Mercurial > hg > LightPIT / file comparison

comparison: src/main/java/de/uapcore/lightpit/DatabaseFacade.java

src/main/java/de/uapcore/lightpit/DatabaseFacade.java

changeset 151
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parent 150
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child 152
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equal deleted inserted replaced
150:822b7e3d064d 151:b3f14cd4f3ab
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2018 Mike Becker. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 */
29 package de.uapcore.lightpit;
30
31 import org.slf4j.Logger;
32 import org.slf4j.LoggerFactory;
33
34 import javax.naming.Context;
35 import javax.naming.InitialContext;
36 import javax.naming.NamingException;
37 import javax.servlet.ServletContext;
38 import javax.servlet.ServletContextEvent;
39 import javax.servlet.ServletContextListener;
40 import javax.servlet.annotation.WebListener;
41 import javax.sql.DataSource;
42 import java.sql.Connection;
43 import java.sql.DatabaseMetaData;
44 import java.sql.SQLException;
45 import java.util.Optional;
46
47 /**
48 * Provides access to different privilege layers within the database.
49 */
50 @WebListener
51 public final class DatabaseFacade implements ServletContextListener {
52
53 private static final Logger LOG = LoggerFactory.getLogger(DatabaseFacade.class);
54
55 /**
56 * Timeout in seconds for the validation test.
57 */
58 private static final int DB_TEST_TIMEOUT = 10;
59
60 /**
61 * Specifies the database dialect.
62 */
63 public enum Dialect {
64 Postgres
65 }
66
67 /**
68 * The database dialect to use.
69 * <p>
70 * May be overridden by context parameter.
71 *
72 * @see Constants#CTX_ATTR_DB_DIALECT
73 */
74 private Dialect dialect = Dialect.Postgres;
75
76 /**
77 * The default schema to test against when validating the connection.
78 * <p>
79 * May be overridden by context parameter.
80 *
81 * @see Constants#CTX_ATTR_DB_SCHEMA
82 */
83 private static final String DB_DEFAULT_SCHEMA = "lightpit";
84
85 /**
86 * The attribute name in the Servlet context under which an instance of this class can be found.
87 */
88 public static final String SC_ATTR_NAME = DatabaseFacade.class.getName();
89
90 private static final String DS_JNDI_NAME = "jdbc/lightpit/app";
91 private DataSource dataSource;
92
93 /**
94 * Returns the data source.
95 *
96 * @return a data source
97 */
98 public DataSource getDataSource() {
99 return dataSource;
100 }
101
102 public Dialect getSQLDialect() {
103 return dialect;
104 }
105
106 private static void checkConnection(DataSource ds, String testSchema) {
107 try (Connection conn = ds.getConnection()) {
108 if (!conn.isValid(DB_TEST_TIMEOUT)) {
109 throw new SQLException("Validation check failed.");
110 }
111 if (conn.isReadOnly()) {
112 throw new SQLException("Connection is read-only and thus unusable.");
113 }
114 if (!conn.getSchema().equals(testSchema)) {
115 throw new SQLException(String.format("Connection is not configured to use the schema %s.", testSchema));
116 }
117 DatabaseMetaData metaData = conn.getMetaData();
118 LOG.info("Connections as {} to {}/{} ready to go.", metaData.getUserName(), metaData.getURL(), conn.getSchema());
119 } catch (SQLException ex) {
120 LOG.error("Checking database connection failed", ex);
121 }
122 }
123
124 private static DataSource retrieveDataSource(Context ctx) {
125 DataSource ret = null;
126 try {
127 ret = (DataSource) ctx.lookup(DS_JNDI_NAME);
128 LOG.info("Data source retrieved.");
129 } catch (NamingException ex) {
130 LOG.error("Data source {} not available.", DS_JNDI_NAME);
131 LOG.error("Reason for the missing data source: ", ex);
132 }
133 return ret;
134 }
135
136 @Override
137 public void contextInitialized(ServletContextEvent sce) {
138 ServletContext sc = sce.getServletContext();
139
140 dataSource = null;
141
142 final String dbSchema = Optional
143 .ofNullable(sc.getInitParameter(Constants.CTX_ATTR_DB_SCHEMA))
144 .orElse(DB_DEFAULT_SCHEMA);
145 final String dbDialect = sc.getInitParameter(Constants.CTX_ATTR_DB_DIALECT);
146 if (dbDialect != null) {
147 try {
148 dialect = Dialect.valueOf(dbDialect);
149 } catch (IllegalArgumentException ex) {
150 LOG.error("Unknown or unsupported database dialect {}. Defaulting to {}.", dbDialect, dialect);
151 }
152 }
153
154 try {
155 LOG.debug("Trying to access JNDI context ...");
156 Context initialCtx = new InitialContext();
157 Context ctx = (Context) initialCtx.lookup("java:comp/env");
158
159 dataSource = retrieveDataSource(ctx);
160
161 if (dataSource != null) {
162 checkConnection(dataSource, dbSchema);
163 }
164 } catch (NamingException | ClassCastException ex) {
165 LOG.error("Cannot access JNDI resources.", ex);
166 }
167
168 sc.setAttribute(SC_ATTR_NAME, this);
169 LOG.info("Database facade injected into ServletContext.");
170 }
171
172 @Override
173 public void contextDestroyed(ServletContextEvent sce) {
174 dataSource = null;
175 }
176 }

Mercurial Repository: LightPIT

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