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: 707294 $
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        public static void notNull(Object value, String name) {
156            if (value == null) {
157                throw new IllegalArgumentException(name + " must be specified");
158            }
159        }
160    
161        public static String[] splitOnCharacter(String value, String needle, int count) {
162            String rc[] = new String[count];
163            rc[0] = value;
164            for (int i = 1; i < count; i++) {
165                String v = rc[i - 1];
166                int p = v.indexOf(needle);
167                if (p < 0) {
168                    return rc;
169                }
170                rc[i - 1] = v.substring(0, p);
171                rc[i] = v.substring(p + 1);
172            }
173            return rc;
174        }
175    
176        /**
177         * Removes any starting characters on the given text which match the given
178         * character
179         *
180         * @param text the string
181         * @param ch the initial characters to remove
182         * @return either the original string or the new substring
183         */
184        public static String removeStartingCharacters(String text, char ch) {
185            int idx = 0;
186            while (text.charAt(idx) == ch) {
187                idx++;
188            }
189            if (idx > 0) {
190                return text.substring(idx);
191            }
192            return text;
193        }
194    
195        public static String capitalize(String text) {
196            if (text == null) {
197                return null;
198            }
199            int length = text.length();
200            if (length == 0) {
201                return text;
202            }
203            String answer = text.substring(0, 1).toUpperCase();
204            if (length > 1) {
205                answer += text.substring(1, length);
206            }
207            return answer;
208        }
209    
210    
211        /**
212         * Returns true if the collection contains the specified value
213         */
214        @SuppressWarnings("unchecked")
215        public static boolean contains(Object collectionOrArray, Object value) {
216            if (collectionOrArray instanceof Collection) {
217                Collection collection = (Collection)collectionOrArray;
218                return collection.contains(value);
219            } else if (collectionOrArray instanceof String && value instanceof String) {
220                String str = (String) collectionOrArray;
221                String subStr = (String) value;
222                return str.contains(subStr);
223            } else {
224                Iterator iter = createIterator(collectionOrArray);
225                while (iter.hasNext()) {
226                    if (equal(value, iter.next())) {
227                        return true;
228                    }
229                }
230            }
231            return false;
232        }
233    
234        /**
235         * Creates an iterator over the value if the value is a collection, an
236         * Object[] or a primitive type array; otherwise to simplify the caller's
237         * code, we just create a singleton collection iterator over a single value
238         */
239        @SuppressWarnings("unchecked")
240        public static Iterator createIterator(Object value) {
241            if (value == null) {
242                return Collections.EMPTY_LIST.iterator();
243            } else if (value instanceof Iterator) {
244                return (Iterator) value;
245            } else if (value instanceof Collection) {
246                Collection collection = (Collection)value;
247                return collection.iterator();
248            } else if (value.getClass().isArray()) {
249                // TODO we should handle primitive array types?
250                List<Object> list = Arrays.asList((Object[]) value);
251                return list.iterator();
252            } else if (value instanceof NodeList) {
253                // lets iterate through DOM results after performing XPaths
254                final NodeList nodeList = (NodeList) value;
255                return new Iterator<Node>() {
256                    int idx = -1;
257    
258                    public boolean hasNext() {
259                        return ++idx < nodeList.getLength();
260                    }
261    
262                    public Node next() {
263                        return nodeList.item(idx);
264                    }
265    
266                    public void remove() {
267                        throw new UnsupportedOperationException();
268                    }
269                };
270            } else {
271                return Collections.singletonList(value).iterator();
272            }
273        }
274    
275        /**
276         * Returns the predicate matching boolean on a {@link List} result set where
277         * if the first element is a boolean its value is used otherwise this method
278         * returns true if the collection is not empty
279         *
280         * @return <tt>true</tt> if the first element is a boolean and its value is true or
281         *          if the list is non empty
282         */
283        public static boolean matches(List list) {
284            if (!list.isEmpty()) {
285                Object value = list.get(0);
286                if (value instanceof Boolean) {
287                    Boolean flag = (Boolean)value;
288                    return flag.booleanValue();
289                } else {
290                    // lets assume non-empty results are true
291                    return true;
292                }
293            }
294            return false;
295        }
296    
297        public static boolean isNotNullAndNonEmpty(String text) {
