001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.camel.util;
018    
019    import java.io.Closeable;
020    import java.io.IOException;
021    import java.io.InputStream;
022    import java.lang.annotation.Annotation;
023    import java.lang.reflect.InvocationTargetException;
024    import java.lang.reflect.Method;
025    import java.nio.charset.Charset;
026    import java.util.ArrayList;
027    import java.util.Arrays;
028    import java.util.Collection;
029    import java.util.Collections;
030    import java.util.Iterator;
031    import java.util.List;
032    
033    import org.w3c.dom.Node;
034    import org.w3c.dom.NodeList;
035    
036    
037    import org.apache.camel.RuntimeCamelException;
038    import org.apache.commons.logging.Log;
039    import org.apache.commons.logging.LogFactory;
040    
041    
042    /**
043     * A number of useful helper methods for working with Objects
044     *
045     * @version $Revision: 51090 $
046     */
047    public final class ObjectHelper {
048        private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class);
049    
050        /**
051         * Utility classes should not have a public constructor.
052         */
053        private ObjectHelper() {
054        }
055    
056        /**
057         * @deprecated use the equal method instead. Will be removed in Camel 2.0.
058         *
059         * @see #equal(Object, Object)
060         */
061        @Deprecated
062        public static boolean equals(Object a, Object b) {
063            return equal(a, b);
064        }
065    
066        /**
067         * A helper method for comparing objects for equality while handling nulls
068         */
069        public static boolean equal(Object a, Object b) {
070            if (a == b) {
071                return true;
072            }
073    
074            if (a instanceof byte[] && b instanceof byte[]) {
075                return equalByteArray((byte[]) a, (byte[]) b);
076            }
077    
078            return a != null && b != null && a.equals(b);
079        }
080    
081        /**
082         * A helper method for comparing byte arrays for equality while handling nulls
083         */
084        public static boolean equalByteArray(byte[] a, byte[] b) {
085            if (a == b) {
086                return true;
087            }
088    
089            // loop and compare each byte
090            if (a != null && b != null && a.length == b.length) {
091                for (int i = 0; i < a.length; i++) {
092                    if (a[i] != b[i]) {
093                        return false;
094                    }
095                }
096                // all bytes are equal
097                return true;
098            }
099    
100            return false;
101        }
102    
103        /**
104         * Returns true if the given object is equal to any of the expected value
105         */
106        public static boolean isEqualToAny(Object object, Object... values) {
107            for (Object value : values) {
108                if (equal(object, value)) {
109                    return true;
110                }
111            }
112            return false;
113        }
114    
115        /**
116         * A helper method for performing an ordered comparison on the objects
117         * handling nulls and objects which do not handle sorting gracefully
118         */
119        public static int compare(Object a, Object b) {
120            if (a == b) {
121                return 0;
122            }
123            if (a == null) {
124                return -1;
125            }
126            if (b == null) {
127                return 1;
128            }
129            if (a instanceof Comparable) {
130                Comparable comparable = (Comparable)a;
131                return comparable.compareTo(b);
132            } else {
133                int answer = a.getClass().getName().compareTo(b.getClass().getName());
134                if (answer == 0) {
135                    answer = a.hashCode() - b.hashCode();
136                }
137                return answer;
138            }
139        }
140    
141        public static Boolean toBoolean(Object value) {
142            if (value instanceof Boolean) {
143                return (Boolean)value;
144            }
145            if (value instanceof String) {
146                return "true".equalsIgnoreCase(value.toString()) ? Boolean.TRUE : Boolean.FALSE;
147            }
148            if (value instanceof Integer) {
149                return (Integer)value > 0 ? Boolean.TRUE : Boolean.FALSE;
150            }
151            return null;
152        }
153    
154        public static void notNull(Object value, String name) {
155            if (value == null) {
156                throw new IllegalArgumentException(name + " must be specified");
157            }
158        }
159    
160        public static String[] splitOnCharacter(String value, String needle, int count) {
161            String rc[] = new String[count];
162            rc[0] = value;
163            for (int i = 1; i < count; i++) {
164                String v = rc[i - 1];
165                int p = v.indexOf(needle);
166                if (p < 0) {
167                    return rc;
168                }
169                rc[i - 1] = v.substring(0, p);
170                rc[i] = v.substring(p + 1);
171            }
172            return rc;
173        }
174    
175        /**
176         * Removes any starting characters on the given text which match the given
177         * character
178         *
179         * @param text the string
180         * @param ch the initial characters to remove
181         * @return either the original string or the new substring
182         */
183        public static String removeStartingCharacters(String text, char ch) {
184            int idx = 0;
185            while (text.charAt(idx) == ch) {
186                idx++;
187            }
188            if (idx > 0) {
189                return text.substring(idx);
190            }
191            return text;
192        }
193    
194        public static String capitalize(String text) {
195            if (text == null) {
196                return null;
197            }
198            int length = text.length();
199            if (length == 0) {
200                return text;
201            }
202            String answer = text.substring(0, 1).toUpperCase();
