org.springframework.beans.factory.config.PropertyPathFactoryBean Maven / Gradle / Ivy
/*
* Copyright 2002-2007 the original author or authors.
*
* 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 org.springframework.beans.factory.config;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.beans.BeansException;
import org.springframework.beans.FatalBeanException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.util.StringUtils;
/**
* {@link FactoryBean} that evaluates a property path on a given target object.
*
* The target object can be specified directly or via a bean name.
*
*
Usage examples:
*
*
<!-- target bean to be referenced by name -->
* <bean id="tb" class="org.springframework.beans.TestBean" singleton="false">
* <property name="age" value="10"/>
* <property name="spouse">
* <bean class="org.springframework.beans.TestBean">
* <property name="age" value="11"/>
* </bean>
* </property>
* </bean>
*
* <!-- will result in 12, which is the value of property 'age' of the inner bean -->
* <bean id="propertyPath1" class="org.springframework.beans.factory.config.PropertyPathFactoryBean">
* <property name="targetObject">
* <bean class="org.springframework.beans.TestBean">
* <property name="age" value="12"/>
* </bean>
* </property>
* <property name="propertyPath" value="age"/>
* </bean>
*
* <!-- will result in 11, which is the value of property 'spouse.age' of bean 'tb' -->
* <bean id="propertyPath2" class="org.springframework.beans.factory.config.PropertyPathFactoryBean">
* <property name="targetBeanName" value="tb"/>
* <property name="propertyPath" value="spouse.age"/>
* </bean>
*
* <!-- will result in 10, which is the value of property 'age' of bean 'tb' -->
* <bean id="tb.age" class="org.springframework.beans.factory.config.PropertyPathFactoryBean"/>
*
* If you are using Spring 2.0 and XML Schema support in your configuration file(s),
* you can also use the following style of configuration for property path access.
* (See also the appendix entitled 'XML Schema-based configuration' in the Spring
* reference manual for more examples.)
*
*
<!-- will result in 10, which is the value of property 'age' of bean 'tb' -->
* <util:property-path id="name" path="testBean.age"/>
*
* Thanks to Matthias Ernst for the suggestion and initial prototype!
*
* @author Juergen Hoeller
* @since 1.1.2
* @see #setTargetObject
* @see #setTargetBeanName
* @see #setPropertyPath
*/
public class PropertyPathFactoryBean implements FactoryBean, BeanNameAware, BeanFactoryAware {
private BeanWrapper targetBeanWrapper;
private String targetBeanName;
private String propertyPath;
private Class resultType;
private String beanName;
private BeanFactory beanFactory;
/**
* Specify a target object to apply the property path to.
* Alternatively, specify a target bean name.
* @param targetObject a target object, for example a bean reference
* or an inner bean
* @see #setTargetBeanName
*/
public void setTargetObject(Object targetObject) {
this.targetBeanWrapper = new BeanWrapperImpl(targetObject);
}
/**
* Specify the name of a target bean to apply the property path to.
* Alternatively, specify a target object directly.
* @param targetBeanName the bean name to be looked up in the
* containing bean factory (e.g. "testBean")
* @see #setTargetObject
*/
public void setTargetBeanName(String targetBeanName) {
this.targetBeanName = StringUtils.trimAllWhitespace(targetBeanName);
}
/**
* Specify the property path to apply to the target.
* @param propertyPath the property path, potentially nested
* (e.g. "age" or "spouse.age")
*/
public void setPropertyPath(String propertyPath) {
this.propertyPath = StringUtils.trimAllWhitespace(propertyPath);
}
/**
* Specify the type of the result from evaluating the property path.
* Note: This is not necessary for directly specified target objects
* or singleton target beans, where the type can be determined through
* introspection. Just specify this in case of a prototype target,
* provided that you need matching by type (for example, for autowiring).
* @param resultType the result type, for example "java.lang.Integer"
*/
public void setResultType(Class resultType) {
this.resultType = resultType;
}
/**
* The bean name of this PropertyPathFactoryBean will be interpreted
* as "beanName.property" pattern, if neither "targetObject" nor
* "targetBeanName" nor "propertyPath" have been specified.
* This allows for concise bean definitions with just an id/name.
*/
public void setBeanName(String beanName) {
this.beanName = StringUtils.trimAllWhitespace(BeanFactoryUtils.originalBeanName(beanName));
}
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
if (this.targetBeanWrapper != null && this.targetBeanName != null) {
throw new IllegalArgumentException("Specify either targetObject or targetBeanName, not both");
}
if (this.targetBeanWrapper == null && this.targetBeanName == null) {
if (this.propertyPath != null) {
throw new IllegalArgumentException(
"Specify targetObject or targetBeanName in combination with propertyPath");
}
// No other properties specified: check bean name.
int dotIndex = this.beanName.indexOf('.');
if (dotIndex == -1) {
throw new IllegalArgumentException(
"Neither targetObject nor targetBeanName specified, and PropertyPathFactoryBean " +
"bean name '" + this.beanName + "' does not follow 'beanName.property' syntax");
}
this.targetBeanName = this.beanName.substring(0, dotIndex);
this.propertyPath = this.beanName.substring(dotIndex + 1);
}
else if (this.propertyPath == null) {
// either targetObject or targetBeanName specified
throw new IllegalArgumentException("propertyPath is required");
}
if (this.targetBeanWrapper == null && this.beanFactory.isSingleton(this.targetBeanName)) {
// Eagerly fetch singleton target bean, and determine result type.
this.targetBeanWrapper = new BeanWrapperImpl(this.beanFactory.getBean(this.targetBeanName));
this.resultType = this.targetBeanWrapper.getPropertyType(this.propertyPath);
}
}
public Object getObject() throws BeansException {
BeanWrapper target = this.targetBeanWrapper;
if (target == null) {
// fetch prototype target bean
target = new BeanWrapperImpl(this.beanFactory.getBean(this.targetBeanName));
}
Object value = target.getPropertyValue(this.propertyPath);
if (value == null) {
throw new FatalBeanException("PropertyPathFactoryBean is not allowed to return null, " +
"but property value for path '" + this.propertyPath + "' is null");
}
return value;
}
public Class getObjectType() {
return this.resultType;
}
/**
* While this FactoryBean will often be used for singleton targets,
* the invoked getters for the property path might return a new object
* for each call, so we have to assume that we're not returning the
* same object for each getObject() call.
*/
public boolean isSingleton() {
return false;
}
}