org.springframework.beans.factory.config.BeanDefinitionVisitor 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 java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValue;
import org.springframework.util.ObjectUtils;
/**
* Visitor base class for traversing {@link BeanDefinition} objects, in particular
* the property values and constructor argument values contained in them.
*
* The abstract {@link #resolveStringValue} method has to be implemented
* in concrete subclasses, following arbitrary resolution strategies.
*
*
Used by {@link PropertyPlaceholderConfigurer} to parse all String values
* contained in a BeanDefinition, resolving any placeholders found.
*
* @author Juergen Hoeller
* @since 1.2
* @see BeanDefinition
* @see BeanDefinition#getPropertyValues
* @see BeanDefinition#getConstructorArgumentValues
* @see #resolveStringValue(String)
* @see PropertyPlaceholderConfigurer
*/
public abstract class BeanDefinitionVisitor {
/**
* Traverse the given BeanDefinition object and the MutablePropertyValues
* and ConstructorArgumentValues contained in them.
* @param beanDefinition the BeanDefinition object to traverse
* @see #resolveStringValue(String)
*/
public void visitBeanDefinition(BeanDefinition beanDefinition) {
visitBeanClassName(beanDefinition);
visitScope(beanDefinition);
visitPropertyValues(beanDefinition.getPropertyValues());
ConstructorArgumentValues cas = beanDefinition.getConstructorArgumentValues();
visitIndexedArgumentValues(cas.getIndexedArgumentValues());
visitGenericArgumentValues(cas.getGenericArgumentValues());
}
protected void visitBeanClassName(BeanDefinition beanDefinition) {
String beanClassName = beanDefinition.getBeanClassName();
if (beanClassName != null) {
String resolvedName = resolveStringValue(beanClassName);
if (!beanClassName.equals(resolvedName)) {
beanDefinition.setBeanClassName(resolvedName);
}
}
}
protected void visitScope(BeanDefinition beanDefinition) {
String scope = beanDefinition.getScope();
if (scope != null) {
String resolvedScope = resolveStringValue(scope);
if (!scope.equals(resolvedScope)) {
beanDefinition.setScope(resolvedScope);
}
}
}
protected void visitPropertyValues(MutablePropertyValues pvs) {
PropertyValue[] pvArray = pvs.getPropertyValues();
for (int i = 0; i < pvArray.length; i++) {
PropertyValue pv = pvArray[i];
Object newVal = resolveValue(pv.getValue());
if (!ObjectUtils.nullSafeEquals(newVal, pv.getValue())) {
pvs.addPropertyValue(pv.getName(), newVal);
}
}
}
protected void visitIndexedArgumentValues(Map ias) {
for (Iterator it = ias.values().iterator(); it.hasNext();) {
ConstructorArgumentValues.ValueHolder valueHolder =
(ConstructorArgumentValues.ValueHolder) it.next();
Object newVal = resolveValue(valueHolder.getValue());
if (!ObjectUtils.nullSafeEquals(newVal, valueHolder.getValue())) {
valueHolder.setValue(newVal);
}
}
}
protected void visitGenericArgumentValues(List gas) {
for (Iterator it = gas.iterator(); it.hasNext();) {
ConstructorArgumentValues.ValueHolder valueHolder =
(ConstructorArgumentValues.ValueHolder) it.next();
Object newVal = resolveValue(valueHolder.getValue());
if (!ObjectUtils.nullSafeEquals(newVal, valueHolder.getValue())) {
valueHolder.setValue(newVal);
}
}
}
protected Object resolveValue(Object value) {
if (value instanceof BeanDefinition) {
visitBeanDefinition((BeanDefinition) value);
}
else if (value instanceof BeanDefinitionHolder) {
visitBeanDefinition(((BeanDefinitionHolder) value).getBeanDefinition());
}
else if (value instanceof RuntimeBeanReference) {
RuntimeBeanReference ref = (RuntimeBeanReference) value;
String newBeanName = resolveStringValue(ref.getBeanName());
if (!newBeanName.equals(ref.getBeanName())) {
return new RuntimeBeanReference(newBeanName);
}
}
else if (value instanceof List) {
visitList((List) value);
}
else if (value instanceof Set) {
visitSet((Set) value);
}
else if (value instanceof Map) {
visitMap((Map) value);
}
else if (value instanceof TypedStringValue) {
TypedStringValue typedStringValue = (TypedStringValue) value;
String stringValue = typedStringValue.getValue();
if (stringValue != null) {
String visitedString = resolveStringValue(stringValue);
typedStringValue.setValue(visitedString);
}
}
else if (value instanceof String) {
return resolveStringValue((String) value);
}
return value;
}
protected void visitList(List listVal) {
for (int i = 0; i < listVal.size(); i++) {
Object elem = listVal.get(i);
Object newVal = resolveValue(elem);
if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
listVal.set(i, newVal);
}
}
}
protected void visitSet(Set setVal) {
for (Iterator it = new HashSet(setVal).iterator(); it.hasNext();) {
Object elem = it.next();
Object newVal = resolveValue(elem);
if (!ObjectUtils.nullSafeEquals(newVal, elem)) {
setVal.remove(elem);
setVal.add(newVal);
}
}
}
protected void visitMap(Map mapVal) {
for (Iterator it = new HashMap(mapVal).entrySet().iterator(); it.hasNext();) {
Map.Entry entry = (Map.Entry) it.next();
Object key = entry.getKey();
Object newKey = resolveValue(key);
boolean isNewKey = !ObjectUtils.nullSafeEquals(key, newKey);
Object val = entry.getValue();
Object newVal = resolveValue(val);
if (isNewKey) {
mapVal.remove(key);
}
if (isNewKey || !ObjectUtils.nullSafeEquals(newVal, val)) {
mapVal.put(newKey, newVal);
}
}
}
/**
* Resolve the given String value, for example parsing placeholders.
* @param strVal the original String value
* @return the resolved String value
*/
protected abstract String resolveStringValue(String strVal);
}