/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.camel.util;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.apache.camel.RuntimeCamelException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* A number of useful helper methods for working with Objects
*
* @version $Revision: 739202 $
*/
public final class ObjectHelper {
private static final transient Log LOG = LogFactory.getLog(ObjectHelper.class);
/**
* Utility classes should not have a public constructor.
*/
private ObjectHelper() {
}
/**
* @deprecated use the equal method instead. Will be removed in Camel 2.0.
*
* @see #equal(Object, Object)
*/
@Deprecated
public static boolean equals(Object a, Object b) {
return equal(a, b);
}
/**
* A helper method for comparing objects for equality while handling nulls
*/
public static boolean equal(Object a, Object b) {
if (a == b) {
return true;
}
if (a instanceof byte[] && b instanceof byte[]) {
return equalByteArray((byte[]) a, (byte[]) b);
}
return a != null && b != null && a.equals(b);
}
/**
* A helper method for comparing byte arrays for equality while handling nulls
*/
public static boolean equalByteArray(byte[] a, byte[] b) {
if (a == b) {
return true;
}
// loop and compare each byte
if (a != null && b != null && a.length == b.length) {
for (int i = 0; i < a.length; i++) {
if (a[i] != b[i]) {
return false;
}
}
// all bytes are equal
return true;
}
return false;
}
/**
* Returns true if the given object is equal to any of the expected value
*/
public static boolean isEqualToAny(Object object, Object... values) {
for (Object value : values) {
if (equal(object, value)) {
return true;
}
}
return false;
}
/**
* A helper method for performing an ordered comparison on the objects
* handling nulls and objects which do not handle sorting gracefully
*/
public static int compare(Object a, Object b) {
if (a == b) {
return 0;
}
if (a == null) {
return -1;
}
if (b == null) {
return 1;
}
if (a instanceof Comparable) {
Comparable comparable = (Comparable)a;
return comparable.compareTo(b);
} else {
int answer = a.getClass().getName().compareTo(b.getClass().getName());
if (answer == 0) {
answer = a.hashCode() - b.hashCode();
}
return answer;
}
}
public static Boolean toBoolean(Object value) {
if (value instanceof Boolean) {
return (Boolean)value;
}
if (value instanceof String) {
return "true".equalsIgnoreCase(value.toString()) ? Boolean.TRUE : Boolean.FALSE;
}
if (value instanceof Integer) {
return (Integer)value > 0 ? Boolean.TRUE : Boolean.FALSE;
}
return null;
}
/**
* Asserts whether the value is <b>not</b> <tt>null</tt>
*
* @param value the value to test
* @param name the key that resolved the value
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static void notNull(Object value, String name) {
if (value == null) {
throw new IllegalArgumentException(name + " must be specified");
}
}
/**
* Asserts whether the value is <b>not</b> <tt>null</tt>
*
* @param value the value to test
* @param on additional description to indicate where this problem occured (appended as toString())
* @param name the key that resolved the value
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static void notNull(Object value, String name, Object on) {
if (on == null) {
notNull(value, name);
} else if (value == null) {
throw new IllegalArgumentException(name + " must be specified on: " + on);
}
}
/**
* Asserts whether the string is <b>not</b> empty.
*
* @param value the string to test
* @param name the key that resolved the value
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static void notEmpty(String value, String name) {
if (isEmpty(value)) {
throw new IllegalArgumentException(name + " must be specified and not empty");
}
}
/**
* Asserts whether the string is <b>not</b> empty.