203            if (length > 1) {
204                answer += text.substring(1, length);
205            }
206            return answer;
207        }
208    
209    
210        /**
211         * Returns true if the collection contains the specified value
212         */
213        @SuppressWarnings("unchecked")
214        public static boolean contains(Object collectionOrArray, Object value) {
215            if (collectionOrArray instanceof Collection) {
216                Collection collection = (Collection)collectionOrArray;
217                return collection.contains(value);
218            } else if (collectionOrArray instanceof String && value instanceof String) {
219                String str = (String) collectionOrArray;
220                String subStr = (String) value;
221                return str.contains(subStr);
222            } else {
223                Iterator iter = createIterator(collectionOrArray);
224                while (iter.hasNext()) {
225                    if (equal(value, iter.next())) {
226                        return true;
227                    }
228                }
229            }
230            return false;
231        }
232    
233        /**
234         * Creates an iterator over the value if the value is a collection, an
235         * Object[] or a primitive type array; otherwise to simplify the caller's
236         * code, we just create a singleton collection iterator over a single value
237         */
238        @SuppressWarnings("unchecked")
239        public static Iterator createIterator(Object value) {
240            if (value == null) {
241                return Collections.EMPTY_LIST.iterator();
242            } else if (value instanceof Iterator) {
243                return (Iterator) value;
244            } else if (value instanceof Collection) {
245                Collection collection = (Collection)value;
246                return collection.iterator();
247            } else if (value.getClass().isArray()) {
248                // TODO we should handle primitive array types?
249                List<Object> list = Arrays.asList((Object[]) value);
250                return list.iterator();
251            } else if (value instanceof NodeList) {
252                // lets iterate through DOM results after performing XPaths
253                final NodeList nodeList = (NodeList) value;
254                return new Iterator<Node>() {
255                    int idx = -1;
256    
257                    public boolean hasNext() {
258                        return ++idx < nodeList.getLength();
259                    }
260    
261                    public Node next() {
262                        return nodeList.item(idx);
263                    }
264    
265                    public void remove() {
266                        throw new UnsupportedOperationException();
267                    }
268                };
269            } else {
270                return Collections.singletonList(value).iterator();
271            }
272        }
273    
274        /**
275         * Returns the predicate matching boolean on a {@link List} result set where
276         * if the first element is a boolean its value is used otherwise this method
277         * returns true if the collection is not empty
278         *
279         * @return <tt>true</tt> if the first element is a boolean and its value is true or
280         *          if the list is non empty
281         */
282        public static boolean matches(List list) {
283            if (!list.isEmpty()) {
284                Object value = list.get(0);
285                if (value instanceof Boolean) {
286                    Boolean flag = (Boolean)value;
287                    return flag.booleanValue();
288                } else {
289                    // lets assume non-empty results are true
290                    return true;
291                }
292            }
293            return false;
294        }
295    
296        public static boolean isNotNullAndNonEmpty(String text) {
297            return text != null && text.trim().length() > 0;
298        }
299    
300        public static boolean isNullOrBlank(String text) {
301            return text == null || text.trim().length() <= 0;
302        }
303    
304        /**
305         * A helper method to access a system property, catching any security
306         * exceptions
307         *
308         * @param name the name of the system property required
309         * @param defaultValue the default value to use if the property is not
310         *                available or a security exception prevents access
311         * @return the system property value or the default value if the property is
312         *         not available or security does not allow its access
313         */
314        public static String getSystemProperty(String name, String defaultValue) {
315            try {
316                return System.getProperty(name, defaultValue);
317            } catch (Exception e) {
318                if (LOG.isDebugEnabled()) {
319                    LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e,
320                              e);
321                }
322                return defaultValue;
323            }
324        }
325        
326        /**
327         * A helper method to access a boolean system property, catching any security
328         * exceptions
329         *
330         * @param name the name of the system property required
331         * @param defaultValue the default value to use if the property is not
332         *                available or a security exception prevents access
333         * @return the boolean representation of the system property value 
334         *         or the default value if the property is not available or 
335         *         security does not allow its access
336         */
337        public static boolean getSystemProperty(String name, Boolean defaultValue) {
338            String result = getSystemProperty(name, defaultValue.toString());
339            return Boolean.parseBoolean(result);
340        }    
341        
342        /**
343         * Returns the type name of the given type or null if the type variable is
344         * null
345         */
346        public static String name(Class type) {
347            return type != null ? type.getName() : null;
348        }
349    
