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.lang.annotation.Annotation;
022    import java.lang.reflect.InvocationTargetException;
023    import java.lang.reflect.Method;
024    import java.nio.charset.Charset;
025    import java.util.ArrayList;
026    import java.util.Collection;
027    import java.util.Iterator;
028    import java.util.List;
029    
030    import org.apache.camel.RuntimeCamelException;
031    import org.apache.camel.converter.ObjectConverter;
032    import org.apache.commons.logging.Log;
033    import org.apache.commons.logging.LogFactory;
034    
035    /**
036     * A number of useful helper methods for working with Objects
037     *
038     * @version $Revision: 642753 $
039     */
040    public final class ObjectHelper {
041        private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class);
042    
043        /**
044         * Utility classes should not have a public constructor.
045         */
046        private ObjectHelper() {
047        }
048    
049        /**
050         * @deprecated use the equal method instead
051         *
052         * @see #equal(Object, Object)
053         */
054        public static boolean equals(Object a, Object b) {
055            return equal(a, b);
056        }
057    
058        /**
059         * A helper method for comparing objects for equality while handling nulls
060         */
061        public static boolean equal(Object a, Object b) {
062            if (a == b) {
063                return true;
064            }
065    
066            if (a instanceof byte[] && b instanceof byte[]) {
067                return equalByteArray((byte[]) a, (byte[]) b);
068            }
069    
070            return a != null && b != null && a.equals(b);
071        }
072    
073        /**
074         * A helper method for comparing byte arrays for equality while handling nulls
075         */
076        public static boolean equalByteArray(byte[] a, byte[] b) {
077            if (a == b) {
078                return true;
079            }
080    
081            // loop and compare each byte
082            if (a != null && b != null && a.length == b.length) {
083                for (int i = 0; i < a.length; i++) {
084                    if (a[i] != b[i]) {
085                        return false;
086                    }
087                }
088                // all bytes are equal
089                return true;
090            }
091    
092            return false;
093        }
094    
095        /**
096         * Returns true if the given object is equal to any of the expected value
097         */
098        public static boolean isEqualToAny(Object object, Object... values) {
099            for (Object value : values) {
100                if (equal(object, value)) {
101                    return true;
102                }
103            }
104            return false;
105        }
106    
107        /**
108         * A helper method for performing an ordered comparsion on the objects
109         * handling nulls and objects which do not handle sorting gracefully
110         */
111        public static int compare(Object a, Object b) {
112            if (a == b) {
113                return 0;
114            }
115            if (a == null) {
116                return -1;
117            }
118            if (b == null) {
119                return 1;
120            }
121            if (a instanceof Comparable) {
122                Comparable comparable = (Comparable)a;
123                return comparable.compareTo(b);
124            } else {
125                int answer = a.getClass().getName().compareTo(b.getClass().getName());
126                if (answer == 0) {
127                    answer = a.hashCode() - b.hashCode();
128                }
129                return answer;
130            }
131        }
132    
133        public static void notNull(Object value, String name) {
134            if (value == null) {
135                throw new IllegalArgumentException(name + " must be specified");
136            }
137        }
138    
139        public static String[] splitOnCharacter(String value, String needle, int count) {
140            String rc[] = new String[count];
141            rc[0] = value;
142            for (int i = 1; i < count; i++) {
143                String v = rc[i - 1];
144                int p = v.indexOf(needle);
145                if (p < 0) {
146                    return rc;
147                }
148                rc[i - 1] = v.substring(0, p);
149                rc[i] = v.substring(p + 1);
150            }
151            return rc;
152        }
153    
154        /**
155         * Removes any starting characters on the given text which match the given
156         * character
157         *
158         * @param text the string
159         * @param ch the initial characters to remove
160         * @return either the original string or the new substring
161         */
162        public static String removeStartingCharacters(String text, char ch) {
163            int idx = 0;
164            while (text.charAt(idx) == ch) {
165                idx++;
166            }
167            if (idx > 0) {
168                return text.substring(idx);
169            }
170            return text;
171        }
172    
173        public static String capitalize(String text) {
174            int length = text.length();
175            if (text == null || length == 0) {
176                return text;
177            }
178            String answer = text.substring(0, 1).toUpperCase();
179            if (length > 1) {
180                answer += text.substring(1, length);
181            }
182            return answer;
183        }
184    
185    
186        /**
187         * Returns true if the collection contains the specified value
188         */
189        public static boolean contains(Object collectionOrArray, Object value) {
190            if (collectionOrArray instanceof Collection) {
191                Collection collection = (Collection)collectionOrArray;
192                return collection.contains(value);
193            } else if (collectionOrArray instanceof String && value instanceof String) {
194                String str = (String) collectionOrArray;
195                String subStr = (String) value;
196                return str.contains(subStr);
197            } else {
198                Iterator iter = ObjectConverter.iterator(collectionOrArray);
199                while (iter.hasNext()) {
200                    if (equal(value, iter.next())) {
201                        return true;
202                    }
203                }
204                return false;
205            }
206        }
207    
208        /**
