public static boolean isOverridingMethod(Method source, Method target) {
677        return isOverridingMethod(source, target, true);
678    }
679
680    /**
681     * Tests whether the target method overrides the source method.
682     * <p/>
683     * Tests whether they have the same name, return type, and parameter list.
684     *
685     * @param source  the source method
686     * @param target  the target method
687     * @param exact   <tt>true</tt> if the override must be exact same types, <tt>false</tt> if the types should be assignable
688     * @return <tt>true</tt> if it override, <tt>false</tt> otherwise
689     */
690    public static boolean isOverridingMethod(Method source, Method target, boolean exact) {
691        return isOverridingMethod(target.getDeclaringClass(), source, target, exact);
692    }
693
694    /**
695     * Tests whether the target method overrides the source method from the
696     * inheriting class.
697     * <p/>
698     * Tests whether they have the same name, return type, and parameter list.
699     *
700     * @param inheritingClass the class inheriting the target method overriding
701     *            the source method
702     * @param source the source method
703     * @param target the target method
704     * @param exact <tt>true</tt> if the override must be exact same types,
705     *            <tt>false</tt> if the types should be assignable
706     * @return <tt>true</tt> if it override, <tt>false</tt> otherwise
707     */
708    public static boolean isOverridingMethod(Class<?> inheritingClass, Method source, Method target, boolean exact) {
709
710        if (source.equals(target)) {
711            return true;
712        } else if (target.getDeclaringClass().isAssignableFrom(source.getDeclaringClass())) {
713            return false;
714        } else if (!source.getDeclaringClass().isAssignableFrom(inheritingClass) || !target.getDeclaringClass().isAssignableFrom(inheritingClass)) {
715            return false;
716        }
717
718        if (!source.getName().equals(target.getName())) {
719            return false;
720        }
721
722        if (exact) {
723            if (!source.getReturnType().equals(target.getReturnType())) {
724                return false;
725            }
726        } else {
727            if (!source.getReturnType().isAssignableFrom(target.getReturnType())) {
728                boolean b1 = source.isBridge();
729                boolean b2 = target.isBridge();
730                // must not be bridge methods
731                if (!b1 && !b2) {
732                    return false;
733                }
734            }
735        }
736
737        // must have same number of parameter types
738        if (source.getParameterCount() != target.getParameterCount()) {
739            return false;
740        }
741
742        Class<?>[] sourceTypes = source.getParameterTypes();
743        Class<?>[] targetTypes = target.getParameterTypes();
744        // test if parameter types is the same as well
745        for (int i = 0; i < source.getParameterCount(); i++) {
746            if (exact) {
747                if (!(sourceTypes[i].equals(targetTypes[i]))) {
748                    return false;
749                }
750            } else {
751                if (!(sourceTypes[i].isAssignableFrom(targetTypes[i]))) {
752                    boolean b1 = source.isBridge();
753                    boolean b2 = target.isBridge();
754                    // must not be bridge methods
755                    if (!b1 && !b2) {
756                        return false;
757                    }
758                }
759            }
760        }
761
762        // the have same name, return type and parameter list, so its overriding
763        return true;
764    }
765
766    /**
767     * Returns a list of methods which are annotated with the given annotation
768     *
769     * @param type the type to reflect on
770     * @param annotationType the annotation type
771     * @return a list of the methods found
772     */
773    public static List<Method> findMethodsWithAnnotation(Class<?> type,
774                                                         Class<? extends Annotation> annotationType) {
775        return findMethodsWithAnnotation(type, annotationType, false);
776    }
777
778    /**
779     * Returns a list of methods which are annotated with the given annotation
780     *
781     * @param type the type to reflect on
782     * @param annotationType the annotation type
783     * @param checkMetaAnnotations check for meta annotations
784     * @return a list of the methods found
785     */
786    public static List<Method> findMethodsWithAnnotation(Class<?> type,
787                                                         Class<? extends Annotation> annotationType,
788                                                         boolean checkMetaAnnotations) {
789        List<Method> answer = new ArrayList<>();
790        do {
791            Method[] methods = type.getDeclaredMethods();
792            for (Method method : methods) {
793                if (hasAnnotation(method, annotationType, checkMetaAnnotations)) {
794                    answer.add(method);
795                }