*
* @param value the string to test
* @param on additional description to indicate where this problem occured (appended as toString())
* @param name the key that resolved the value
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static void notEmpty(String value, String name, Object on) {
if (on == null) {
notNull(value, name);
} else if (isEmpty(value)) {
throw new IllegalArgumentException(name + " must be specified and not empty on: " + on);
}
}
public static String[] splitOnCharacter(String value, String needle, int count) {
String rc[] = new String[count];
rc[0] = value;
for (int i = 1; i < count; i++) {
String v = rc[i - 1];
int p = v.indexOf(needle);
if (p < 0) {
return rc;
}
rc[i - 1] = v.substring(0, p);
rc[i] = v.substring(p + 1);
}
return rc;
}
/**
* Removes any starting characters on the given text which match the given
* character
*
* @param text the string
* @param ch the initial characters to remove
* @return either the original string or the new substring
*/
public static String removeStartingCharacters(String text, char ch) {
int idx = 0;
while (text.charAt(idx) == ch) {
idx++;
}
if (idx > 0) {
return text.substring(idx);
}
return text;
}
public static String capitalize(String text) {
if (text == null) {
return null;
}
int length = text.length();
if (length == 0) {
return text;
}
String answer = text.substring(0, 1).toUpperCase();
if (length > 1) {
answer += text.substring(1, length);
}
return answer;
}
/**
* Returns true if the collection contains the specified value
*/
@SuppressWarnings("unchecked")
public static boolean contains(Object collectionOrArray, Object value) {
if (collectionOrArray instanceof Collection) {
Collection collection = (Collection)collectionOrArray;
return collection.contains(value);
} else if (collectionOrArray instanceof String && value instanceof String) {
String str = (String) collectionOrArray;
String subStr = (String) value;
return str.contains(subStr);
} else {
Iterator iter = createIterator(collectionOrArray);
while (iter.hasNext()) {
if (equal(value, iter.next())) {
return true;
}
}
}
return false;
}
/**
* Creates an iterator over the value if the value is a collection, an
* Object[] or a primitive type array; otherwise to simplify the caller's
* code, we just create a singleton collection iterator over a single value
*/
@SuppressWarnings("unchecked")
public static Iterator createIterator(Object value) {
if (value == null) {
return Collections.EMPTY_LIST.iterator();
} else if (value instanceof Iterator) {
return (Iterator) value;
} else if (value instanceof Collection) {
Collection collection = (Collection)value;
return collection.iterator();
} else if (value.getClass().isArray()) {
// TODO we should handle primitive array types?
List<Object> list = Arrays.asList((Object[]) value);
return list.iterator();
} else if (value instanceof NodeList) {
// lets iterate through DOM results after performing XPaths
final NodeList nodeList = (NodeList) value;
return new Iterator<Node>() {
int idx = -1;
public boolean hasNext() {
return ++idx < nodeList.getLength();
}
public Node next() {
return nodeList.item(idx);
}
public void remove() {
throw new UnsupportedOperationException();
}
};
} else if (value instanceof String) {
Scanner scanner = new Scanner((String)value);
// use comma as delimiter for String values
scanner.useDelimiter(",");
return scanner;
} else {
return Collections.singletonList(value).iterator();
}
}
/**
* Returns the predicate matching boolean on a {@link List} result set where
* if the first element is a boolean its value is used otherwise this method
* returns true if the collection is not empty
*
* @return <tt>true</tt> if the first element is a boolean and its value is true or
* if the list is non empty
*/
public static boolean matches(List list) {
if (!list.isEmpty()) {
Object value = list.get(0);
if (value instanceof Boolean) {
Boolean flag = (Boolean)value;
return flag.booleanValue();
} else {
// lets assume non-empty results are true
return true;
}
}
return false;
}
/**
* @deprecated will be removed in Camel 2.0 - use isNotEmpty() instead
*/
public static boolean isNotNullAndNonEmpty(String text) {
return isNotEmpty(text);
}
/**
* @deprecated will be removed in Camel 2.0 - use isEmpty() instead
*/
public static boolean isNullOrBlank(String text) {
return isEmpty(text);
}
/**
* Tests whether the value is <tt>null</tt> or an empty string.
*
* @param value the value, if its a String it will be tested for text length as well
* @return true if empty
*/
public static boolean isEmpty(Object value) {
return !isNotEmpty(value);
}
/**
* Tests whether the value is <b>not</b> <tt>null</tt> or an empty string.