209         * Returns the predicate matching boolean on a {@link List} result set where
210         * if the first element is a boolean its value is used otherwise this method
211         * returns true if the collection is not empty
212         *
213         * @return <tt>true</tt> if the first element is a boolean and its value is true or
214         *          if the list is non empty
215         */
216        public static boolean matches(List list) {
217            if (!list.isEmpty()) {
218                Object value = list.get(0);
219                if (value instanceof Boolean) {
220                    Boolean flag = (Boolean)value;
221                    return flag.booleanValue();
222                } else {
223                    // lets assume non-empty results are true
224                    return true;
225                }
226            }
227            return false;
228        }
229    
230        public static boolean isNotNullAndNonEmpty(String text) {
231            return text != null && text.trim().length() > 0;
232        }
233    
234        public static boolean isNullOrBlank(String text) {
235            return text == null || text.trim().length() <= 0;
236        }
237    
238        /**
239         * A helper method to access a system property, catching any security
240         * exceptions
241         *
242         * @param name the name of the system property required
243         * @param defaultValue the default value to use if the property is not
244         *                available or a security exception prevents access
245         * @return the system property value or the default value if the property is
246         *         not available or security does not allow its access
247         */
248        public static String getSystemProperty(String name, String defaultValue) {
249            try {
250                return System.getProperty(name, defaultValue);
251            } catch (Exception e) {
252                if (LOG.isDebugEnabled()) {
253                    LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e,
254                              e);
255                }
256                return defaultValue;
257            }
258        }
259    
260        /**
261         * Returns the type name of the given type or null if the type variable is
262         * null
263         */
264        public static String name(Class type) {
265            return type != null ? type.getName() : null;
266        }
267    
268        /**
269         * Returns the type name of the given value
270         */
271        public static String className(Object value) {
272            return name(value != null ? value.getClass() : null);
273        }
274    
275        /**
276         * Attempts to load the given class name using the thread context class
277         * loader or the class loader used to load this class
278         *
279         * @param name the name of the class to load
280         * @return the class or null if it could not be loaded
281         */
282        public static Class<?> loadClass(String name) {
283            return loadClass(name, ObjectHelper.class.getClassLoader());
284        }
285    
286        /**
287         * Attempts to load the given class name using the thread context class
288         * loader or the given class loader
289         *
290         * @param name the name of the class to load
291         * @param loader the class loader to use after the thread context class
292         *                loader
293         * @return the class or null if it could not be loaded
294         */
295        public static Class<?> loadClass(String name, ClassLoader loader) {
296            ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
297            if (contextClassLoader != null) {
298                try {
299                    return contextClassLoader.loadClass(name);
300                } catch (ClassNotFoundException e) {
301                    try {
302                        return loader.loadClass(name);
303                    } catch (ClassNotFoundException e1) {
304                        LOG.debug("Could not find class: " + name + ". Reason: " + e);
305                    }
306                }
307            }
308            return null;
309        }
310    
311        /**
312         * A helper method to invoke a method via reflection and wrap any exceptions
313         * as {@link RuntimeCamelException} instances
314         *
315         * @param method the method to invoke
316         * @param instance the object instance (or null for static methods)
317         * @param parameters the parameters to the method
318         * @return the result of the method invocation
319         */
320        public static Object invokeMethod(Method method, Object instance, Object... parameters) {
321            try {
322                return method.invoke(instance, parameters);
323            } catch (IllegalAccessException e) {
324                throw new RuntimeCamelException(e);
325            } catch (InvocationTargetException e) {
326                throw new RuntimeCamelException(e.getCause());
327            }
328        }
329    
330        /**
331         * Returns a list of methods which are annotated with the given annotation
332         *
333         * @param type the type to reflect on
334         * @param annotationType the annotation type
335         * @return a list of the methods found
336         */
337        public static List<Method> findMethodsWithAnnotation(Class<?> type,
338                                                             Class<? extends Annotation> annotationType) {
339            List<Method> answer = new ArrayList<Method>();
340            do {
341                Method[] methods = type.getDeclaredMethods();
342                for (Method method : methods) {
343                    if (method.getAnnotation(annotationType) != null) {
344                        answer.add(method);
345                    }
346                }
347                type = type.getSuperclass();
348            } while (type != null);
349            return answer;
350        }
351    
352        /**
353         * Turns the given object arrays into a meaningful string
354         *
355         * @param objects an array of objects or null
356         * @return a meaningful string
357         */
358        public static String asString(Object[] objects) {
359            if (objects == null) {
360                return "null";
361            } else {
362                StringBuffer buffer = new StringBuffer("{");
363                int counter = 0;
364                for (Object object : objects) {
365                    if (counter++ > 0) {
366                        buffer.append(", ");