796            }
797            type = type.getSuperclass();
798        } while (type != null);
799        return answer;
800    }
801
802    /**
803     * Checks if a Class or Method are annotated with the given annotation
804     *
805     * @param elem the Class or Method to reflect on
806     * @param annotationType the annotation type
807     * @param checkMetaAnnotations check for meta annotations
808     * @return true if annotations is present
809     */
810    public static boolean hasAnnotation(AnnotatedElement elem, Class<? extends Annotation> annotationType,
811                                        boolean checkMetaAnnotations) {
812        if (elem.isAnnotationPresent(annotationType)) {
813            return true;
814        }
815        if (checkMetaAnnotations) {
816            for (Annotation a : elem.getAnnotations()) {
817                for (Annotation meta : a.annotationType().getAnnotations()) {
818                    if (meta.annotationType().getName().equals(annotationType.getName())) {
819                        return true;
820                    }
821                }
822            }
823        }
824        return false;
825    }
826
827    /**
828     * Turns the given object arrays into a meaningful string
829     *
830     * @param objects an array of objects or null
831     * @return a meaningful string
832     */
833    public static String asString(Object[] objects) {
834        if (objects == null) {
835            return "null";
836        } else {
837            StringBuilder buffer = new StringBuilder("{");
838            int counter = 0;
839            for (Object object : objects) {
840                if (counter++ > 0) {
841                    buffer.append(", ");
842                }
843                String text = (object == null) ? "null" : object.toString();
844                buffer.append(text);
845            }
846            buffer.append("}");
847            return buffer.toString();
848        }
849    }
850
851    /**
852     * Returns true if a class is assignable from another class like the
853     * {@link Class#isAssignableFrom(Class)} method but which also includes
854     * coercion between primitive types to deal with Java 5 primitive type
855     * wrapping
856     */
857    public static boolean isAssignableFrom(Class<?> a, Class<?> b) {
858        a = convertPrimitiveTypeToWrapperType(a);
859        b = convertPrimitiveTypeToWrapperType(b);
860        return a.isAssignableFrom(b);
861    }
862
863    /**
864     * Returns if the given {@code clazz} type is a Java primitive array type.
865     *
866     * @param clazz the Java type to be checked
867     * @return {@code true} if the given type is a Java primitive array type
868     */
869    public static boolean isPrimitiveArrayType(Class<?> clazz) {
870        if (clazz != null && clazz.isArray()) {
871            return clazz.getComponentType().isPrimitive();
872        }
873        return false;
874    }
875
876    public static int arrayLength(Object[] pojo) {
877        return pojo.length;
878    }
879
880    /**
881     * Converts primitive types such as int to its wrapper type like
882     * {@link Integer}
883     */
884    public static Class<?> convertPrimitiveTypeToWrapperType(Class<?> type) {
885        Class<?> rc = type;
886        if (type.isPrimitive()) {
887            if (type == int.class) {
888                rc = Integer.class;
889            } else if (type == long.class) {
890                rc = Long.class;
891            } else if (type == double.class) {
892                rc = Double.class;
893            } else if (type == float.class) {
894                rc = Float.class;
895            } else if (type == short.class) {
896                rc = Short.class;
897            } else if (type == byte.class) {
898                rc = Byte.class;
899            } else if (type == boolean.class) {
900                rc = Boolean.class;
901            } else if (type == char.class) {
902                rc = Character.class;
903            }
904        }
905        return rc;
906    }
907
908    /**
909     * Helper method to return the default character set name
910     */
911    public static String getDefaultCharacterSet() {
912        return Charset.defaultCharset().name();
913    }
914
915    /**
916     * Returns the Java Bean property name of the given method, if it is a
917     * setter
918     */
919    public static String getPropertyName(Method method) {
920        String propertyName = method.getName();
921        if (propertyName.startsWith("set") && method.getParameterCount() == 1) {
922            propertyName = propertyName.substring(3, 4).toLowerCase(Locale.ENGLISH) + propertyName.substring(4);
923        }
924        return propertyName;
925    }
926
927    /**
928     * Returns true if the given collection of annotations matches the given type
929     */
930    public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
931        for (Annotation annotation : annotations) {
932            if (type.isInstance(annotation)) {
933                return true;
934            }
935        }
936        return false;
937    }
938
939    /**
940     * Gets the annotation from the given instance.
