org.apache.deltaspike.core.util.ReflectionUtils Maven / Gradle / Ivy
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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.deltaspike.core.util;
import javax.enterprise.inject.Typed;
import java.io.Serializable;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.security.AccessController;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import org.apache.deltaspike.core.util.securitymanaged.SetAccessiblePrivilegedAction;
/**
* Utilities for common reflection based actions. Some are basic Java Reflection based, others are CDI based.
*/
//X TODO: Look at merging this with some of the other classes from CODI, or if they're really needed
//X TODO: Also some methods need JavaDoc
@Typed()
public abstract class ReflectionUtils
{
private ReflectionUtils()
{
// prevent instantiation
}
/**
* Get all the declared fields on the class hierarchy. This will
* return overridden fields.
*
* @param clazz The class to search
* @return the set of all declared fields or an empty set if there are none
*/
public static Set getAllDeclaredFields(Class clazz)
{
HashSet fields = new HashSet();
for (Class c = clazz; c != null && c != Object.class; c = c.getSuperclass())
{
Collections.addAll(fields, c.getDeclaredFields());
}
return fields;
}
/**
* Search the class hierarchy for a field with the given name. Will return
* the nearest match, starting with the class specified and searching up the
* hierarchy.
*
* @param clazz The class to search
* @param name The name of the field to search for
* @return The field found, or null if no field is found
*/
public static Field tryToFindDeclaredField(Class clazz, String name)
{
for (Class c = clazz; c != null && c != Object.class; c = c.getSuperclass())
{
try
{
return c.getDeclaredField(name);
}
catch (NoSuchFieldException e)
{
// No-op, we continue looking up the class hierarchy
}
}
return null;
}
/**
* Get all the declared methods on the class hierarchy. This will
* return overridden methods.
*
* @param clazz The class to search
* @return the set of all declared methods or an empty set if there are none
*/
public static Set getAllDeclaredMethods(Class clazz)
{
HashSet methods = new HashSet();
for (Class c = clazz; c != null && c != Object.class; c = c.getSuperclass())
{
Collections.addAll(methods, c.getDeclaredMethods());
}
return methods;
}
private static String buildInvokeMethodErrorMessage(Method method, Object obj, Object... args)
{
StringBuilder message = new StringBuilder(String.format(
"Details: Exception invoking method [%s] on object [%s], using arguments [", method.getName(), obj));
if (args != null)
{
for (int i = 0; i < args.length; i++)
{
message.append(i > 0 ? ", " : "").append(args[i]);
}
}
message.append("]");
return message.toString();
}
/**
*
* Invoke the method on the instance, with any arguments specified, casting
* the result of invoking the method to the expected return type.
*
*
*
* This method wraps {@link Method#invoke(Object, Object...)}, converting the
* checked exceptions that {@link Method#invoke(Object, Object...)} specifies
* to runtime exceptions.
*
*
*
* If instructed, this method attempts to set the accessible flag of the method in a
* {@link java.security.PrivilegedAction} before invoking the method.
*
*
* @param setAccessible flag indicating whether method should first be set as
* accessible
* @param method the method to invoke
* @param instance the instance to invoke the method
* @param args the arguments to the method
* @return the result of invoking the method, or null if the method's return
* type is void
* @throws RuntimeException if this Method object enforces Java
* language access control and the underlying method is
* inaccessible or if the underlying method throws an exception or
* if the initialization provoked by this method fails.
* @throws IllegalArgumentException if the method is an instance method and
* the specified instance argument is not an instance
* of the class or interface declaring the underlying method (or
* of a subclass or implementor thereof); if the number of actual
* and formal parameters differ; if an unwrapping conversion for
* primitive arguments fails; or if, after possible unwrapping, a
* parameter value cannot be converted to the corresponding formal
* parameter type by a method invocation conversion.
* @throws NullPointerException if the specified instance is
* null and the method is an instance method.
* @throws ClassCastException if the result of invoking the method cannot be
* cast to the expectedReturnType
* @throws ExceptionInInitializerError if the initialization provoked by this
* method fails.
* @see Method#invoke(Object, Object...)