*
* @param value the value, if its a String it will be tested for text length as well
* @return true if <b>not</b> empty
*/
public static boolean isNotEmpty(Object value) {
if (value == null) {
return false;
} else if (value instanceof String) {
String text = (String) value;
return text.trim().length() > 0;
} else {
return true;
}
}
/**
* A helper method to access a system property, catching any security
* exceptions
*
* @param name the name of the system property required
* @param defaultValue the default value to use if the property is not
* available or a security exception prevents access
* @return the system property value or the default value if the property is
* not available or security does not allow its access
*/
public static String getSystemProperty(String name, String defaultValue) {
try {
return System.getProperty(name, defaultValue);
} catch (Exception e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Caught security exception accessing system property: " + name + ". Reason: " + e,
e);
}
return defaultValue;
}
}
/**
* A helper method to access a boolean system property, catching any security
* exceptions
*
* @param name the name of the system property required
* @param defaultValue the default value to use if the property is not
* available or a security exception prevents access
* @return the boolean representation of the system property value
* or the default value if the property is not available or
* security does not allow its access
*/
public static boolean getSystemProperty(String name, Boolean defaultValue) {
String result = getSystemProperty(name, defaultValue.toString());
return Boolean.parseBoolean(result);
}
/**
* Returns the type name of the given type or null if the type variable is
* null
*/
public static String name(Class type) {
return type != null ? type.getName() : null;
}
/**
* Returns the type name of the given value
*/
public static String className(Object value) {
return name(value != null ? value.getClass() : null);
}
/**
* Returns the canonical type name of the given value
*/
public static String classCanonicalName(Object value) {
if (value != null) {
return value.getClass().getCanonicalName();
} else {
return null;
}
}
/**
* Attempts to load the given class name using the thread context class
* loader or the class loader used to load this class
*
* @param name the name of the class to load
* @return the class or null if it could not be loaded
*/
public static Class<?> loadClass(String name) {
return loadClass(name, ObjectHelper.class.getClassLoader());
}
/**
* Attempts to load the given class name using the thread context class
* loader or the given class loader
*
* @param name the name of the class to load
* @param loader the class loader to use after the thread context class
* loader
* @return the class or null if it could not be loaded
*/
public static Class<?> loadClass(String name, ClassLoader loader) {
// try context class loader first
Class clazz = doLoadClass(name, Thread.currentThread().getContextClassLoader());
if (clazz == null) {
// then the provided loader
clazz = doLoadClass(name, loader);
}
if (clazz == null) {
// and fallback to the loader the loaded the ObjectHelper class
clazz = doLoadClass(name, ObjectHelper.class.getClassLoader());
}
if (clazz == null) {
LOG.warn("Could not find class: " + name);
}
return clazz;
}
/**
* Loads the given class with the provided classloader (may be null).
* Will ignore any class not found and return null.