941     *
942     * @param instance the instance
943     * @param type  the annotation
944     * @return the annotation, or <tt>null</tt> if the instance does not have the given annotation
945     */
946    public static <A extends java.lang.annotation.Annotation> A getAnnotation(Object instance, Class<A> type) {
947        return instance.getClass().getAnnotation(type);
948    }
949
950
951    /**
952     * Converts the given value to the required type or throw a meaningful exception
953     */
954    @SuppressWarnings("unchecked")
955    public static <T> T cast(Class<T> toType, Object value) {
956        if (toType == boolean.class) {
957            return (T) cast(Boolean.class, value);
958        } else if (toType.isPrimitive()) {
959            Class<?> newType = convertPrimitiveTypeToWrapperType(toType);
960            if (newType != toType) {
961                return (T) cast(newType, value);
962            }
963        }
964        try {
965            return toType.cast(value);
966        } catch (ClassCastException e) {
967            throw new IllegalArgumentException("Failed to convert: "
968                + value + " to type: " + toType.getName() + " due to: " + e, e);
969        }
970    }
971
972    /**
973     * Does the given class have a default public no-arg constructor.
974     */
975    public static boolean hasDefaultPublicNoArgConstructor(Class<?> type) {
976        // getConstructors() returns only public constructors
977        for (Constructor<?> ctr : type.getConstructors()) {
978            if (ctr.getParameterCount() == 0) {
979                return true;
980            }
981        }
982        return false;
983    }
984
985    /**
986     * Returns the type of the given object or null if the value is null
987     */
988    public static Object type(Object bean) {
989        return bean != null ? bean.getClass() : null;
990    }
991
992    /**
993     * Evaluate the value as a predicate which attempts to convert the value to
994     * a boolean otherwise true is returned if the value is not null
995     */
996    public static boolean evaluateValuePredicate(Object value) {
997        if (value instanceof Boolean) {
998            return (Boolean) value;
999        } else if (value instanceof String) {
1000            if ("true".equalsIgnoreCase((String) value)) {
1001                return true;
1002            } else if ("false".equalsIgnoreCase((String) value)) {
1003                return false;
1004            }
1005        } else if (value instanceof NodeList) {
1006            // is it an empty dom with empty attributes
1007            if (value instanceof Node && ((Node) value).hasAttributes()) {
1008                return true;
1009            }
1010            NodeList list = (NodeList) value;
1011            return list.getLength() > 0;
1012        } else if (value instanceof Collection) {
1013            // is it an empty collection
1014            Collection<?> col = (Collection<?>) value;
1015            return col.size() > 0;
1016        }
1017        return value != null;
1018    }
1019
1020    /**
1021     * Creates an Iterable to walk the exception from the bottom up
1022     * (the last caused by going upwards to the root exception).
1023     *
1024     * @see java.lang.Iterable
1025     * @param exception  the exception
1026     * @return the Iterable
1027     */
1028    public static Iterable<Throwable> createExceptionIterable(Throwable exception) {
1029        List<Throwable> throwables = new ArrayList<>();
1030
1031        Throwable current = exception;
1032        // spool to the bottom of the caused by tree
1033        while (current != null) {
1034            throwables.add(current);
1035            current = current.getCause();
1036        }
1037        Collections.reverse(throwables);
1038
1039        return throwables;
1040    }
1041
1042    /**
1043     * Creates an Iterator to walk the exception from the bottom up
1044     * (the last caused by going upwards to the root exception).