*/
public static T invokeMethod(Object instance,
Method method, Class expectedReturnType,
boolean setAccessible,
Object... args) throws IllegalAccessException, IllegalArgumentException
{
if (setAccessible && !method.isAccessible())
{
if (System.getSecurityManager() != null)
{
AccessController.doPrivileged(new SetAccessiblePrivilegedAction(method));
}
else
{
method.setAccessible(true);
}
}
try
{
return expectedReturnType.cast(method.invoke(instance, args));
}
catch (InvocationTargetException e)
{
//re-visit DELTASPIKE-299 before changing this part
ExceptionUtils.throwAsRuntimeException(e.getCause());
//won't happen
return null;
}
catch (Exception e)
{
String customMessage = createCustomMessage(e, method, instance, args);
ExceptionUtils.changeAndThrowException(e, customMessage);
//won't happen
return null;
}
}
private static String createCustomMessage(Exception e, Method method, Object targetObject, Object... arguments)
{
return e.getMessage() + buildInvokeMethodErrorMessage(method, targetObject, arguments);
}
/**
* Extract the raw type, given a type.
*
* @param the type
* @param type the type to extract the raw type from
* @return the raw type, or null if the raw type cannot be determined.
*/
@SuppressWarnings("unchecked")
public static Class getRawType(Type type)
{
if (type instanceof Class)
{
return (Class) type;
}
else if (type instanceof ParameterizedType && ((ParameterizedType) type).getRawType() instanceof Class)
{
return (Class) ((ParameterizedType) type).getRawType();
}
return null;
}
/**
* Check if a class is serializable.
*
* @param clazz The class to check
* @return true if the class implements serializable or is a primitive (needed for type {@link Void}
*/
public static boolean isSerializable(Class clazz)
{
return clazz.isPrimitive() || Serializable.class.isAssignableFrom(clazz);
}
/**
* Checks if class is final
*
* @param clazz The class to check
* @return True if final, false otherwise
*/
public static boolean isFinal(Class clazz)
{
return Modifier.isFinal(clazz.getModifiers());
}
/**
* Checks if member is final
*
* @param member The member to check
* @return True if final, false otherwise
*/
public static boolean isFinal(Member member)
{
return Modifier.isFinal(member.getModifiers());
}
/**
* Checks if member is private
*
* @param member The member to check
* @return True if final, false otherwise
*/
public static boolean isPrivate(Member member)
{
return Modifier.isPrivate(member.getModifiers());
}
public static boolean isPackagePrivate(int mod)
{
return !(Modifier.isPrivate(mod) || Modifier.isProtected(mod) || Modifier.isPublic(mod));
}
/**
* Checks if type is static
*
* @param type Type to check
* @return True if static, false otherwise
*/
public static boolean isStatic(Class type)
{
return Modifier.isStatic(type.getModifiers());
}
/**
* Checks if member is static
*
* @param member Member to check
* @return True if static, false otherwise
*/
public static boolean isStatic(Member member)
{
return Modifier.isStatic(member.getModifiers());
}
public static boolean isTransient(Member member)
{
return Modifier.isTransient(member.getModifiers());
}
/**
* Checks if a method is abstract
*/
public static boolean isAbstract(Method method)
{
return Modifier.isAbstract(method.getModifiers());
}
/**
* Gets the actual type arguments of a class
*
* @param clazz The class to examine
* @return The type arguments
*/
public static Type[] getActualTypeArguments(Class clazz)
{
if (clazz == null)
{
throw new IllegalArgumentException("null isn't supported");
}
return clazz.getTypeParameters();
}
/**
* Gets the actual type arguments of a Type
*
* @param type The type to examine
* @return The type arguments
*/
public static Type[] getActualTypeArguments(Type type)
{
if (type instanceof Class)
{
return getActualTypeArguments((Class)type);
}
throw new IllegalArgumentException((type != null ? type.getClass().getName() : "null") + " isn't supported");
}
/**
* Checks if raw type is array type
*
* @param rawType The raw type to check
* @return True if array, false otherwise
*/
public static boolean isArrayType(Class rawType)
{
return rawType.isArray();
}
/**
* Checks if type is parameterized type
*
* @param type The type to check
* @return True if parameterized, false otherwise
*/
public static boolean isParameterizedType(Class type)
{
return type.getTypeParameters().length > 0;
}
public static boolean isParameterizedTypeWithWildcard(Class type)
{
if (isParameterizedType(type))
{
return containsWildcards(type.getTypeParameters());
}
else
{
return false;
}
}
private static boolean containsWildcards(Type[] types)
{
for (Type type : types)
{
if (type instanceof WildcardType)
{
return true;
}
}
return false;
}
public static boolean isPrimitive(Type type)
{
Class rawType = getRawType(type);
return rawType != null && rawType.isPrimitive();
}
}