/**
* Copyright 2009 by dueni.ch
*
* 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 ch.dueni.util;
import java.io.File;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.ResourceBundle;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* <code>MultiplePropertiesResourceBundle</code> is an abstract base implementation to allow to
* combine a ResourceBundle from multiple properties files whereas these properties files must end
* with the same name - the base-name for these combined ResourceBundle.
* <p>
* A concrete implementation must subclass this class and provide a default constructor in which
* <code>super("base-name");</code> or <code>super("package.name","base-name");</code> must be
* called depending on if your properties files are located in default or a specific package.
* </p>
*
* <pre>
* public class ExampleResourceBundle extends MultiplePropertiesResourceBundle {
* public ExampleResourceBundle() {
* super("example");
* }
* }
*
* or
*
* public class ExampleResourceBundle extends MultiplePropertiesResourceBundle {
* public ExampleResourceBundle() {
* super("my.package", "example");
* }
* }
* </pre>
*
* <p>
* For each Locale that you need to support you also must provide Locale variants of your java
* ResourceBindle class as shown below. Creating an empty subclass of the above class does the job -
* the separate class is needed to let {@link ResourceBundle#getBundle(String, Locale)} find and
* cache your bundle with the right Locale.
* </p>
*
* <pre>
* public class ExampleResourceBundle_de extends ExampleResourceBundle {
* }
* </pre>
*
* <h3>File name rules</h3>
* <p>
* To allow automatic detection of the multiple properties files, for each filename you must provide
* a general properties file without any Locale extension in the name (e.g.
* additional-example.properties as a variant to examples.properties) - otherwise that properties
* file name will not be used to load as PropertyResourceBundle. Let's assume we used the base-name
* "example" and the following list of properties files are reachable:
* </p>
* <ul>
* <li>example.properties</li>
* <li>example_de.properties</li>
* <li>example_en.properties</li>
* <li>additional-example.properties</li>
* <li>additional-example_en.properties</li>
* <li>another-example_de.properties</li>
* </ul>
* <p>
* Only <i>example</i> and <i>additional-example</i> will be used as base-names to load this
* <code>MultiplePropertiesResourceBundle</code> - <i>another-example.properties</i> is missing
* and therefore <i>another-example</i> is not detected as a valid base-name.
* </p>
* <p>
* It is also supported to provide additional properties files with a jar file. To make sure that
* jar file is recognized as properties file provider it must contain a file "base-name".properties
* (e.g. example.properties). This marker file may be empty and is only used to find all resource
* paths containing properties files of interest (with matching base-name). In fact, every path
* location containing properties files to be combined into one MultiplePropertiesResourceBundle
* must contain that "base-name".properties file.
* </p>
* <p>
* The load order of the properties files is base-named file first and then the additional
* properties files in natural sort order of the file name. Properties files loaded later may
* override previously loaded properties.
* </p>
*
* @author Hanspeter Dünnenberger
*/
public abstract class MultiplePropertiesResourceBundle extends ResourceBundle {
private static final String CLASS = MultiplePropertiesResourceBundle.class.getName();
/** private Logger instance */
private static final Logger LOG = Logger.getLogger(CLASS);
/**
* The base name for the ResourceBundles to load in.
*/
private String baseName;
/**
* The package name where the properties files should be.
*/
private String packageName;
/**
* A Map containing the combined resources of all parts building this
* MultiplePropertiesResourceBundle.
*/
private Map<String, Object> combined;
/**
* Construct a <code>MultiplePropertiesResourceBundle</code> for the passed in base-name.
*
* @param baseName
* the base-name that must be part of the properties file names.
*/
protected MultiplePropertiesResourceBundle(String baseName) {
this(null, baseName);
}
/**
* Construct a <code>MultiplePropertiesResourceBundle</code> for the passed in base-name.
*
* @param packageName
* the package name where the properties files should be.
* @param baseName
* the base-name that must be part of the properties file names.
