org.apache.commons.text.lookup.ResourceBundleStringLookup Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.text.lookup;
import java.util.ResourceBundle;
/**
* Looks up keys from resource bundles.
*
* Looks up the value for a given key in the format "BundleName:BundleKey".
*
*
* For example: "com.domain.messages:MyKey".
*
*
* @see ResourceBundle
* @since 1.3
*/
final class ResourceBundleStringLookup extends AbstractStringLookup {
/**
* The name of the resource bundle from which to look something up.
*/
private final String bundleName;
/**
* Defines the singleton for this class.
*/
static final ResourceBundleStringLookup INSTANCE = new ResourceBundleStringLookup();
/**
* No need to build instances for now.
*/
private ResourceBundleStringLookup() {
this(null);
}
/**
* Constructs an instance that only works for the given bundle.
*
* @param bundleName
* the name of the resource bundle from which we will look keys up.
* @since 1.5
*/
ResourceBundleStringLookup(final String bundleName) {
this.bundleName = bundleName;
}
/**
* Looks up the value for the key in the format "BundleName:BundleKey".
*
* For example: "com.domain.messages:MyKey".
*
* @param key
* the key to be looked up, may be null
* @return The value associated with the key.
* @see ResourceBundle
* @see ResourceBundle#getBundle(String)
* @see ResourceBundle#getString(String)
*/
@Override
public String lookup(final String key) {
if (key == null) {
return null;
}
final String[] keys = key.split(SPLIT_STR);
final int keyLen = keys.length;
final boolean anyBundle = bundleName == null;
if (anyBundle && keyLen != 2) {
throw IllegalArgumentExceptions
.format("Bad resource bundle key format [%s]; expected format is BundleName:KeyName.", key);
} else if (bundleName != null && keyLen != 1) {
throw IllegalArgumentExceptions.format("Bad resource bundle key format [%s]; expected format is KeyName.",
key);
}
final String keyBundleName = anyBundle ? keys[0] : bundleName;
final String bundleKey = anyBundle ? keys[1] : keys[0];
try {
// The ResourceBundle class caches bundles, no need to cache here.
return ResourceBundle.getBundle(keyBundleName).getString(bundleKey);
} catch (final Exception e) {
throw IllegalArgumentExceptions.format(e, "Error looking up resource bundle [%s] and key [%s].",
keyBundleName, bundleKey);
}
}
}