/*
* Copyright 2002-2008 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.io.support;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Properties;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.io.Resource;
import org.springframework.util.CollectionUtils;
import org.springframework.util.DefaultPropertiesPersister;
import org.springframework.util.PropertiesPersister;
/**
* Base class for JavaBean-style components that need to load properties
* from one or more resources. Supports local properties as well, with
* configurable overriding.
*
* @author Juergen Hoeller
* @since 1.2.2
*/
public abstract class PropertiesLoaderSupport {
public static final String XML_FILE_EXTENSION = ".xml";
/** Logger available to subclasses */
protected final Log logger = LogFactory.getLog(getClass());
private Properties[] localProperties;
private Resource[] locations;
private boolean localOverride = false;
private boolean ignoreResourceNotFound = false;
private String fileEncoding;
private PropertiesPersister propertiesPersister = new DefaultPropertiesPersister();
/**
* Set local properties, e.g. via the "props" tag in XML bean definitions.
* These can be considered defaults, to be overridden by properties
* loaded from files.
*/
public void setProperties(Properties properties) {
this.localProperties = new Properties[] {properties};
}
/**
* Set local properties, e.g. via the "props" tag in XML bean definitions,
* allowing for merging multiple properties sets into one.
*/
public void setPropertiesArray(Properties[] propertiesArray) {
this.localProperties = propertiesArray;
}
/**
* Set a location of a properties file to be loaded.
* <p>Can point to a classic properties file or to an XML file
* that follows JDK 1.5's properties XML format.
*/
public void setLocation(Resource location) {
this.locations = new Resource[] {location};
}
/**
* Set locations of properties files to be loaded.
* <p>Can point to classic properties files or to XML files
* that follow JDK 1.5's properties XML format.
* <p>Note: Properties defined in later files will override
* properties defined earlier files, in case of overlapping keys.
* Hence, make sure that the most specific files are the last
* ones in the given list of locations.
*/
public void setLocations(Resource[] locations) {
this.locations = locations;
}
/**
* Set whether local properties override properties from files.
* <p>Default is "false": Properties from files override local defaults.
* Can be switched to "true" to let local properties override defaults
* from files.
*/
public void setLocalOverride(boolean localOverride) {
this.localOverride = localOverride;
}
/**
* Set if failure to find the property resource should be ignored.
* <p>"true" is appropriate if the properties file is completely optional.
* Default is "false".
*/
public void setIgnoreResourceNotFound(boolean ignoreResourceNotFound) {
this.ignoreResourceNotFound = ignoreResourceNotFound;
}
/**
* Set the encoding to use for parsing properties files.
* <p>Default is none, using the <code>java.util.Properties</code>
* default encoding.
* <p>Only applies to classic properties files, not to XML files.
* @see org.springframework.util.PropertiesPersister#load
*/
public void setFileEncoding(String encoding) {
this.fileEncoding = encoding;
}
/**
* Set the PropertiesPersister to use for parsing properties files.
* The default is DefaultPropertiesPersister.
* @see org.springframework.util.DefaultPropertiesPersister
*/
public void setPropertiesPersister(PropertiesPersister propertiesPersister) {
this.propertiesPersister =
(propertiesPersister != null ? propertiesPersister : new DefaultPropertiesPersister());
}
/**
* Return a merged Properties instance containing both the
* loaded properties and properties set on this FactoryBean.
*/
protected Properties mergeProperties() throws IOException {
Properties result = new Properties();
if (this.localOverride) {
// Load properties from file upfront, to let local properties override.
loadProperties(result);
}
if (this.localProperties != null) {
for (int i = 0; i < this.localProperties.length; i++) {
CollectionUtils.mergePropertiesIntoMap(this.localProperties[i], result);
}
}
if (!this.localOverride) {
// Load properties from file afterwards, to let those properties override.
loadProperties(result);
}
return result;
}
/**
* Load properties into the given instance.
* @param props the Properties instance to load into
* @throws java.io.IOException in case of I/O errors
* @see #setLocations
*/
protected void loadProperties(Properties props) throws IOException {
if (this.locations != null) {
for (int i = 0; i < this.locations.length; i++) {
Resource location = this.locations[i];
if (logger.isInfoEnabled()) {
logger.info("Loading properties file from " + location);
}
InputStream is = null;
try {
is = location.getInputStream();
if (location.getFilename().endsWith(XML_FILE_EXTENSION)) {
this.propertiesPersister.loadFromXml(props, is);
}
else {
if (this.fileEncoding != null) {
this.propertiesPersister.load(props, new InputStreamReader(is, this.fileEncoding));
}
else {
this.propertiesPersister.load(props, is);
}
}
}
catch (IOException ex) {
if (this.ignoreResourceNotFound) {
if (logger.isWarnEnabled()) {
logger.warn("Could not load properties from " + location + ": " + ex.getMessage());
}
}
else {
throw ex;
}
}
finally {
if (is != null) {
is.close();
}
}
}
}
}
}