*
* @param name the name of the class to load
* @param loader a provided loader (may be null)
* @return the class, or null if it could not be loaded
*/
private static Class<?> doLoadClass(String name, ClassLoader loader) {
ObjectHelper.notEmpty(name, "name");
if (loader == null) {
return null;
}
try {
return loader.loadClass(name);
} catch (ClassNotFoundException e) {
if (LOG.isTraceEnabled()) {
LOG.trace("Can not load class: " + name + " using classloader: " + loader, e);
}
}
return null;
}
/**
* Attempts to load the given resource as a stream using the thread context class
* loader or the class loader used to load this class
*
* @param name the name of the resource to load
* @return the stream or null if it could not be loaded
*/
public static InputStream loadResourceAsStream(String name) {
InputStream in = null;
ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
if (contextClassLoader != null) {
in = contextClassLoader.getResourceAsStream(name);
}
if (in == null) {
in = ObjectHelper.class.getClassLoader().getResourceAsStream(name);
}
return in;
}
/**
* A helper method to invoke a method via reflection and wrap any exceptions
* as {@link RuntimeCamelException} instances
*
* @param method the method to invoke
* @param instance the object instance (or null for static methods)
* @param parameters the parameters to the method
* @return the result of the method invocation
*/
public static Object invokeMethod(Method method, Object instance, Object... parameters) {
try {
return method.invoke(instance, parameters);
} catch (IllegalAccessException e) {
throw new RuntimeCamelException(e);
} catch (InvocationTargetException e) {
throw new RuntimeCamelException(e.getCause());
}
}
/**
* Returns a list of methods which are annotated with the given annotation
*
* @param type the type to reflect on
* @param annotationType the annotation type
* @return a list of the methods found
*/
public static List<Method> findMethodsWithAnnotation(Class<?> type,
Class<? extends Annotation> annotationType) {
return findMethodsWithAnnotation(type, annotationType, false);
}
/**
* Returns a list of methods which are annotated with the given annotation
*
* @param type the type to reflect on
* @param annotationType the annotation type
* @param checkMetaAnnotations check for meta annotations
* @return a list of the methods found
*/
public static List<Method> findMethodsWithAnnotation(Class<?> type,
Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) {
List<Method> answer = new ArrayList<Method>();
do {
Method[] methods = type.getDeclaredMethods();
for (Method method : methods) {
if (hasAnnotation(method, annotationType, checkMetaAnnotations)) {
answer.add(method);
}
}
type = type.getSuperclass();
} while (type != null);
return answer;
}
/**
* Checks if a Class or Method are annotated with the given annotation
*
* @param elem the Class or Method to reflect on
* @param annotationType the annotation type
* @param checkMetaAnnotations check for meta annotations
* @return true if annotations is present
*/
public static boolean hasAnnotation(AnnotatedElement elem,
Class<? extends Annotation> annotationType, boolean checkMetaAnnotations) {
if (elem.isAnnotationPresent(annotationType)) {
return true;
}
if (checkMetaAnnotations) {
for (Annotation a : elem.getAnnotations()) {
for (Annotation meta : a.annotationType().getAnnotations()) {
if (meta.annotationType().getName().equals(annotationType.getName())) {
return true;
}
}
}
}
return false;
}
/**
* Turns the given object arrays into a meaningful string
*
* @param objects an array of objects or null
* @return a meaningful string
*/
public static String asString(Object[] objects) {
if (objects == null) {
return "null";
} else {
StringBuffer buffer = new StringBuffer("{");
int counter = 0;
for (Object object : objects) {
if (counter++ > 0) {
buffer.append(", ");
}
String text = (object == null) ? "null" : object.toString();
buffer.append(text);
}
buffer.append("}");
return buffer.toString();
}
}
/**
* Returns true if a class is assignable from another class like the
* {@link Class#isAssignableFrom(Class)} method but which also includes
* coercion between primitive types to deal with Java 5 primitive type
* wrapping
*/
public static boolean isAssignableFrom(Class a, Class b) {
a = convertPrimitiveTypeToWrapperType(a);
b = convertPrimitiveTypeToWrapperType(b);
return a.isAssignableFrom(b);
}
/**
* Converts primitive types such as int to its wrapper type like
* {@link Integer}
*/
public static Class convertPrimitiveTypeToWrapperType(Class type) {