367                    }
368                    String text = (object == null) ? "null" : object.toString();
369                    buffer.append(text);
370                }
371                buffer.append("}");
372                return buffer.toString();
373            }
374        }
375    
376        /**
377         * Returns true if a class is assignable from another class like the
378         * {@link Class#isAssignableFrom(Class)} method but which also includes
379         * coercion between primitive types to deal with Java 5 primitive type
380         * wrapping
381         */
382        public static boolean isAssignableFrom(Class a, Class b) {
383            a = convertPrimitiveTypeToWrapperType(a);
384            b = convertPrimitiveTypeToWrapperType(b);
385            return a.isAssignableFrom(b);
386        }
387    
388        /**
389         * Converts primitive types such as int to its wrapper type like
390         * {@link Integer}
391         */
392        public static Class convertPrimitiveTypeToWrapperType(Class type) {
393            Class rc = type;
394            if (type.isPrimitive()) {
395                if (type == int.class) {
396                    rc = Integer.class;
397                } else if (type == long.class) {
398                    rc = Long.class;
399                } else if (type == double.class) {
400                    rc = Double.class;
401                } else if (type == float.class) {
402                    rc = Float.class;
403                } else if (type == short.class) {
404                    rc = Short.class;
405                } else if (type == byte.class) {
406                    rc = Byte.class;
407    /*
408                } else if (type == boolean.class) {
409                    rc = Boolean.class;
410    */
411                }
412            }
413            return rc;
414        }
415    
416        /**
417         * Helper method to return the default character set name
418         */
419        public static String getDefaultCharacterSet() {
420            return Charset.defaultCharset().name();
421        }
422    
423        /**
424         * Returns the Java Bean property name of the given method, if it is a setter
425         */
426        public static String getPropertyName(Method method) {
427            String propertyName = method.getName();
428            if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) {
429                propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4);
430            }
431            return propertyName;
432        }
433    
434        /**
435         * Returns true if the given collection of annotations matches the given type
436         */
437        public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
438            for (Annotation annotation : annotations) {
439                if (type.isInstance(annotation)) {
440                    return true;
441                }
442            }
443            return false;
444        }
445    
446        /**
447         * Closes the given resource if it is available, logging any closing exceptions to the given log
448         *
449         * @param closeable the object to close
450         * @param name the name of the resource
451         * @param log the log to use when reporting closure warnings
452         */
453        public static void close(Closeable closeable, String name, Log log) {
454            if (closeable != null) {
455                try {
456                    closeable.close();
457                } catch (IOException e) {
458                    log.warn("Could not close " + name + ". Reason: " + e, e);
459                }
460            }
461        }
462    
463        /**
464         * Converts the given value to the required type or throw a meaningful exception
465         */
466        public static <T> T cast(Class<T> toType, Object value) {
467            if (toType == boolean.class) {
468                return (T)cast(Boolean.class, value);
469            } else if (toType.isPrimitive()) {
470                Class newType = convertPrimitiveTypeToWrapperType(toType);
471                if (newType != toType) {
472                    return (T)cast(newType, value);
473                }
474            }
475            try {
476                return toType.cast(value);
477            } catch (ClassCastException e) {
478                throw new IllegalArgumentException("Failed to convert: " + value + " to type: "
479                                                   + toType.getName() + " due to: " + e, e);
480            }
481        }
482    
483        /**
484         * A helper method to create a new instance of a type using the default constructor arguments.
485         */
486        public static <T> T newInstance(Class<T> type) {
487            try {
488                return type.newInstance();
489            } catch (InstantiationException e) {
490                throw new RuntimeCamelException(e.getCause());
491            } catch (IllegalAccessException e) {
492                throw new RuntimeCamelException(e);
493            }
494        }
495    
496        /**
497         * A helper method to create a new instance of a type using the default constructor arguments.
498         */
499        public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) {
500            try {
501                Object value = actualType.newInstance();
502                return cast(expectedType, value);
503            } catch (InstantiationException e) {
504                throw new RuntimeCamelException(e.getCause());
505            } catch (IllegalAccessException e) {
506                throw new RuntimeCamelException(e);
507            }
508        }
509    
510        /**
511         * Returns true if the given name is a valid java identifier
512         */
513        public static boolean isJavaIdentifier(String name) {
514            if (name == null) {
515                return false;
516            }
517            int size = name.length();
518            if (size < 1) {
519                return false;
520            }
521            if (Character.isJavaIdentifierStart(name.charAt(0))) {
522                for (int i = 1; i < size; i++) {
523                    if (!Character.isJavaIdentifierPart(name.charAt(i))) {
524                        return false;
525                    }
526                }
527                return true;
528            }
529            return false;
530        }
531    
532        /**
533         * returns the type of the given object or null if the value is null
534         */
535        public static Object type(Object bean) {
536            return bean != null ? bean.getClass() : null;
537        }
538    }