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ObjectHelper.java
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ObjectHelper.java
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/**
* 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.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Supplier;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A number of useful helper methods for working with Objects
*/
public final class ObjectHelper {
private static final Logger LOG = LoggerFactory.getLogger(ObjectHelper.class);
/**
* Utility classes should not have a public constructor.
*/
private ObjectHelper() {
}
/**
* A helper method for comparing objects for equality while handling nulls
*/
public static boolean equal(Object a, Object b) {
return equal(a, b, false);
}
/**
* A helper method for comparing objects for equality while handling case insensitivity
*/
public static boolean equalIgnoreCase(Object a, Object b) {
return equal(a, b, true);
}
/**
* A helper method for comparing objects for equality while handling nulls
*/
public static boolean equal(final Object a, final Object b, final boolean ignoreCase) {
if (a == b) {
return true;
}
if (a == null || b == null) {
return false;
}
if (ignoreCase) {
if (a instanceof String && b instanceof String) {
return ((String) a).equalsIgnoreCase((String) b);
}
}
if (a.getClass().isArray() && b.getClass().isArray()) {
// uses array based equals
return Objects.deepEquals(a, b);
} else {
// use regular equals
return a.equals(b);
}
}
/**
* A helper method for comparing byte arrays for equality while handling
* nulls
*/
public static boolean equalByteArray(byte[] a, byte[] b) {
return Arrays.equals(a, b);
}
/**
* 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;
}
public static Boolean toBoolean(Object value) {
if (value instanceof Boolean) {
return (Boolean)value;
}
if (value instanceof String) {
return Boolean.valueOf((String)value);
}
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
* @return the passed {@code value} as is
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static <T> T notNull(T value, String name) {
if (value == null) {
throw new IllegalArgumentException(name + " must be specified");
}
return value;
}
/**
* 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 occurred (appended as toString())
* @param name the key that resolved the value
* @return the passed {@code value} as is
* @throws IllegalArgumentException is thrown if assertion fails
*/
public static <T> T notNull(T value, String name, Object on) {
if (on == null) {
notNull(value, name);
} else if (value == null) {
throw new IllegalArgumentException(name + " must be specified on: " + on);
}
return value;
}
/**
* 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>, an empty string or an empty collection/map.
*
* @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 if (value instanceof Collection) {
return !((Collection<?>)value).isEmpty();
} else if (value instanceof Map) {
return !((Map<?, ?>)value).isEmpty();
} else {
return true;
}
}
/**
* Returns the first non null object <tt>null</tt>.
*
* @param values the values
* @return an Optional
*/
public static Optional<Object> firstNotNull(Object... values) {
for (Object value : values) {
if (value != null) {
return Optional.of(value);
}
}
return Optional.empty();
}
/**
* Tests whether the value is <tt>null</tt>, an empty string, an empty collection or a map
*
* @param value the value, if its a String it will be tested for text length as well
* @param supplier the supplier, the supplier to be used to get a value if value is null
*/
public static <T> T supplyIfEmpty(T value, Supplier<T> supplier) {
org.apache.camel.util.ObjectHelper.notNull(supplier, "Supplier");
if (isNotEmpty(value)) {
return value;
}
return supplier.get();
}
/**
* Tests whether the value is <b>not</b> <tt>null</tt>, an empty string, an empty collection or a map
*
* @param value the value, if its a String it will be tested for text length as well
* @param consumer the consumer, the operation to be executed against value if not empty
*/
public static <T> void ifNotEmpty(T value, Consumer<T> consumer) {
if (isNotEmpty(value)) {
consumer.accept(value);
}
}
/**
* 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) {
return (Boolean)value;
} else {
// lets assume non-empty results are true
return true;
}
}
return false;
}
/**
