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/*
* Copyright 2000-2014 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.data.util;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
/**
* Utility class for Java Beans information access.
*
* @author Vaadin Ltd
*/
public final class BeanUtil implements Serializable {
// Prevent instantiation of util class
private BeanUtil() {
}
/**
* Returns the property descriptors of a class or an interface.
*
* For an interface, superinterfaces are also iterated as Introspector does
* not take them into account (Oracle Java bug 4275879), but in that case,
* both the setter and the getter for a property must be in the same
* interface and should not be overridden in subinterfaces for the discovery
* to work correctly.
*
* NOTE : This utility method relies on introspection (and returns
* PropertyDescriptor) which is a part of java.beans package. The latter
* package could require bigger JDK in the future (with Java 9+). So it may
* be changed in the future.
*
* For interfaces, the iteration is depth first and the properties of
* superinterfaces are returned before those of their subinterfaces.
*
* @param beanClass
* @return
* @throws IntrospectionException
*/
public static List<PropertyDescriptor> getBeanPropertyDescriptor(
final Class<?> beanClass) throws IntrospectionException {
// Oracle bug 4275879: Introspector does not consider superinterfaces of
// an interface
if (beanClass.isInterface()) {
List<PropertyDescriptor> propertyDescriptors = new ArrayList<PropertyDescriptor>();
for (Class<?> cls : beanClass.getInterfaces()) {
propertyDescriptors.addAll(getBeanPropertyDescriptor(cls));
}
BeanInfo info = Introspector.getBeanInfo(beanClass);
propertyDescriptors.addAll(getPropertyDescriptors(info));
return propertyDescriptors;
} else {
BeanInfo info = Introspector.getBeanInfo(beanClass);
return getPropertyDescriptors(info);
}
}
/**
* Returns {@code propertyId} class for property declared in {@code clazz}.
* Property could be of form "property.subProperty[.subProperty2]" i.e.
* refer to some nested property.
*
* @param clazz
* class where property is declared
* @param propertyId
* property of form "property" or
* "property.subProperty[.subProperty2]"
* @return class of the property
* @throws IntrospectionException
*/
public static Class<?> getPropertyType(Class<?> clazz, String propertyId)
throws IntrospectionException {
if (propertyId.contains(".")) {
String[] parts = propertyId.split("\\.", 2);
// Get the type of the field in the "cls" class
Class<?> propertyBean = getPropertyType(clazz, parts[0]);
// Find the rest from the sub type
return getPropertyType(propertyBean, parts[1]);
} else {
List<PropertyDescriptor> descriptors = getBeanPropertyDescriptor(clazz);
for (PropertyDescriptor descriptor : descriptors) {
final Method getMethod = descriptor.getReadMethod();
if (descriptor.getName().equals(propertyId)
&& getMethod != null
&& getMethod.getDeclaringClass() != Object.class) {
return descriptor.getPropertyType();
}
}
return null;
}
}
// Workaround for Java6 bug JDK-6788525. Do nothing for JDK7+.
private static List<PropertyDescriptor> getPropertyDescriptors(
BeanInfo beanInfo) {
PropertyDescriptor[] descriptors = beanInfo.getPropertyDescriptors();
List<PropertyDescriptor> result = new ArrayList<PropertyDescriptor>(
descriptors.length);
for (PropertyDescriptor descriptor : descriptors) {
try {
Method readMethod = getMethodFromBridge(descriptor
.getReadMethod());
if (readMethod != null) {
Method writeMethod = getMethodFromBridge(
descriptor.getWriteMethod(),
readMethod.getReturnType());
if (writeMethod == null) {
writeMethod = descriptor.getWriteMethod();
}
PropertyDescriptor descr = new PropertyDescriptor(
descriptor.getName(), readMethod, writeMethod);
result.add(descr);
} else {
result.add(descriptor);
}
} catch (SecurityException ignore) {
// handle next descriptor
} catch (IntrospectionException e) {
result.add(descriptor);
}
}
return result;
}
/**
* Return declared method for which {@code bridgeMethod} is generated. If
* {@code bridgeMethod} is not a bridge method then return null.
*/
private static Method getMethodFromBridge(Method bridgeMethod)
throws SecurityException {
if (bridgeMethod == null) {
return null;
}
return getMethodFromBridge(bridgeMethod,
bridgeMethod.getParameterTypes());
}
/**
* Return declared method for which {@code bridgeMethod} is generated using
* its {@code paramTypes}. If {@code bridgeMethod} is not a bridge method
* then return null.
*/
private static Method getMethodFromBridge(Method bridgeMethod,
Class<?>... paramTypes) throws SecurityException {
if (bridgeMethod == null || !bridgeMethod.isBridge()) {
return null;
}
try {
return bridgeMethod.getDeclaringClass().getMethod(
bridgeMethod.getName(), paramTypes);
} catch (NoSuchMethodException e) {
return null;
}
}
}
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