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/*
* Copyright 2000-2013 Vaadin Ltd.
*
* Licensed 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 com.vaadin.util;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* An util class with helpers for reflection operations. Used internally by
* Vaadin and should not be used by application developers. Subject to change at
* any time.
*
* @since 6.2
*/
public class ReflectTools {
/**
* Locates the method in the given class. Returns null if the method is not
* found. Throws an ExceptionInInitializerError if there is a problem
* locating the method as this is mainly called from static blocks.
*
* @param cls
* Class that contains the method
* @param methodName
* The name of the method
* @param parameterTypes
* The parameter types for the method.
* @return A reference to the method
* @throws ExceptionInInitializerError
* Wraps any exception in an {@link ExceptionInInitializerError}
* so this method can be called from a static initializer.
*/
public static Method findMethod(Class<?> cls, String methodName,
Class<?>... parameterTypes) throws ExceptionInInitializerError {
try {
return cls.getDeclaredMethod(methodName, parameterTypes);
} catch (Exception e) {
throw new ExceptionInInitializerError(e);
}
}
/**
* Returns the value of the java field.
* <p>
* Uses getter if present, otherwise tries to access even private fields
* directly.
*
* @param object
* The object containing the field
* @param field
* The field we want to get the value for
* @return The value of the field in the object
* @throws InvocationTargetException
* If the value could not be retrieved
* @throws IllegalAccessException
* If the value could not be retrieved
* @throws IllegalArgumentException
* If the value could not be retrieved
*/
public static Object getJavaFieldValue(Object object,
java.lang.reflect.Field field) throws IllegalArgumentException,
IllegalAccessException, InvocationTargetException {
PropertyDescriptor pd;
try {
pd = new PropertyDescriptor(field.getName(), object.getClass());
Method getter = pd.getReadMethod();
if (getter != null) {
return getter.invoke(object, (Object[]) null);
}
} catch (IntrospectionException e1) {
// Ignore this and try to get directly using the field
}
// Try to get the value or throw an exception
if (!field.isAccessible()) {
// Try to gain access even if field is private
field.setAccessible(true);
}
return field.get(object);
}
/**
* Returns the value of the java field that is assignable to the property
* type.
* <p>
* Uses getter if a getter for the correct return type is present, otherwise
* tries to access even private fields directly. If the java field is not
* assignable to the property type throws an IllegalArgumentException.
*
* @param object
* The object containing the field
* @param field
* The field we want to get the value for
* @param propertyType
* The type the field must be assignable to
* @return The value of the field in the object
* @throws InvocationTargetException
* If the value could not be retrieved
* @throws IllegalAccessException
* If the value could not be retrieved
* @throws IllegalArgumentException
* If the value could not be retrieved
*/
public static Object getJavaFieldValue(Object object,
java.lang.reflect.Field field, Class<?> propertyType)
throws IllegalArgumentException, IllegalAccessException,
InvocationTargetException {
PropertyDescriptor pd;
try {
pd = new PropertyDescriptor(field.getName(), object.getClass());
if (propertyType.isAssignableFrom(pd.getPropertyType())) {
Method getter = pd.getReadMethod();
if (getter != null) {
return getter.invoke(object, (Object[]) null);
}
}
} catch (IntrospectionException e1) {
// Ignore this and try to get directly using the field
}
// If the field's type cannot be casted in to the requested type
if (!propertyType.isAssignableFrom(field.getType())) {
throw new IllegalArgumentException();
}
// Try to get the value or throw an exception
if (!field.isAccessible()) {
// Try to gain access even if field is private
field.setAccessible(true);
}
return field.get(object);
}
/**
* Sets the value of a java field.
* <p>
* Uses setter if present, otherwise tries to access even private fields
* directly.
*
* @param object
* The object containing the field
* @param field
* The field we want to set the value for
* @param value
* The value to set
* @throws IllegalAccessException
* If the value could not be assigned to the field
* @throws IllegalArgumentException
* If the value could not be assigned to the field
* @throws InvocationTargetException
* If the value could not be assigned to the field
*/
public static void setJavaFieldValue(Object object,
java.lang.reflect.Field field, Object value)
throws IllegalAccessException, IllegalArgumentException,
InvocationTargetException {
PropertyDescriptor pd;
try {
pd = new PropertyDescriptor(field.getName(), object.getClass());
Method setter = pd.getWriteMethod();
if (setter != null) {
// Exceptions are thrown forward if this fails
setter.invoke(object, value);
}
} catch (IntrospectionException e1) {
// Ignore this and try to set directly using the field
}
// Try to set the value directly to the field or throw an exception
if (!field.isAccessible()) {
// Try to gain access even if field is private
field.setAccessible(true);
}
field.set(object, value);
}
}
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