* 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 + ". Will use default value: " + defaultValue, 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 <tt>null</tt> 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 <tt>null</tt> if it could not be loaded
*/
public static Class<?> loadClass(String name, ClassLoader loader) {
return loadClass(name, loader, false);
}
/**
* 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
* @param needToWarn when <tt>true</tt> logs a warning when a class with the given name could not be loaded
* @return the class or <tt>null</tt> if it could not be loaded
*/
public static Class<?> loadClass(String name, ClassLoader loader, boolean needToWarn) {
// must clean the name so its pure java name, eg removing \n or whatever people can do in the Spring XML
name = StringHelper.normalizeClassName(name);
if (org.apache.camel.util.ObjectHelper.isEmpty(name)) {
return null;
}
// Try simple type first
Class<?> clazz = loadSimpleType(name);
if (clazz == null) {
// try context class loader
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) {
if (needToWarn) {
LOG.warn("Cannot find class: {}", name);
} else {
LOG.debug("Cannot find class: {}", name);
}
}
return clazz;
}
/**
* Load a simple type
*
* @param name the name of the class to load
* @return the class or <tt>null</tt> if it could not be loaded
*/
//CHECKSTYLE:OFF
public static Class<?> loadSimpleType(String name) {
// special for byte[] or Object[] as its common to use
if ("java.lang.byte[]".equals(name) || "byte[]".equals(name)) {
return byte[].class;
} else if ("java.lang.Byte[]".equals(name) || "Byte[]".equals(name)) {
return Byte[].class;
} else if ("java.lang.Object[]".equals(name) || "Object[]".equals(name)) {
return Object[].class;
} else if ("java.lang.String[]".equals(name) || "String[]".equals(name)) {
return String[].class;
// and these is common as well
} else if ("java.lang.String".equals(name) || "String".equals(name)) {
return String.class;
} else if ("java.lang.Boolean".equals(name) || "Boolean".equals(name)) {
return Boolean.class;
} else if ("boolean".equals(name)) {
return boolean.class;
} else if ("java.lang.Integer".equals(name) || "Integer".equals(name)) {
return Integer.class;
} else if ("int".equals(name)) {
return int.class;
} else if ("java.lang.Long".equals(name) || "Long".equals(name)) {
return Long.class;
} else if ("long".equals(name)) {
return long.class;
} else if ("java.lang.Short".equals(name) || "Short".equals(name)) {
return Short.class;
} else if ("short".equals(name)) {
return short.class;
} else if ("java.lang.Byte".equals(name) || "Byte".equals(name)) {
return Byte.class;
} else if ("byte".equals(name)) {
return byte.class;
} else if ("java.lang.Float".equals(name) || "Float".equals(name)) {
return Float.class;
} else if ("float".equals(name)) {
return float.class;
} else if ("java.lang.Double".equals(name) || "Double".equals(name)) {
return Double.class;
} else if ("double".equals(name)) {
return double.class;
} else if ("java.lang.Character".equals(name) || "Character".equals(name)) {
return Character.class;
} else if ("char".equals(name)) {
return char.class;
}
return null;
}
//CHECKSTYLE:ON
/**
* 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) {
StringHelper.notEmpty(name, "name");
if (loader == null) {
return null;
}
try {
LOG.trace("Loading class: {} using classloader: {}", name, loader);
return loader.loadClass(name);
} catch (ClassNotFoundException e) {
if (LOG.isTraceEnabled()) {
LOG.trace("Cannot 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) {
return loadResourceAsStream(name, null);
}
/**
* Attempts to load the given resource as a stream using
* first the given class loader, then the thread context
* class loader and finally the class loader used to load this class
*
* @param name the name of the resource to load
* @param loader optional classloader to attempt first
* @return the stream or null if it could not be loaded
*/
public static InputStream loadResourceAsStream(String name, ClassLoader loader) {
try {
URL res = loadResourceAsURL(name);
return res != null ? res.openStream() : null;
} catch (IOException 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 URL loadResourceAsURL(String name) {
return loadResourceAsURL(name, 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
* @param loader optional classloader to attempt first
* @return the stream or null if it could not be loaded
