ResourceBundleStringLookup.java
- /*
- * 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 {
- /**
- * Defines the singleton for this class.
- */
- static final ResourceBundleStringLookup INSTANCE = new ResourceBundleStringLookup();
- /**
- * The name of the resource bundle from which to look something up.
- */
- private final String bundleName;
- /**
- * Constructs a blank instance.
- */
- 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;
- }
- ResourceBundle getBundle(final String keyBundleName) {
- // The ResourceBundle class caches bundles, no need to cache here.
- return ResourceBundle.getBundle(keyBundleName);
- }
- String getString(final String keyBundleName, final String bundleKey) {
- return getBundle(keyBundleName).getString(bundleKey);
- }
- /**
- * 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);
- }
- 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 {
- return getString(keyBundleName, 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) {
- // Should only be a ClassCastException
- throw IllegalArgumentExceptions.format(e, "Error looking up resource bundle [%s] and key [%s].",
- keyBundleName, bundleKey);
- }
- }
- @Override
- public String toString() {
- return super.toString() + " [bundleName=" + bundleName + "]";
- }
- }