*/
protected MultiplePropertiesResourceBundle(String packageName, String baseName) {
this.packageName = packageName;
this.baseName = baseName;
}
@Override
public Object handleGetObject(String key) {
if (key == null) {
throw new NullPointerException();
}
loadBundlesOnce();
return combined.get(key);
}
@Override
public Enumeration<String> getKeys() {
loadBundlesOnce();
ResourceBundle parent = this.parent;
return new ResourceBundleEnumeration(combined.keySet(), (parent != null) ? parent.getKeys()
: null);
}
/**
* Load the resources once.
*/
private void loadBundlesOnce() {
if (combined == null) {
combined = new HashMap<String, Object>(128);
List<String> bundleNames = findBaseNames(baseName);
for (String bundleName : bundleNames) {
ResourceBundle bundle = ResourceBundle.getBundle(bundleName, getLocale());
Enumeration<String> keys = bundle.getKeys();
String key = null;
while (keys.hasMoreElements()) {
key = keys.nextElement();
combined.put(key, bundle.getObject(key));
}
}
}
}
/**
* Return a Set with the real base-names of the multiple properties based resource bundles that
* contribute to the full set of resources.
*
* @param baseName
* the base-name that must be part of the properties file names.
* @return a List with the real base-names.
*/
private List<String> findBaseNames(final String baseName) {
final String METHOD = "findBaseNames";
boolean isLoggable = LOG.isLoggable(Level.FINE);
ClassLoader cl = Thread.currentThread().getContextClassLoader();
List<String> bundleNames = new ArrayList<String>();
try {
String baseFileName = baseName + ".properties";
String resourcePath = getResourcePath();
String resourceName = resourcePath + baseFileName;
if (isLoggable) {
LOG.logp(Level.FINE, CLASS, METHOD, "Looking for files named '" + resourceName + "'");
}
Enumeration<URL> names = cl.getResources(resourceName);
while (names.hasMoreElements()) {
URL jarUrl = names.nextElement();
if (isLoggable) {
LOG.logp(Level.FINE, CLASS, METHOD, "inspecting: " + jarUrl);
}
if ("jar".equals(jarUrl.getProtocol())) {
String path = jarUrl.getFile();
String filename = path.substring(0, path.length() - resourceName.length() - 2);
if (filename.startsWith("file:")) {
filename = filename.substring(5);
}
JarFile jar = new JarFile(filename);
for (Enumeration<JarEntry> entries = jar.entries(); entries.hasMoreElements();) {
JarEntry entry = entries.nextElement();
String name = entry.getName();
addMatchingNameOnce("", baseName, bundleNames, baseFileName, name);
}
jar.close();
} else {
File dir = new File(jarUrl.getFile());
dir = dir.getParentFile();
if (dir.isDirectory()) {
for (String name : dir.list()) {
addMatchingNameOnce(resourcePath, baseName, bundleNames, baseFileName, name);
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
Collections.sort(bundleNames, new Comparator<String>() {
public int compare(String o1, String o2) {
int rc = 0;
if (baseName.equals(o1)) {
rc = -1;
} else if (baseName.equals(o2)) {
rc = 1;
} else {
rc = o1.compareTo(o2);
}
return rc;
}
});
if (isLoggable) {
LOG.logp(Level.FINE, CLASS, METHOD, "Combine ResourceBundles named: " + bundleNames);
}
return bundleNames;
}
private String getResourcePath() {
String result = "";
if (packageName != null) {
result = packageName.replaceAll("\\.", "/") + "/";
}
return result;
}
private void addMatchingNameOnce(String resourcePath, String baseName, List<String> bundleNames,
String baseFileName, String name) {
int prefixed = name.indexOf(baseName);
if (prefixed > -1 && name.endsWith(baseFileName)) {
String toAdd = resourcePath + name.substring(0, prefixed) + baseName;
if (!bundleNames.contains(toAdd)) {
bundleNames.add(toAdd);
}
}
}
}