*/
public static URL loadResourceAsURL(String name, ClassLoader loader) {
URL url = null;
String resolvedName = resolveUriPath(name);
// #1 First, try the given class loader
if (loader != null) {
url = loader.getResource(resolvedName);
if (url != null) return url;
}
// #2 Next, is the TCCL
ClassLoader tccl = Thread.currentThread().getContextClassLoader();
if (tccl != null) {
url = tccl.getResource(resolvedName);
if (url != null) return url;
// #3 The TCCL may be able to see camel-core, but not META-INF resources
try {
Class<?> clazz = tccl.loadClass("org.apache.camel.impl.DefaultCamelContext");
url = clazz.getClassLoader().getResource(resolvedName);
if (url != null) return url;
} catch (ClassNotFoundException e) {
// ignore
}
}
// #4 Last, for the unlikely case that stuff can be loaded from camel-util
url = ObjectHelper.class.getClassLoader().getResource(resolvedName);
if (url != null) return url;
url = ObjectHelper.class.getResource(resolvedName);
return url;
}
/**
* Attempts to load the given resources from the given package name using the thread context
* class loader or the class loader used to load this class
*
* @param uri the name of the package to load its resources
* @return the URLs for the resources or null if it could not be loaded
*/
public static Enumeration<URL> loadResourcesAsURL(String uri) {
return loadResourcesAsURL(uri, null);
}
/**
* Attempts to load the given resources from the given package name using the thread context
* class loader or the class loader used to load this class
*
* @param uri the name of the package to load its resources
* @param loader optional classloader to attempt first
* @return the URLs for the resources or null if it could not be loaded
*/
public static Enumeration<URL> loadResourcesAsURL(String uri, ClassLoader loader) {
Enumeration<URL> res = null;
// #1 First, try the given class loader
if (loader != null) {
try {
res = loader.getResources(uri);
if (res != null) return res;
} catch (IOException e) {
// ignore
}
}
// #2 Next, is the TCCL
ClassLoader tccl = Thread.currentThread().getContextClassLoader();
if (tccl != null) {
try {
res = tccl.getResources(uri);
if (res != null) return res;
} catch (IOException e1) {
// ignore
}
// #3 The TCCL may be able to see camel-core, but not META-INF resources
try {
Class<?> clazz = tccl.loadClass("org.apache.camel.impl.DefaultCamelContext");
res = clazz.getClassLoader().getResources(uri);
if (res != null) return res;
} catch (ClassNotFoundException | IOException e) {
// ignore
}
}
// #4 Last, for the unlikely case that stuff can be loaded from camel-util
try {
res = ObjectHelper.class.getClassLoader().getResources(uri);
} catch (IOException e) {
// ignore
}
return res;
}
/**
* Helper operation used to remove relative path notation from
* resources. Most critical for resources on the Classpath
* as resource loaders will not resolve the relative paths correctly.
*
* @param name the name of the resource to load
* @return the modified or unmodified string if there were no changes
*/
private static String resolveUriPath(String name) {
// compact the path and use / as separator as that's used for loading resources on the classpath
return FileUtil.compactPath(name, '/');
}
/**
* Tests whether the target method overrides the source method.
* <p/>
* Tests whether they have the same name, return type, and parameter list.
*
* @param source the source method
* @param target the target method
* @return <tt>true</tt> if it override, <tt>false</tt> otherwise
*/
public static boolean isOverridingMethod(Method source, Method target) {
return isOverridingMethod(source, target, true);
}
/**
* Tests whether the target method overrides the source method.
* <p/>
* Tests whether they have the same name, return type, and parameter list.
*
* @param source the source method
* @param target the target method
* @param exact <tt>true</tt> if the override must be exact same types, <tt>false</tt> if the types should be assignable
* @return <tt>true</tt> if it override, <tt>false</tt> otherwise
*/
public static boolean isOverridingMethod(Method source, Method target, boolean exact) {
return isOverridingMethod(target.getDeclaringClass(), source, target, exact);
}
/**
* Tests whether the target method overrides the source method from the
* inheriting class.
* <p/>
* Tests whether they have the same name, return type, and parameter list.
