1.1 --- a/src/java/de/uapcore/lightpit/DatabaseFacade.java Sun Apr 08 16:51:15 2018 +0200
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,178 +0,0 @@
1.4 -/*
1.5 - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
1.6 - *
1.7 - * Copyright 2018 Mike Becker. All rights reserved.
1.8 - *
1.9 - * Redistribution and use in source and binary forms, with or without
1.10 - * modification, are permitted provided that the following conditions are met:
1.11 - *
1.12 - * 1. Redistributions of source code must retain the above copyright
1.13 - * notice, this list of conditions and the following disclaimer.
1.14 - *
1.15 - * 2. Redistributions in binary form must reproduce the above copyright
1.16 - * notice, this list of conditions and the following disclaimer in the
1.17 - * documentation and/or other materials provided with the distribution.
1.18 - *
1.19 - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.20 - * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.21 - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.22 - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
1.23 - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.24 - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.25 - * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.26 - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.27 - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.28 - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.29 - * POSSIBILITY OF SUCH DAMAGE.
1.30 - *
1.31 - */
1.32 -package de.uapcore.lightpit;
1.33 -
1.34 -import java.sql.Connection;
1.35 -import java.sql.DatabaseMetaData;
1.36 -import java.sql.SQLException;
1.37 -import java.util.Optional;
1.38 -import javax.naming.Context;
1.39 -import javax.naming.InitialContext;
1.40 -import javax.naming.NamingException;
1.41 -import javax.servlet.ServletContext;
1.42 -import javax.servlet.ServletContextEvent;
1.43 -import javax.servlet.ServletContextListener;
1.44 -import javax.servlet.annotation.WebListener;
1.45 -import javax.sql.DataSource;
1.46 -import org.slf4j.Logger;
1.47 -import org.slf4j.LoggerFactory;
1.48 -
1.49 -/**
1.50 - * Provides access to different privilege layers within the database.
1.51 - */
1.52 -@WebListener
1.53 -public final class DatabaseFacade implements ServletContextListener {
1.54 -
1.55 - private static final Logger LOG = LoggerFactory.getLogger(DatabaseFacade.class);
1.56 -
1.57 - /**
1.58 - * Timeout in seconds for the validation test.
1.59 - */
1.60 - private static final int DB_TEST_TIMEOUT = 10;
1.61 -
1.62 - public static enum Dialect {
1.63 - Postgres;
1.64 - }
1.65 -
1.66 - /**
1.67 - * The database dialect to use.
1.68 - *
1.69 - * May be override by context parameter.
1.70 - *
1.71 - * @see Constants#CTX_ATTR_DB_DIALECT
1.72 - */
1.73 - private Dialect dialect = Dialect.Postgres;
1.74 -
1.75 - /**
1.76 - * The default schema to test against when validating the connection.
1.77 - *
1.78 - * May be overridden by context parameter.
1.79 - *
1.80 - * @see Constants#CTX_ATTR_DB_SCHEMA
1.81 - */
1.82 - private static final String DB_DEFAULT_SCHEMA = "lightpit";
1.83 -
1.84 - /**
1.85 - * The attribute name in the Servlet context under which an instance of this class can be found.
1.86 - */
1.87 - public static final String SC_ATTR_NAME = DatabaseFacade.class.getName();
1.88 - private ServletContext sc;
1.89 -
1.90 - private static final String DS_JNDI_NAME = "jdbc/lightpit/app";
1.91 - private Optional<DataSource> dataSource;
1.92 -
1.93 - /**
1.94 - * Returns the data source.
1.95 - *
1.96 - * The Optional returned should never be empty. However, if something goes
1.97 - * wrong during initialization, the data source might be absent.
1.98 - * Hence, users of this data source are forced to check the existence.
1.99 - *
1.100 - * @return a data source
1.101 - */
1.102 - public Optional<DataSource> getDataSource() {
1.103 - return dataSource;
1.104 - }
1.105 -
1.106 - public Dialect getSQLDialect() {
1.107 - return dialect;
1.108 - }
1.109 -
1.110 - private static void checkConnection(DataSource ds, String testSchema, String errMsg) {
1.111 - try (Connection conn = ds.getConnection()) {
1.112 - if (!conn.isValid(DB_TEST_TIMEOUT)) {
1.113 - throw new SQLException("Validation check failed.");
1.114 - }
1.115 - if (conn.isReadOnly()) {
1.116 - throw new SQLException("Connection is read-only and thus unusable.");
1.117 - }
1.118 - if (!conn.getSchema().equals(testSchema)) {
1.119 - throw new SQLException(String.format("Connection is not configured to use the schema %s.", testSchema));
1.120 - }
1.121 - DatabaseMetaData metaData = conn.getMetaData();
1.122 - LOG.info("Connections as {} to {}/{} ready to go.", metaData.getUserName(), metaData.getURL(), conn.getSchema());
1.123 - } catch (SQLException ex) {
1.124 - LOG.error(errMsg, ex);
1.125 - }
1.126 - }
1.127 -
1.128 - private static Optional<DataSource> retrieveDataSource(Context ctx) {
1.129 - DataSource ret = null;
1.130 - try {
1.131 - ret = (DataSource)ctx.lookup(DS_JNDI_NAME);
1.132 - LOG.info("Data source retrieved.");
1.133 - } catch (NamingException ex) {
1.134 - LOG.error("Data source {} not available.", DS_JNDI_NAME);
1.135 - LOG.error("Reason for the missing data source: ", ex);
1.136 - }
1.137 - return Optional.ofNullable(ret);
1.138 - }
1.139 -
1.140 - @Override
1.141 - public void contextInitialized(ServletContextEvent sce) {
1.142 - sc = sce.getServletContext();
1.143 -
1.144 - dataSource = null;
1.145 -
1.146 - final String contextName = Optional
1.147 - .ofNullable(sc.getInitParameter(Constants.CTX_ATTR_JNDI_CONTEXT))
1.148 - .orElse("java:comp/env");
1.149 - final String dbSchema = Optional
1.150 - .ofNullable(sc.getInitParameter(Constants.CTX_ATTR_DB_SCHEMA))
1.151 - .orElse(DB_DEFAULT_SCHEMA);
1.152 - final String dbDialect = sc.getInitParameter(Constants.CTX_ATTR_DB_DIALECT);
1.153 - if (dbDialect != null) {
1.154 - try {
1.155 - dialect = Dialect.valueOf(dbDialect);
1.156 - } catch (IllegalArgumentException ex) {
1.157 - LOG.error("Unknown or unsupported database dialect {}. Defaulting to {}.", dbDialect, dialect);
1.158 - }
1.159 - }
1.160 -
1.161 - try {
1.162 - LOG.debug("Trying to access JNDI context {}...", contextName);
1.163 - Context initialCtx = new InitialContext();
1.164 - Context ctx = (Context) initialCtx.lookup(contextName);
1.165 -
1.166 - dataSource = retrieveDataSource(ctx);
1.167 -
1.168 - dataSource.ifPresent((ds) -> checkConnection(ds, dbSchema, "Checking database connection failed"));
1.169 - } catch (NamingException | ClassCastException ex) {
1.170 - LOG.error("Cannot access JNDI resources.", ex);
1.171 - }
1.172 -
1.173 - sc.setAttribute(SC_ATTR_NAME, this);
1.174 - LOG.info("Database facade injected into ServletContext.");
1.175 - }
1.176 -
1.177 - @Override
1.178 - public void contextDestroyed(ServletContextEvent sce) {
1.179 - dataSource = null;
1.180 - }
1.181 -}
