MapBasedDatabasePlatformSupport.java

/*
 * Copyright 2013-2014 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
 *
 *      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.springframework.cloud.aws.jdbc.datasource.support;

import org.springframework.util.Assert;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.Map;

/**
 * A map based implementation of the {@link DatabasePlatformSupport} interface. Sub classes must only provide map with
 * the database specific information. This class takes care of asserting and computing the returned information.
 *
 * @author Agim Emruli
 * @since 1.0
 */
public abstract class MapBasedDatabasePlatformSupport implements DatabasePlatformSupport {

    /**
     * Returns the driver class for the database platform.
     *
     * @param databaseType
     *         - The database type used to lookup the driver class name. Must not be null
     * @return - The driver class name, is never null
     * @throws IllegalArgumentException
     *         if there is not driver class name available for the DatabaseType
     */
    @Override
    public String getDriverClassNameForDatabase(DatabaseType databaseType) {
        Assert.notNull(databaseType, "databaseType must not be null");
        String candidate = this.getDriverClassNameMappings().get(databaseType);
        Assert.notNull(candidate, String.format("No driver class name found for database :'%s'", databaseType.name()));
        return candidate;
    }

    /**
     * Constructs the URL for the database by using a {@link URI} to construct the URL
     *
     * @param databaseType
     *         - The databaseType for which the URL should be constructed.
     * @param hostname
     *         - The hostname without any port information used to connect to.
     * @param port
     *         - The port used to connect to the database
     * @param databaseName
     *         - The database name used to connect to. The usage is implementation specific (e.g. for Oracle this is the SID)
     * @return - the database specific URL
     * @throws IllegalArgumentException
     *         if there is no scheme available for the database type or if the information is not valid to construct a URL.
     */
    @Override
    public String getDatabaseUrlForDatabase(DatabaseType databaseType, String hostname, int port, String databaseName) {
        String scheme = this.getSchemeNames().get(databaseType);
        String authenticationInfo = this.getAuthenticationInfo().get(databaseType);
        Assert.notNull(databaseType, String.format("No scheme name found for database :'%s'", databaseType.name()));
        try {
            return new URI(scheme, authenticationInfo, hostname, port, databaseName != null ? "/" + databaseName : null, null, null).toString();
        } catch (URISyntaxException e) {
            throw new IllegalArgumentException("Error constructing URI from Host:'" + hostname + "' and port:'" +
                    port + "' and database name:'" + databaseName + "'!");
        }
    }

    /**
     * Template method that must be implemented in order to retrieve all driver class names for every supported database
     * platform.
     *
     * @return Map containing the driver class name for every database platform
     */
    protected abstract Map<DatabaseType, String> getDriverClassNameMappings();


    /**
     * Template method that mus be implemented to get all scheme names for every supported database platform. Scheme
     * names are unfortunately only standardized in the root scheme (jdbc:) but not in the sub-scheme which is database
     * platform specific.
     *
     * @return Map containing the schema (and sub-scheme) names for every support database platform
     */
    protected abstract Map<DatabaseType, String> getSchemeNames();


    protected abstract Map<DatabaseType, String> getAuthenticationInfo();
}