350        /**
351         * Returns the type name of the given value
352         */
353        public static String className(Object value) {
354            return name(value != null ? value.getClass() : null);
355        }
356    
357        /**
358         * Returns the canonical type name of the given value
359         */
360        public static String classCanonicalName(Object value) {
361            if (value != null) {
362                return value.getClass().getCanonicalName();
363            } else {
364                return null;
365            }
366        }
367    
368        /**
369         * Attempts to load the given class name using the thread context class
370         * loader or the class loader used to load this class
371         *
372         * @param name the name of the class to load
373         * @return the class or null if it could not be loaded
374         */
375        public static Class<?> loadClass(String name) {
376            return loadClass(name, ObjectHelper.class.getClassLoader());
377        }
378    
379        /**
380         * Attempts to load the given class name using the thread context class
381         * loader or the given class loader
382         *
383         * @param name the name of the class to load
384         * @param loader the class loader to use after the thread context class
385         *                loader
386         * @return the class or null if it could not be loaded
387         */
388        public static Class<?> loadClass(String name, ClassLoader loader) {
389            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
390            if (contextClassLoader != null) {
391                try {
392                    return contextClassLoader.loadClass(name);
393                } catch (ClassNotFoundException e) {
394                    try {
395                        return loader.loadClass(name);
396                    } catch (ClassNotFoundException e1) {
397                        LOG.debug("Could not find class: " + name + ". Reason: " + e);
398                    }
399                }
400            }
401            return null;
402        }
403    
404        /**
405         * Attempts to load the given resource as a stream using the thread context class
406         * loader or the class loader used to load this class
407         *
408         * @param name the name of the resource to load
409         * @return the stream or null if it could not be loaded
410         */
411        public static InputStream loadResourceAsStream(String name) {
412            InputStream in = null;
413    
414            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
415            if (contextClassLoader != null) {
416                in = contextClassLoader.getResourceAsStream(name);
417            }
418            if (in == null) {
419                in = ObjectHelper.class.getClassLoader().getResourceAsStream(name);
420            }
421    
422            return in;
423        }
424    
425        /**
426         * A helper method to invoke a method via reflection and wrap any exceptions
427         * as {@link RuntimeCamelException} instances
428         *
429         * @param method the method to invoke
430         * @param instance the object instance (or null for static methods)
431         * @param parameters the parameters to the method
432         * @return the result of the method invocation
433         */
434        public static Object invokeMethod(Method method, Object instance, Object... parameters) {
435            try {
436                return method.invoke(instance, parameters);
437            } catch (IllegalAccessException e) {
438                throw new RuntimeCamelException(e);
439            } catch (InvocationTargetException e) {
440                throw new RuntimeCamelException(e.getCause());
441            }
442        }
443    
444        /**
445         * Returns a list of methods which are annotated with the given annotation
446         *
447         * @param type the type to reflect on
448         * @param annotationType the annotation type
449         * @return a list of the methods found
450         */
451        public static List<Method> findMethodsWithAnnotation(Class<?> type,
452                                                             Class<? extends Annotation> annotationType) {
453            List<Method> answer = new ArrayList<Method>();
454            do {
455                Method[] methods = type.getDeclaredMethods();
456                for (Method method : methods) {
457                    if (method.getAnnotation(annotationType) != null) {
458                        answer.add(method);
459                    }
460                }
461                type = type.getSuperclass();
462            } while (type != null);
463            return answer;
464        }
465    
466        /**
467         * Turns the given object arrays into a meaningful string
468         *
469         * @param objects an array of objects or null
470         * @return a meaningful string
471         */
472        public static String asString(Object[] objects) {
473            if (objects == null) {
474                return "null";
475            } else {
476                StringBuffer buffer = new StringBuffer("{");
477                int counter = 0;
478                for (Object object : objects) {
479                    if (counter++ > 0) {
480                        buffer.append(", ");
481                    }
482                    String text = (object == null) ? "null" : object.toString();
483                    buffer.append(text);
484                }
485                buffer.append("}");
486                return buffer.toString();
487            }
488        }
489    
490        /**
491         * Returns true if a class is assignable from another class like the
492         * {@link Class#isAssignableFrom(Class)} method but which also includes
493         * coercion between primitive types to deal with Java 5 primitive type
494         * wrapping
495         */
496        public static boolean isAssignableFrom(Class a, Class b) {
497            a = convertPrimitiveTypeToWrapperType(a);
498            b = convertPrimitiveTypeToWrapperType(b);
499            return a.isAssignableFrom(b);
500        }
501    
502        /**
503         * Converts primitive types such as int to its wrapper type like
