/*
* Copyright 2002-2016 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.core.env;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.StringUtils;
/**
* Default implementation of the {@link PropertySources} interface.
* Allows manipulation of contained property sources and provides a constructor
* for copying an existing {@code PropertySources} instance.
*
* <p>Where <em>precedence</em> is mentioned in methods such as {@link #addFirst}
* and {@link #addLast}, this is with regard to the order in which property sources
* will be searched when resolving a given property with a {@link PropertyResolver}.
*
* @author Chris Beams
* @author Juergen Hoeller
* @since 3.1
* @see PropertySourcesPropertyResolver
*/
public class MutablePropertySources implements PropertySources {
private final Log logger;
private final List<PropertySource<?>> propertySourceList = new CopyOnWriteArrayList<>();
/**
* Create a new {@link MutablePropertySources} object.
*/
public MutablePropertySources() {
this.logger = LogFactory.getLog(getClass());
}
/**
* Create a new {@code MutablePropertySources} from the given propertySources
* object, preserving the original order of contained {@code PropertySource} objects.
*/
public MutablePropertySources(PropertySources propertySources) {
this();
for (PropertySource<?> propertySource : propertySources) {
addLast(propertySource);
}
}
/**
* Create a new {@link MutablePropertySources} object and inherit the given logger,
* usually from an enclosing {@link Environment}.
*/
MutablePropertySources(Log logger) {
this.logger = logger;
}
@Override
public boolean contains(String name) {
return this.propertySourceList.contains(PropertySource.named(name));
}
@Override
public PropertySource<?> get(String name) {
int index = this.propertySourceList.indexOf(PropertySource.named(name));
return (index != -1 ? this.propertySourceList.get(index) : null);
}
@Override
public Iterator<PropertySource<?>> iterator() {
return this.propertySourceList.iterator();
}
/**
* Add the given property source object with highest precedence.
*/
public void addFirst(PropertySource<?> propertySource) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Adding [%s] PropertySource with highest search precedence",
propertySource.getName()));
}
removeIfPresent(propertySource);
this.propertySourceList.add(0, propertySource);
}
/**
* Add the given property source object with lowest precedence.
*/
public void addLast(PropertySource<?> propertySource) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Adding [%s] PropertySource with lowest search precedence",
propertySource.getName()));
}
removeIfPresent(propertySource);
this.propertySourceList.add(propertySource);
}
/**
* Add the given property source object with precedence immediately higher
* than the named relative property source.
*/
public void addBefore(String relativePropertySourceName, PropertySource<?> propertySource) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Adding [%s] PropertySource with search precedence immediately higher than [%s]",
propertySource.getName(), relativePropertySourceName));
}
assertLegalRelativeAddition(relativePropertySourceName, propertySource);
removeIfPresent(propertySource);
int index = assertPresentAndGetIndex(relativePropertySourceName);
addAtIndex(index, propertySource);
}
/**
* Add the given property source object with precedence immediately lower
* than the named relative property source.
*/
public void addAfter(String relativePropertySourceName, PropertySource<?> propertySource) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Adding [%s] PropertySource with search precedence immediately lower than [%s]",
propertySource.getName(), relativePropertySourceName));
}
assertLegalRelativeAddition(relativePropertySourceName, propertySource);
removeIfPresent(propertySource);
int index = assertPresentAndGetIndex(relativePropertySourceName);
addAtIndex(index + 1, propertySource);
}
/**
* Return the precedence of the given property source, {@code -1} if not found.
*/
public int precedenceOf(PropertySource<?> propertySource) {
return this.propertySourceList.indexOf(propertySource);
}
/**
* Remove and return the property source with the given name, {@code null} if not found.
* @param name the name of the property source to find and remove
*/
public PropertySource<?> remove(String name) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Removing [%s] PropertySource", name));
}
int index = this.propertySourceList.indexOf(PropertySource.named(name));
return (index != -1 ? this.propertySourceList.remove(index) : null);
}
/**
* Replace the property source with the given name with the given property source object.
* @param name the name of the property source to find and replace
* @param propertySource the replacement property source
* @throws IllegalArgumentException if no property source with the given name is present
* @see #contains
*/
public void replace(String name, PropertySource<?> propertySource) {
if (logger.isDebugEnabled()) {
logger.debug(String.format("Replacing [%s] PropertySource with [%s]",
name, propertySource.getName()));
}
int index = assertPresentAndGetIndex(name);
this.propertySourceList.set(index, propertySource);
}
/**
* Return the number of {@link PropertySource} objects contained.
*/
public int size() {
return this.propertySourceList.size();
}
@Override
public String toString() {
String[] names = new String[this.size()];
for (int i = 0; i < size(); i++) {
names[i] = this.propertySourceList.get(i).getName();
}
return String.format("[%s]", StringUtils.arrayToCommaDelimitedString(names));
}
/**
* Ensure that the given property source is not being added relative to itself.
*/
protected void assertLegalRelativeAddition(String relativePropertySourceName, PropertySource<?> propertySource) {
String newPropertySourceName = propertySource.getName();
if (relativePropertySourceName.equals(newPropertySourceName)) {
throw new IllegalArgumentException(
String.format("PropertySource named [%s] cannot be added relative to itself", newPropertySourceName));
}
}
/**
* Remove the given property source if it is present.
*/
protected void removeIfPresent(PropertySource<?> propertySource) {
this.propertySourceList.remove(propertySource);
}
/**
* Add the given property source at a particular index in the list.
*/
private void addAtIndex(int index, PropertySource<?> propertySource) {
removeIfPresent(propertySource);
this.propertySourceList.add(index, propertySource);
}
/**
* Assert that the named property source is present and return its index.
* @param name the {@linkplain PropertySource#getName() name of the property source}
* to find
* @throws IllegalArgumentException if the named property source is not present
*/
private int assertPresentAndGetIndex(String name) {
int index = this.propertySourceList.indexOf(PropertySource.named(name));
if (index == -1) {
throw new IllegalArgumentException(String.format("PropertySource named [%s] does not exist", name));
}
return index;
}
}