| /* |
| * 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.MissingResourceException; |
| import java.util.ResourceBundle; |
| |
| /** |
| * Looks up keys from resource bundles. |
| * <p> |
| * Looks up the value for a given key in the format "BundleName:BundleKey". |
| * </p> |
| * <p> |
| * For example: "com.domain.messages:MyKey". |
| * </p> |
| * |
| * @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 MissingResourceException e) { |
| // The key is missing, return null such that an interpolator can supply a default value. |
| return null; |
| } catch (final Exception e) { |
| throw IllegalArgumentExceptions.format(e, "Error looking up resource bundle [%s] and key [%s].", |
| keyBundleName, bundleKey); |
| } |
| } |
| |
| } |