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 org.apache.camel.RuntimeCamelException; 020 import org.apache.camel.converter.ObjectConverter; 021 import org.apache.commons.logging.Log; 022 import org.apache.commons.logging.LogFactory; 023 024 import java.lang.annotation.Annotation; 025 import java.lang.reflect.InvocationTargetException; 026 import java.lang.reflect.Method; 027 import java.util.ArrayList; 028 import java.util.Collection; 029 import java.util.Iterator; 030 import java.util.List; 031 032 /** 033 * @version $Revision: 534560 $ 034 */ 035 public class ObjectHelper { 036 private static final transient Log log = LogFactory.getLog(ObjectHelper.class); 037 038 /** 039 * A helper method for comparing objects for equality while handling nulls 040 */ 041 public static boolean equals(Object a, Object b) { 042 if (a == b) { 043 return true; 044 } 045 return a != null && b != null && a.equals(b); 046 } 047 048 /** 049 * A helper method for performing an ordered comparsion on the objects 050 * handling nulls and objects which do not 051 * handle sorting gracefully 052 */ 053 public static int compare(Object a, Object b) { 054 if (a == b) { 055 return 0; 056 } 057 if (a == null) { 058 return -1; 059 } 060 if (b == null) { 061 return 1; 062 } 063 if (a instanceof Comparable) { 064 Comparable comparable = (Comparable) a; 065 return comparable.compareTo(b); 066 } 067 else { 068 int answer = a.getClass().getName().compareTo(b.getClass().getName()); 069 if (answer == 0) { 070 answer = a.hashCode() - b.hashCode(); 071 } 072 return answer; 073 } 074 } 075 076 public static void notNull(Object value, String name) { 077 if (value == null) { 078 throw new IllegalArgumentException("No " + name + " specified"); 079 } 080 } 081 082 public static String[] splitOnCharacter(String value, String needle, int count) { 083 String rc[] = new String[count]; 084 rc[0] = value; 085 for (int i = 1; i < count; i++) { 086 String v = rc[i - 1]; 087 int p = v.indexOf(needle); 088 if (p < 0) { 089 return rc; 090 } 091 rc[i - 1] = v.substring(0, p); 092 rc[i] = v.substring(p + 1); 093 } 094 return rc; 095 } 096 097 /** 098 * Removes any starting characters on the given text which match the given character 099 * 100 * @param text the string 101 * @param ch the initial characters to remove 102 * @return either the original string or the new substring 103 */ 104 public static String removeStartingCharacters(String text, char ch) { 105 int idx = 0; 106 while (text.charAt(idx) == ch) { 107 idx++; 108 } 109 if (idx > 0) { 110 return text.substring(idx); 111 } 112 return text; 113 } 114 115 /** 116 * Returns true if the collection contains the specified value 117 */ 118 public static boolean contains(Object collectionOrArray, Object value) { 119 if (collectionOrArray instanceof Collection) { 120 Collection collection = (Collection) collectionOrArray; 121 return collection.contains(value); 122 } 123 else { 124 Iterator iter = ObjectConverter.iterator(value); 125 while (iter.hasNext()) { 126 if (equals(value, iter.next())) { 127 return true; 128 } 129 } 130 return false; 131 } 132 } 133 134 /** 135 * Returns the predicate matching boolean on a {@link List} result set 136 * where if the first element is a boolean its value is used 137 * otherwise this method returns true if the collection is not empty 138 * 139 * @returns true if the first element is a boolean and its value is true or if the list is non empty 140 */ 141 public static boolean matches(List list) { 142 if (!list.isEmpty()) { 143 Object value = list.get(0); 144 if (value instanceof Boolean) { 145 Boolean flag = (Boolean) value; 146 return flag.booleanValue(); 147 } 148 else { 149 // lets assume non-empty results are true 150 return true; 151 } 152 } 153 return false; 154 } 155 156 public static boolean isNotNullOrBlank(String text) { 157 return text != null && text.trim().length() > 0; 158 } 159 160 /** 161 * A helper method to access a system property, catching any security exceptions 162 * 163 * @param name the name of the system property required 164 * @param defaultValue the default value to use if the property