298            return text != null && text.trim().length() > 0;
299        }
300    
301        public static boolean isNullOrBlank(String text) {
302            return text == null || text.trim().length() <= 0;
303        }
304    
305        /**
306         * A helper method to access a system property, catching any security
307         * exceptions
308         *
309         * @param name the name of the system property required
310         * @param defaultValue the default value to use if the property is not
311         *                available or a security exception prevents access
312         * @return the system property value or the default value if the property is
313         *         not available or security does not allow its access
314         */
315        public static String getSystemProperty(String name, String defaultValue) {
316            try {
317                return System.getProperty(name, defaultValue);
318            } catch (Exception e) {
319                if (LOG.isDebugEnabled()) {
320                    LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e,
321                              e);
322                }
323                return defaultValue;
324            }
325        }
326        
327        /**
328         * A helper method to access a boolean system property, catching any security
329         * exceptions
330         *
331         * @param name the name of the system property required
332         * @param defaultValue the default value to use if the property is not
333         *                available or a security exception prevents access
334         * @return the boolean representation of the system property value 
335         *         or the default value if the property is not available or 
336         *         security does not allow its access
337         */
338        public static boolean getSystemProperty(String name, Boolean defaultValue) {
339            String result = getSystemProperty(name, defaultValue.toString());
340            return Boolean.parseBoolean(result);
341        }    
342        
343        /**
344         * Returns the type name of the given type or null if the type variable is
345         * null
346         */
347        public static String name(Class type) {
348            return type != null ? type.getName() : null;
349        }
350    
351        /**
352         * Returns the type name of the given value
353         */
354        public static String className(Object value) {
355            return name(value != null ? value.getClass() : null);
356        }
357    
358        /**
359         * Returns the canonical type name of the given value
360         */
361        public static String classCanonicalName(Object value) {
362            if (value != null) {
363                return value.getClass().getCanonicalName();
364            } else {
365                return null;
366            }
367        }
368    
369        /**
370         * Attempts to load the given class name using the thread context class
371         * loader or the class loader used to load this class
372         *
373         * @param name the name of the class to load
374         * @return the class or null if it could not be loaded
375         */
376        public static Class<?> loadClass(String name) {
377            return loadClass(name, ObjectHelper.class.getClassLoader());
378        }
379    
380        /**
381         * Attempts to load the given class name using the thread context class
382         * loader or the given class loader
383         *
384         * @param name the name of the class to load
385         * @param loader the class loader to use after the thread context class
386         *                loader
387         * @return the class or null if it could not be loaded
388         */
389        public static Class<?> loadClass(String name, ClassLoader loader) {
390            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
391            if (contextClassLoader != null) {
392                try {
393                    return contextClassLoader.loadClass(name);
394                } catch (ClassNotFoundException e) {
395                    try {
396                        return loader.loadClass(name);
397                    } catch (ClassNotFoundException e1) {
398                        LOG.debug("Could not find class: " + name + ". Reason: " + e);
399                    }
400                }
401            }
402            return null;
403        }
404    
405        /**
406         * Attempts to load the given resource as a stream using the thread context class
407         * loader or the class loader used to load this class
408         *
409         * @param name the name of the resource to load
410         * @return the stream or null if it could not be loaded
411         */
412        public static InputStream loadResourceAsStream(String name) {
413            InputStream in = null;
414    
415            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
416            if (contextClassLoader != null) {
417                in = contextClassLoader.getResourceAsStream(name);
418            }
419            if (in == null) {
420                in = ObjectHelper.class.getClassLoader().getResourceAsStream(name);
421            }
422    
423            return in;
424        }
425    
426        /**
427         * A helper method to invoke a method via reflection and wrap any exceptions
428         * as {@link RuntimeCamelException} instances
429         *
430         * @param method the method to invoke
431         * @param instance the object instance (or null for static methods)
432         * @param parameters the parameters to the method
433         * @return the result of the method invocation
434         */
435        public static Object invokeMethod(Method method, Object instance, Object... parameters) {
436            try {
