Java tutorial
/* * Copyright 2002-2019 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 * * https://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.jdbc.support; import java.util.HashMap; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.lang.Nullable; /** * Registry for custom {@link org.springframework.jdbc.support.SQLExceptionTranslator} instances associated with * specific databases allowing for overriding translation based on values contained in the configuration file * named "sql-error-codes.xml". * * @author Thomas Risberg * @since 3.1.1 * @see SQLErrorCodesFactory */ public final class CustomSQLExceptionTranslatorRegistry { private static final Log logger = LogFactory.getLog(CustomSQLExceptionTranslatorRegistry.class); /** * Keep track of a single instance so we can return it to classes that request it. */ private static final CustomSQLExceptionTranslatorRegistry instance = new CustomSQLExceptionTranslatorRegistry(); /** * Return the singleton instance. */ public static CustomSQLExceptionTranslatorRegistry getInstance() { return instance; } /** * Map registry to hold custom translators specific databases. * Key is the database product name as defined in the * {@link org.springframework.jdbc.support.SQLErrorCodesFactory}. */ private final Map<String, SQLExceptionTranslator> translatorMap = new HashMap<>(); /** * Create a new instance of the {@link CustomSQLExceptionTranslatorRegistry} class. * <p>Not public to enforce Singleton design pattern. */ private CustomSQLExceptionTranslatorRegistry() { } /** * Register a new custom translator for the specified database name. * @param dbName the database name * @param translator the custom translator */ public void registerTranslator(String dbName, SQLExceptionTranslator translator) { SQLExceptionTranslator replaced = this.translatorMap.put(dbName, translator); if (logger.isDebugEnabled()) { if (replaced != null) { logger.debug("Replacing custom translator [" + replaced + "] for database '" + dbName + "' with [" + translator + "]"); } else { logger.debug("Adding custom translator of type [" + translator.getClass().getName() + "] for database '" + dbName + "'"); } } } /** * Find a custom translator for the specified database. * @param dbName the database name * @return the custom translator, or {@code null} if none found */ @Nullable public SQLExceptionTranslator findTranslatorForDatabase(String dbName) { return this.translatorMap.get(dbName); } }