/*
* 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.wicket.spring;
import java.lang.ref.WeakReference;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.wicket.core.util.lang.WicketObjects;
import org.apache.wicket.proxy.IProxyTargetLocator;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.lang.Objects;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.AbstractApplicationContext;
import org.springframework.core.ResolvableType;
/**
* Implementation of {@link IProxyTargetLocator} that can locate beans within a spring application
* context. Beans are looked up by the combination of name and type, if name is omitted only type is
* used.
*
* @author Igor Vaynberg (ivaynberg)
* @author Istvan Devai
* @author Tobias Soloschenko
*/
public class SpringBeanLocator implements IProxyTargetLocator
{
private static final long serialVersionUID = 1L;
// Weak reference so we don't hold up WebApp classloader garbage collection.
private transient WeakReference<Class<?>> beanTypeCache;
private final String beanTypeName;
private String beanName;
private ISpringContextLocator springContextLocator;
private Boolean singletonCache = null;
/**
* Resolvable type for field to inject
*/
private ResolvableType fieldResolvableType;
/**
* If the field to inject is a list this is the resolvable type of its elements
*/
private ResolvableType fieldElementsResolvableType;
/**
* Constructor
*
* @param beanType
* bean class
* @param locator
* spring context locator
*/
public SpringBeanLocator(final Class<?> beanType, final ISpringContextLocator locator)
{
this(null, beanType, null, locator);
}
public SpringBeanLocator(final String beanName, final Class<?> beanType,
final ISpringContextLocator locator)
{
this(beanName, beanType, null, locator);
}
/**
* Constructor
*
* @param beanType
* bean class
* @param locator
* spring context locator
*/
public SpringBeanLocator(final Class<?> beanType, Field beanField,
final ISpringContextLocator locator)
{
this(null, beanType, beanField, locator);
}
/**
* Constructor
*
* @param beanName
* bean name
* @param beanType
* bean class
* @param locator
* spring context locator
*/
public SpringBeanLocator(final String beanName, final Class<?> beanType, Field beanField,
final ISpringContextLocator locator)
{
Args.notNull(locator, "locator");
Args.notNull(beanType, "beanType");
this.beanName = beanName;
beanTypeCache = new WeakReference<Class<?>>(beanType);
beanTypeName = beanType.getName();
springContextLocator = locator;
if (beanField != null)
{
fieldResolvableType = ResolvableType.forField(beanField);
fieldElementsResolvableType = extractElementGeneric(fieldResolvableType);
}
}
/**
* If the field type is a collection (Map, Set or List) extracts type
* information about its elements.
*
* @param fieldResolvableType
* the resolvable type of the field
* @return the resolvable type of elements of the field, if any.
*/
private ResolvableType extractElementGeneric(ResolvableType fieldResolvableType)
{
Class<?> clazz = fieldResolvableType.resolve();
if (Set.class.isAssignableFrom(clazz) || List.class.isAssignableFrom(clazz))
{
return fieldResolvableType.getGeneric();
}
else if (Map.class.isAssignableFrom(clazz))
{
return fieldResolvableType.getGeneric(1);
}
return null;
}
/**
* @return returns whether the bean (the locator is supposed to istantiate) is a singleton or
* not
*/
public boolean isSingletonBean()
{
if (singletonCache == null)
{
singletonCache = getBeanName() != null &&
getSpringContext().isSingleton(getBeanName());
}
return singletonCache;
}
/**
* @return bean class this locator is configured with
*/
public Class<?> getBeanType()
{
Class<?> clazz = beanTypeCache == null ? null : beanTypeCache.get();
if (clazz == null)
{
beanTypeCache = new WeakReference<>(
clazz = WicketObjects.resolveClass(beanTypeName));
if (clazz == null)
{
throw new RuntimeException("SpringBeanLocator could not find class [" +
beanTypeName + "] needed to locate the [" +
((beanName != null) ? (beanName) : ("bean name not specified")) + "] bean");
}
}
return clazz;
}
@Override
public Object locateProxyTarget()
{
final ApplicationContext context = getSpringContext();
return lookupSpringBean(context, beanName, getBeanType());
}
/**
*
* @return ApplicationContext
*/
private ApplicationContext getSpringContext()
{
final ApplicationContext context = springContextLocator.getSpringContext();
if (context == null)
{
throw new IllegalStateException("spring application context locator returned null");
}
return context;
}
/**
* @return bean name this locator is configured with
*/
public final String getBeanName()
{
return beanName;
}
/**
* @return context locator this locator is configured with
*/
public final ISpringContextLocator getSpringContextLocator()
{
return springContextLocator;
}
/**
* Looks up a bean by its name and class. Throws IllegalState exception if bean not found.