is not available or a security exception prevents access 165 * @return the system property value or the default value if the property is not available or security does not allow its access 166 */ 167 public static String getSystemProperty(String name, String defaultValue) { 168 try { 169 return System.getProperty(name, defaultValue); 170 } 171 catch (Exception e) { 172 if (log.isDebugEnabled()) { 173 log.debug("Caught security exception accessing system property: " + name + ". Reason: " + e, e); 174 } 175 return defaultValue; 176 } 177 } 178 179 /** 180 * Returns the type name of the given type or null if the type variable is null 181 */ 182 public static String name(Class type) { 183 return type != null ? type.getName() : null; 184 } 185 186 /** 187 * Returns the type name of the given value 188 */ 189 public static String className(Object value) { 190 return name(value != null ? value.getClass() : null); 191 } 192 193 /** 194 * Attempts to load the given class name using the thread context class loader 195 * or the class loader used to load this class 196 * 197 * @param name the name of the class to load 198 * @return the class or null if it could not be loaded 199 */ 200 public static Class<?> loadClass(String name) { 201 return loadClass(name, ObjectHelper.class.getClassLoader()); 202 } 203 204 /** 205 * Attempts to load the given class name using the thread context class loader or the given class loader 206 * 207 * @param name the name of the class to load 208 * @param loader the class loader to use after the thread context class loader 209 * @return the class or null if it could not be loaded 210 */ 211 public static Class<?> loadClass(String name, ClassLoader loader) { 212 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader(); 213 if (contextClassLoader != null) { 214 try { 215 return contextClassLoader.loadClass(name); 216 } 217 catch (ClassNotFoundException e) { 218 try { 219 return loader.loadClass(name); 220 } 221 catch (ClassNotFoundException e1) { 222 log.debug("Could not find class: " + name + ". Reason: " + e); 223 } 224 } 225 } 226 return null; 227 } 228 229 /** 230 * A helper method to invoke a method via reflection and wrap any exceptions 231 * as {@link RuntimeCamelException} instances 232 * 233 * @param method the method to invoke 234 * @param instance the object instance (or null for static methods) 235 * @param parameters the parameters to the method 236 * @return the result of the method invocation 237 */ 238 public static Object invokeMethod(Method method, Object instance, Object... parameters) { 239 try { 240 return method.invoke(instance, parameters); 241 } 242 catch (IllegalAccessException e) { 243 throw new RuntimeCamelException(e); 244 } 245 catch (InvocationTargetException e) { 246 throw new RuntimeCamelException(e.getCause()); 247 } 248 } 249 250 /** 251 * Returns a list of methods which are annotated with the given annotation 252 * 253 * @param type the type to reflect on 254 * @param annotationType the annotation type 255 * @return a list of the methods found 256 */ 257 public static List<Method> findMethodsWithAnnotation(Class<?> type, Class<? extends Annotation> annotationType) { 258 List<Method> answer = new ArrayList<Method>(); 259 do { 260 Method[] methods = type.getDeclaredMethods(); 261 for (Method method : methods) { 262 if (method.getAnnotation(annotationType) != null) { 263 answer.add(method); 264 } 265 } 266 type = type.getSuperclass(); 267 } 268 while (type != null); 269 return answer; 270 } 271 272 /** 273 * Turns the given object arrays into a meaningful string 274 * 275 * @param objects an array of objects or null 276 * @return a meaningful string 277 */ 278 public static String asString(Object[] objects) { 279 if (objects == null) { 280 return "null"; 281 } 282 else { 283 StringBuffer buffer = new StringBuffer("{"); 284 int counter = 0; 285 for (Object object : objects) { 286 if (counter++ > 0) { 287 buffer.append(", "); 288 } 289 String text = (object == null) ? "null" : object.toString(); 290 buffer.append(text); 291 } 292 buffer.append("}"); 293 return buffer.toString(); 294 } 295 } 296 }