437                return method.invoke(instance, parameters);
438            } catch (IllegalAccessException e) {
439                throw new RuntimeCamelException(e);
440            } catch (InvocationTargetException e) {
441                throw new RuntimeCamelException(e.getCause());
442            }
443        }
444    
445        /**
446         * Returns a list of methods which are annotated with the given annotation
447         *
448         * @param type the type to reflect on
449         * @param annotationType the annotation type
450         * @return a list of the methods found
451         */
452        public static List<Method> findMethodsWithAnnotation(Class<?> type,
453                Class<? extends Annotation> annotationType) {
454            return findMethodsWithAnnotation(type, annotationType, false);
455        }
456        
457        /**
458         * Returns a list of methods which are annotated with the given annotation
459         *
460         * @param type the type to reflect on
461         * @param annotationType the annotation type
462         * @param checkMetaAnnotations check for meta annotations
463         * @return a list of the methods found
464         */
465        public static List<Method> findMethodsWithAnnotation(Class<?> type,
466                Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) {
467            List<Method> answer = new ArrayList<Method>();
468            do {
469                Method[] methods = type.getDeclaredMethods();
470                for (Method method : methods) {
471                    if (hasAnnotation(method, annotationType, checkMetaAnnotations)) {
472                        answer.add(method);
473                    }
474                }
475                type = type.getSuperclass();
476            } while (type != null);
477            return answer;
478        }
479    
480        /**
481         * Checks if a Class or Method are annotated with the given annotation
482         *
483         * @param elem the Class or Method to reflect on
484         * @param annotationType the annotation type
485         * @param checkMetaAnnotations check for meta annotations
486         * @return true if annotations is present
487         */
488        public static boolean hasAnnotation(AnnotatedElement elem, 
489                Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) {
490            if (elem.isAnnotationPresent(annotationType)) {
491                return true;
492            }
493            if (checkMetaAnnotations) {
494                for (Annotation a : elem.getAnnotations()) {
495                    for (Annotation meta : a.annotationType().getAnnotations()) {
496                        if (meta.annotationType().getName().equals(annotationType.getName())) {
497                            return true;
498                        }
499                    }
500                }
501            }
502            return false;
503        }
504        
505        /**
506         * Turns the given object arrays into a meaningful string
507         *
508         * @param objects an array of objects or null
509         * @return a meaningful string
510         */
511        public static String asString(Object[] objects) {
512            if (objects == null) {
513                return "null";
514            } else {
515                StringBuffer buffer = new StringBuffer("{");
516                int counter = 0;
517                for (Object object : objects) {
518                    if (counter++ > 0) {
519                        buffer.append(", ");
520                    }
521                    String text = (object == null) ? "null" : object.toString();
522                    buffer.append(text);
523                }
524                buffer.append("}");
525                return buffer.toString();
526            }
527        }
528    
529        /**
530         * Returns true if a class is assignable from another class like the
531         * {@link Class#isAssignableFrom(Class)} method but which also includes
532         * coercion between primitive types to deal with Java 5 primitive type
533         * wrapping
534         */
535        public static boolean isAssignableFrom(Class a, Class b) {
536            a = convertPrimitiveTypeToWrapperType(a);
537            b = convertPrimitiveTypeToWrapperType(b);
538            return a.isAssignableFrom(b);
539        }
540    
541        /**
542         * Converts primitive types such as int to its wrapper type like
543         * {@link Integer}
544         */
545        public static Class convertPrimitiveTypeToWrapperType(Class type) {
546            Class rc = type;
547            if (type.isPrimitive()) {
548                if (type == int.class) {
549                    rc = Integer.class;
550                } else if (type == long.class) {
551                    rc = Long.class;
552                } else if (type == double.class) {
553                    rc = Double.class;
554                } else if (type == float.class) {
555                    rc = Float.class;
556                } else if (type == short.class) {
557                    rc = Short.class;
558                } else if (type == byte.class) {
559                    rc = Byte.class;
560                // TODO: Why is boolean disabled
561    /*
562                } else if (type == boolean.class) {
563                    rc = Boolean.class;
564    */
565                }
566            }
567            return rc;
568        }
569    
570        /**
571         * Helper method to return the default character set name
572         */
573        public static String getDefaultCharacterSet() {
574            return Charset.defaultCharset().name();
575        }
576    
577        /**
578         * Returns the Java Bean property name of the given method, if it is a setter
579         */