*
* @param ctx
* spring application context
*
* @param name
* bean name
* @param clazz
* bean class
* @throws java.lang.IllegalStateException
* @return found bean
*/
private Object lookupSpringBean(ApplicationContext ctx, String name, Class<?> clazz)
{
try
{
// If the name is set the lookup is clear
if (name != null)
{
return ctx.getBean(name, clazz);
}
// If the beanField information is null the clazz is going to be used
if (fieldResolvableType == null)
{
return ctx.getBean(clazz);
}
// If the given class is a list try to get the generic of the list
Class<?> lookupClass = fieldElementsResolvableType != null ?
fieldElementsResolvableType.resolve() : clazz;
// Else the lookup is done via Generic
List<String> names = loadBeanNames(ctx, lookupClass);
Object foundBeans = getBeansByName(ctx, names);
if(foundBeans != null)
{
return foundBeans;
}
throw new IllegalStateException(
"Concrete bean could not be received from the application context for class: " +
clazz.getName() + ".");
}
catch (NoSuchBeanDefinitionException e)
{
throw new IllegalStateException("bean with name [" + name + "] and class [" +
clazz.getName() + "] not found", e);
}
}
/**
* Returns a list of candidate names for the given class.
*
* @param ctx
* spring application context
* @param lookupClass
* the class to lookup
* @return a list of candidate names
*/
private List<String> loadBeanNames(ApplicationContext ctx, Class<?> lookupClass)
{
List<String> beanNames = new ArrayList<>();
Class<?> fieldType = getBeanType();
String[] beanNamesArr = ctx.getBeanNamesForType(fieldType);
//add names for field class
beanNames.addAll(Arrays.asList(beanNamesArr));
//add names for lookup class
if (lookupClass != fieldType)
{
beanNamesArr = ctx.getBeanNamesForType(lookupClass);
beanNames.addAll(Arrays.asList(beanNamesArr));
}
Iterator<String> nameIterator = beanNames.iterator();
//filter those beans who don't have a definition (used internally by Spring)
while (nameIterator.hasNext())
{
if (!ctx.containsBeanDefinition(nameIterator.next()))
{
nameIterator.remove();
}
}
return beanNames;
}
/**
* Retrieves a list of beans or a single bean for the given list of names and assignable to the
* current field to inject.
*
* @param ctx
* spring application context.
* @param names
* the list of candidate names
* @return a list of matching beans or a single one.
*/
private Object getBeansByName(ApplicationContext ctx, List<String> names)
{
FieldBeansCollector beansCollector = new FieldBeansCollector(fieldResolvableType);
for (String beanName : names)
{
RootBeanDefinition beanDef = getBeanDefinition(ctx, beanName);
if (beanDef == null)
{
continue;
}
ResolvableType candidateResolvableType = null;
//check if we have the class of the bean or the factory method.
//Usually if use XML as config file we have the class while we
//have the factory method if we use Java-based configuration.
if (beanDef.hasBeanClass())
{
candidateResolvableType = ResolvableType.forClass(beanDef.getBeanClass());
}
else if (beanDef.getResolvedFactoryMethod() != null)
{
candidateResolvableType = ResolvableType.forMethodReturnType(
beanDef.getResolvedFactoryMethod());
}
if (candidateResolvableType == null)
{
continue;
}
boolean exactMatch = fieldResolvableType.isAssignableFrom(candidateResolvableType);
boolean elementMatch = fieldElementsResolvableType != null && fieldElementsResolvableType.isAssignableFrom(candidateResolvableType);
if (exactMatch)
{
this.beanName = beanName;
return ctx.getBean(beanName);
}
if (elementMatch)
{
beansCollector.addBean(beanName, ctx.getBean(beanName));
}
}
return beansCollector.getBeansToInject();
}
@Override
public boolean equals(final Object obj)
{
if (obj instanceof SpringBeanLocator)
{
SpringBeanLocator other = (SpringBeanLocator)obj;
return beanTypeName.equals(other.beanTypeName) &&
Objects.equal(beanName, other.beanName);
}
return false;
}
@Override
public int hashCode()
{
int hashcode = beanTypeName.hashCode();
if (getBeanName() != null)
{
hashcode = hashcode + (127 * beanName.hashCode());
}
return hashcode;
}
/**
* Gets the root bean definition for the given name.
*
* @param ctx
* spring application context.
* @param name
* bean name
* @return bean definition for the current name, null if such a definition is not found.
*/
public RootBeanDefinition getBeanDefinition(final ApplicationContext ctx, final String name)
{
ConfigurableListableBeanFactory beanFactory = ((AbstractApplicationContext)ctx).getBeanFactory();
BeanDefinition beanDef = beanFactory.containsBean(name) ?
beanFactory.getMergedBeanDefinition(name) : null;
if (beanDef instanceof RootBeanDefinition)
{
return (RootBeanDefinition)beanDef;
}
return null;
}
}