1045     *
1046     * @see Iterator
1047     * @param exception  the exception
1048     * @return the Iterator
1049     */
1050    public static Iterator<Throwable> createExceptionIterator(Throwable exception) {
1051        return createExceptionIterable(exception).iterator();
1052    }
1053
1054    /**
1055     * Retrieves the given exception type from the exception.
1056     * <p/>
1057     * Is used to get the caused exception that typically have been wrapped in some sort
1058     * of Camel wrapper exception
1059     * <p/>
1060     * The strategy is to look in the exception hierarchy to find the first given cause that matches the type.
1061     * Will start from the bottom (the real cause) and walk upwards.
1062     *
1063     * @param type the exception type wanted to retrieve
1064     * @param exception the caused exception
1065     * @return the exception found (or <tt>null</tt> if not found in the exception hierarchy)
1066     */
1067    public static <T> T getException(Class<T> type, Throwable exception) {
1068        if (exception == null) {
1069            return null;
1070        }
1071
1072        //check the suppressed exception first
1073        for (Throwable throwable : exception.getSuppressed()) {
1074            if (type.isInstance(throwable)) {
1075                return type.cast(throwable);
1076            }
1077        }
1078
1079        // walk the hierarchy and look for it
1080        for (final Throwable throwable : createExceptionIterable(exception)) {
1081            if (type.isInstance(throwable)) {
1082                return type.cast(throwable);
1083            }
1084        }
1085
1086        // not found
1087        return null;
1088    }
1089
1090    public static String getIdentityHashCode(Object object) {
1091        return "0x" + Integer.toHexString(System.identityHashCode(object));
1092    }
1093
1094    /**
1095     * Lookup the constant field on the given class with the given name
1096     *
1097     * @param clazz  the class
1098     * @param name   the name of the field to lookup
1099     * @return the value of the constant field, or <tt>null</tt> if not found
1100     */
1101    public static String lookupConstantFieldValue(Class<?> clazz, String name) {
1102        if (clazz == null) {
1103            return null;
1104        }
1105
1106        // remove leading dots
1107        if (name.startsWith(",")) {
1108            name = name.substring(1);
1109        }
1110
1111        for (Field field : clazz.getFields()) {
1112            if (field.getName().equals(name)) {
1113                try {
1114                    Object v = field.get(null);
1115                    return v.toString();
1116                } catch (IllegalAccessException e) {
1117                    // ignore
1118                    return null;
1119                }
1120            }
1121        }
1122
1123        return null;
1124    }
1125
1126    /**
1127     * Is the given value a numeric NaN type
1128     *
1129     * @param value the value
1130     * @return <tt>true</tt> if its a {@link Float#NaN} or {@link Double#NaN}.
1131     */
1132    public static boolean isNaN(Object value) {
1133        return (value instanceof Number)
1134            && (FLOAT_NAN.equals(value) || DOUBLE_NAN.equals(value));
1135    }
1136
1137    /**
1138     * Wraps the caused exception in a {@link RuntimeException} if its not
1139     * already such an exception.
1140     *
1141     * @param e the caused exception
1142     * @return the wrapper exception
1143     * @deprecated Use {@link org.apache.camel.RuntimeCamelException#wrapRuntimeCamelException} instead
1144     */
1145    @Deprecated
1146    public static RuntimeException wrapRuntimeCamelException(Throwable e) {
1147        try {
1148            Class<? extends RuntimeException> clazz = (Class) Class.forName("org.apache.camel.RuntimeException");
1149            if (clazz.isInstance(e)) {
1150                // don't double wrap
1151                return clazz.cast(e);
1152            } else {
1153                return clazz.getConstructor(Throwable.class).newInstance(e);
1154            }
1155        } catch (Throwable t) {
1156            // ignore
1157        }
1158        if (e instanceof RuntimeException) {
1159            // don't double wrap
1160            return (RuntimeException) e;
1161        } else {
1162            return new RuntimeException(e);
1163        }
1164    }
1165}