*
* @param inheritingClass the class inheriting the target method overriding
* the source method
* @param source the source method
* @param target the target method
* @param exact <tt>true</tt> if the override must be exact same types,
* <tt>false</tt> if the types should be assignable
* @return <tt>true</tt> if it override, <tt>false</tt> otherwise
*/
public static boolean isOverridingMethod(Class<?> inheritingClass, Method source, Method target, boolean exact) {
if (source.equals(target)) {
return true;
} else if (target.getDeclaringClass().isAssignableFrom(source.getDeclaringClass())) {
return false;
} else if (!source.getDeclaringClass().isAssignableFrom(inheritingClass) || !target.getDeclaringClass().isAssignableFrom(inheritingClass)) {
return false;
}
if (!source.getName().equals(target.getName())) {
return false;
}
if (exact) {
if (!source.getReturnType().equals(target.getReturnType())) {
return false;
}
} else {
if (!source.getReturnType().isAssignableFrom(target.getReturnType())) {
boolean b1 = source.isBridge();
boolean b2 = target.isBridge();
// must not be bridge methods
if (!b1 && !b2) {
return false;
}
}
}
// must have same number of parameter types
if (source.getParameterCount() != target.getParameterCount()) {
return false;
}
Class<?>[] sourceTypes = source.getParameterTypes();
Class<?>[] targetTypes = target.getParameterTypes();
// test if parameter types is the same as well
for (int i = 0; i < source.getParameterCount(); i++) {
if (exact) {
if (!(sourceTypes[i].equals(targetTypes[i]))) {
return false;
}
} else {
if (!(sourceTypes[i].isAssignableFrom(targetTypes[i]))) {
boolean b1 = source.isBridge();
boolean b2 = target.isBridge();
// must not be bridge methods
if (!b1 && !b2) {
return false;
}
}
}
}
// the have same name, return type and parameter list, so its overriding
return true;
}
/**
* 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<>();
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 {
StringBuilder buffer = new StringBuilder("{");
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);
}
/**
* Returns if the given {@code clazz} type is a Java primitive array type.
*
* @param clazz the Java type to be checked
* @return {@code true} if the given type is a Java primitive array type
*/
public static boolean isPrimitiveArrayType(Class<?> clazz) {
if (clazz != null && clazz.isArray()) {
return clazz.getComponentType().isPrimitive();
}
return false;
}
public static int arrayLength(Object[] pojo) {
return pojo.length;
}
/**
* 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;
} else if (type == boolean.class) {
rc = Boolean.class;
} else if (type == char.class) {
rc = Character.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.getParameterCount() == 1) {
propertyName = propertyName.substring(3, 4).toLowerCase(Locale.ENGLISH) + 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;
}
/**
* Gets the annotation from the given instance.
*
* @param instance the instance
* @param type the annotation
* @return the annotation, or <tt>null</tt> if the instance does not have the given annotation
*/
public static <A extends java.lang.annotation.Annotation> A getAnnotation(Object instance, Class<A> type) {
return instance.getClass().getAnnotation(type);
}
/**
* Converts the given value to the required type or throw a meaningful exception
*/
@SuppressWarnings("unchecked")
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);
}
}
/**
* Does the given class have a default public no-arg constructor.
*/
public static boolean hasDefaultPublicNoArgConstructor(Class<?> type) {
// getConstructors() returns only public constructors
for (Constructor<?> ctr : type.getConstructors()) {
if (ctr.getParameterCount() == 0) {
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) {
return (Boolean)value;
} else if (value instanceof String) {
if ("true".equalsIgnoreCase((String)value)) {
return true;
} else if ("false".equalsIgnoreCase((String)value)) {
return false;
}
} else if (value instanceof NodeList) {
// is it an empty dom with empty attributes
if (value instanceof Node && ((Node)value).hasAttributes()) {
return true;
}
NodeList list = (NodeList) value;
return list.getLength() > 0;
} else if (value instanceof Collection) {
// is it an empty collection
Collection<?> col = (Collection<?>) value;
return col.size() > 0;
}
return value != null;
}