Class rc = type;
if (type.isPrimitive()) {
if (type == int.class) {
rc = Integer.class;
} else if (type == long.class) {
rc = Long.class;
} else if (type == double.class) {
rc = Double.class;
} else if (type == float.class) {
rc = Float.class;
} else if (type == short.class) {
rc = Short.class;
} else if (type == byte.class) {
rc = Byte.class;
// TODO: Why is boolean disabled
/*
} else if (type == boolean.class) {
rc = Boolean.class;
*/
}
}
return rc;
}
/**
* Helper method to return the default character set name
*/
public static String getDefaultCharacterSet() {
return Charset.defaultCharset().name();
}
/**
* Returns the Java Bean property name of the given method, if it is a setter
*/
public static String getPropertyName(Method method) {
String propertyName = method.getName();
if (propertyName.startsWith("set") && method.getParameterTypes().length == 1) {
propertyName = propertyName.substring(3, 4).toLowerCase() + propertyName.substring(4);
}
return propertyName;
}
/**
* Returns true if the given collection of annotations matches the given type
*/
public static boolean hasAnnotation(Annotation[] annotations, Class<?> type) {
for (Annotation annotation : annotations) {
if (type.isInstance(annotation)) {
return true;
}
}
return false;
}
/**
* Closes the given resource if it is available, logging any closing exceptions to the given log
*
* @param closeable the object to close
* @param name the name of the resource
* @param log the log to use when reporting closure warnings
*/
public static void close(Closeable closeable, String name, Log log) {
if (closeable != null) {
try {
closeable.close();
} catch (IOException e) {
if (log != null) {
log.warn("Could not close: " + name + ". Reason: " + e, e);
}
}
}
}
/**
* Converts the given value to the required type or throw a meaningful exception
*/
public static <T> T cast(Class<T> toType, Object value) {
if (toType == boolean.class) {
return (T)cast(Boolean.class, value);
} else if (toType.isPrimitive()) {
Class newType = convertPrimitiveTypeToWrapperType(toType);
if (newType != toType) {
return (T)cast(newType, value);
}
}
try {
return toType.cast(value);
} catch (ClassCastException e) {
throw new IllegalArgumentException("Failed to convert: " + value + " to type: "
+ toType.getName() + " due to: " + e, e);
}
}
/**
* A helper method to create a new instance of a type using the default constructor arguments.
*/
public static <T> T newInstance(Class<T> type) {
try {
return type.newInstance();
} catch (InstantiationException e) {
throw new RuntimeCamelException(e);
} catch (IllegalAccessException e) {
throw new RuntimeCamelException(e);
}
}
/**
* A helper method to create a new instance of a type using the default constructor arguments.
*/
public static <T> T newInstance(Class<?> actualType, Class<T> expectedType) {
try {
Object value = actualType.newInstance();
return cast(expectedType, value);
} catch (InstantiationException e) {
throw new RuntimeCamelException();
} catch (IllegalAccessException e) {
throw new RuntimeCamelException(e);
}
}
/**
* Returns true if the given name is a valid java identifier
*/
public static boolean isJavaIdentifier(String name) {
if (name == null) {
return false;
}
int size = name.length();
if (size < 1) {
return false;
}
if (Character.isJavaIdentifierStart(name.charAt(0))) {
for (int i = 1; i < size; i++) {
if (!Character.isJavaIdentifierPart(name.charAt(i))) {
return false;
}
}
return true;
}
return false;
}
/**
* Returns the type of the given object or null if the value is null
*/
public static Object type(Object bean) {
return bean != null ? bean.getClass() : null;
}
/**
* Evaluate the value as a predicate which attempts to convert the value to
* a boolean otherwise true is returned if the value is not null
*/
public static boolean evaluateValuePredicate(Object value) {
if (value instanceof Boolean) {
Boolean aBoolean = (Boolean)value;
return aBoolean.booleanValue();
} else if (value instanceof String) {
if ("true".equals(value)) {
return true;
} else if ("false".equals(value)) {
return false;
}
}
return value != null;
}
/**
* Wraps the caused exception in a {@link RuntimeCamelException} if its not already such an exception.
*
* @param e the caused exception
* @return the wrapper exception
*/
public static RuntimeCamelException wrapRuntimeCamelException(Throwable e) {
if (e instanceof RuntimeCamelException) {
// don't double wrap if already a RuntimeCamelException
return (RuntimeCamelException) e;
} else {
return new RuntimeCamelException(e);
}
}
}