org.springframework.context.expression.BeanFactoryAccessor Maven / Gradle / Ivy
/*
* Copyright 2002-2022 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
*
* https://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.context.expression;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.expression.AccessException;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.PropertyAccessor;
import org.springframework.expression.TypedValue;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* EL property accessor that knows how to traverse the beans of a
* Spring {@link org.springframework.beans.factory.BeanFactory}.
*
* @author Juergen Hoeller
* @author Andy Clement
* @since 3.0
*/
public class BeanFactoryAccessor implements PropertyAccessor {
@Override
public Class[] getSpecificTargetClasses() {
return new Class[] {BeanFactory.class};
}
@Override
public boolean canRead(EvaluationContext context, @Nullable Object target, String name) throws AccessException {
return (target instanceof BeanFactory beanFactory && beanFactory.containsBean(name));
}
@Override
public TypedValue read(EvaluationContext context, @Nullable Object target, String name) throws AccessException {
Assert.state(target instanceof BeanFactory, "Target must be of type BeanFactory");
return new TypedValue(((BeanFactory) target).getBean(name));
}
@Override
public boolean canWrite(EvaluationContext context, @Nullable Object target, String name) throws AccessException {
return false;
}
@Override
public void write(EvaluationContext context, @Nullable Object target, String name, @Nullable Object newValue)
throws AccessException {
throw new AccessException("Beans in a BeanFactory are read-only");
}
}