580        public static String getPropertyName(Method method) {
581            String propertyName = method.getName();
582            if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) {
583                propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4);
584            }
585            return propertyName;
586        }
587    
588        /**
589         * Returns true if the given collection of annotations matches the given type
590         */
591        public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
592            for (Annotation annotation : annotations) {
593                if (type.isInstance(annotation)) {
594                    return true;
595                }
596            }
597            return false;
598        }
599    
600        /**
601         * Closes the given resource if it is available, logging any closing exceptions to the given log
602         *
603         * @param closeable the object to close
604         * @param name the name of the resource
605         * @param log the log to use when reporting closure warnings
606         */
607        public static void close(Closeable closeable, String name, Log log) {
608            if (closeable != null) {
609                try {
610                    closeable.close();
611                } catch (IOException e) {
612                    if (log != null) {
613                        log.warn("Could not close: " + name + ". Reason: " + e, e);
614                    }
615                }
616            }
617        }
618    
619        /**
620         * Converts the given value to the required type or throw a meaningful exception
621         */
622        public static <T> T cast(Class<T> toType, Object value) {
623            if (toType == boolean.class) {
624                return (T)cast(Boolean.class, value);
625            } else if (toType.isPrimitive()) {
626                Class newType = convertPrimitiveTypeToWrapperType(toType);
627                if (newType != toType) {
628                    return (T)cast(newType, value);
629                }
630            }
631            try {
632                return toType.cast(value);
633            } catch (ClassCastException e) {
634                throw new IllegalArgumentException("Failed to convert: " + value + " to type: "
635                                                   + toType.getName() + " due to: " + e, e);
636            }
637        }
638    
639        /**
640         * A helper method to create a new instance of a type using the default constructor arguments.
641         */
642        public static <T> T newInstance(Class<T> type) {
643            try {
644                return type.newInstance();
645            } catch (InstantiationException e) {
646                throw new RuntimeCamelException(e);
647            } catch (IllegalAccessException e) {
648                throw new RuntimeCamelException(e);
649            }
650        }
651    
652        /**
653         * A helper method to create a new instance of a type using the default constructor arguments.
654         */
655        public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) {
656            try {
657                Object value = actualType.newInstance();
658                return cast(expectedType, value);
659            } catch (InstantiationException e) {
660                throw new RuntimeCamelException();
661            } catch (IllegalAccessException e) {
662                throw new RuntimeCamelException(e);
663            }
664        }
665    
666        /**
667         * Returns true if the given name is a valid java identifier
668         */
669        public static boolean isJavaIdentifier(String name) {
670            if (name == null) {
671                return false;
672            }
673            int size = name.length();
674            if (size < 1) {
675                return false;
676            }
677            if (Character.isJavaIdentifierStart(name.charAt(0))) {
678                for (int i = 1; i < size; i++) {
679                    if (!Character.isJavaIdentifierPart(name.charAt(i))) {
680                        return false;
681                    }
682                }
683                return true;
684            }
685            return false;
686        }
687    
688        /**
689         * Returns the type of the given object or null if the value is null
690         */
691        public static Object type(Object bean) {
692            return bean != null ? bean.getClass() : null;
693        }
694    
695        /**
696         * Evaluate the value as a predicate which attempts to convert the value to
697         * a boolean otherwise true is returned if the value is not null
698         */
699        public static boolean evaluateValuePredicate(Object value) {
700            if (value instanceof Boolean) {
701                Boolean aBoolean = (Boolean)value;
702                return aBoolean.booleanValue();
703            } else if (value instanceof String) {
704                if ("true".equals(value)) {
705                    return true;
706                } else if ("false".equals(value)) {
707                    return false;
708                }
709            }
710            return value != null;
711        }
712    
713        /**
714         * Wraps the caused exception in a {@link RuntimeCamelException} if its not already such an exception.
715         *
716         * @param e  the caused exception
717         * @return  the wrapper exception
718         */
719        public static RuntimeCamelException wrapRuntimeCamelException(Throwable e) {
720            if (e instanceof RuntimeCamelException) {
721                // don't double wrap if already a RuntimeCamelException
722                return (RuntimeCamelException) e;
723            } else {
724                return new RuntimeCamelException(e);
725            }
726        }
727    
728    }