504         * {@link Integer}
505         */
506        public static Class convertPrimitiveTypeToWrapperType(Class type) {
507            Class rc = type;
508            if (type.isPrimitive()) {
509                if (type == int.class) {
510                    rc = Integer.class;
511                } else if (type == long.class) {
512                    rc = Long.class;
513                } else if (type == double.class) {
514                    rc = Double.class;
515                } else if (type == float.class) {
516                    rc = Float.class;
517                } else if (type == short.class) {
518                    rc = Short.class;
519                } else if (type == byte.class) {
520                    rc = Byte.class;
521                // TODO: Why is boolean disabled
522    /*
523                } else if (type == boolean.class) {
524                    rc = Boolean.class;
525    */
526                }
527            }
528            return rc;
529        }
530    
531        /**
532         * Helper method to return the default character set name
533         */
534        public static String getDefaultCharacterSet() {
535            return Charset.defaultCharset().name();
536        }
537    
538        /**
539         * Returns the Java Bean property name of the given method, if it is a setter
540         */
541        public static String getPropertyName(Method method) {
542            String propertyName = method.getName();
543            if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) {
544                propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4);
545            }
546            return propertyName;
547        }
548    
549        /**
550         * Returns true if the given collection of annotations matches the given type
551         */
552        public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
553            for (Annotation annotation : annotations) {
554                if (type.isInstance(annotation)) {
555                    return true;
556                }
557            }
558            return false;
559        }
560    
561        /**
562         * Closes the given resource if it is available, logging any closing exceptions to the given log
563         *
564         * @param closeable the object to close
565         * @param name the name of the resource
566         * @param log the log to use when reporting closure warnings
567         */
568        public static void close(Closeable closeable, String name, Log log) {
569            if (closeable != null) {
570                try {
571                    closeable.close();
572                } catch (IOException e) {
573                    if (log != null) {
574                        log.warn("Could not close: " + name + ". Reason: " + e, e);
575                    }
576                }
577            }
578        }
579    
580        /**
581         * Converts the given value to the required type or throw a meaningful exception
582         */
583        public static <T> T cast(Class<T> toType, Object value) {
584            if (toType == boolean.class) {
585                return (T)cast(Boolean.class, value);
586            } else if (toType.isPrimitive()) {
587                Class newType = convertPrimitiveTypeToWrapperType(toType);
588                if (newType != toType) {
589                    return (T)cast(newType, value);
590                }
591            }
592            try {
593                return toType.cast(value);
594            } catch (ClassCastException e) {
595                throw new IllegalArgumentException("Failed to convert: " + value + " to type: "
596                                                   + toType.getName() + " due to: " + e, e);
597            }
598        }
599    
600        /**
601         * A helper method to create a new instance of a type using the default constructor arguments.
602         */
603        public static <T> T newInstance(Class<T> type) {
604            try {
605                return type.newInstance();
606            } catch (InstantiationException e) {
607                throw new RuntimeCamelException(e.getCause());
608            } catch (IllegalAccessException e) {
609                throw new RuntimeCamelException(e);
610            }
611        }
612    
613        /**
614         * A helper method to create a new instance of a type using the default constructor arguments.
615         */
616        public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) {
617            try {
618                Object value = actualType.newInstance();
619                return cast(expectedType, value);
620            } catch (InstantiationException e) {
621                throw new RuntimeCamelException(e.getCause());
622            } catch (IllegalAccessException e) {
623                throw new RuntimeCamelException(e);
624            }
625        }
626    
627        /**
628         * Returns true if the given name is a valid java identifier
629         */
630        public static boolean isJavaIdentifier(String name) {
631            if (name == null) {
632                return false;
633            }
634            int size = name.length();
635            if (size < 1) {
636                return false;
637            }
638            if (Character.isJavaIdentifierStart(name.charAt(0))) {
639                for (int i = 1; i < size; i++) {
640                    if (!Character.isJavaIdentifierPart(name.charAt(i))) {
641                        return false;
642                    }
643                }
644                return true;
645            }
646            return false;
647        }
648    
649        /**
650         * Returns the type of the given object or null if the value is null
651         */
652        public static Object type(Object bean) {
653            return bean != null ? bean.getClass() : null;
654        }
655    
656        /**
657         * Evaluate the value as a predicate which attempts to convert the value to
658         * a boolean otherwise true is returned if the value is not null
659         */
660        public static boolean evaluateValuePredicate(Object value) {
661            if (value instanceof Boolean) {
662                Boolean aBoolean = (Boolean)value;
663                return aBoolean.booleanValue();
664            }
665            return value != null;
666        }
667    }