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comparison artifact-database/src/main/java/de/intevation/artifactdatabase/SQL.java @ 87:0f48188a6e02

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Added some javadoc to the artifactdatabase module. Not done yet. artifacts/trunk@839 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Sascha L. Teichmann <sascha.teichmann@intevation.de>
date Fri, 26 Mar 2010 11:40:28 +0000
parents 8447467cef86
children e27cf9c84eb8
comparison
equal deleted inserted replaced
86:b2e0cb83631c 87:0f48188a6e02
6 import java.io.InputStream; 6 import java.io.InputStream;
7 7
8 import org.apache.log4j.Logger; 8 import org.apache.log4j.Logger;
9 9
10 /** 10 /**
11 * Singleton to provide SQL statement strings as key/value pairs.
12 * This mechanism is used to encapsulate database specific SQL
13 * dialects.
14 *
11 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a> 15 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
12 */ 16 */
13 public final class SQL 17 public final class SQL
14 { 18 {
15 private static Logger logger = Logger.getLogger(SQL.class); 19 private static Logger logger = Logger.getLogger(SQL.class);
17 private SQL() { 21 private SQL() {
18 } 22 }
19 23
20 private static Properties statements; 24 private static Properties statements;
21 25
26 /**
27 * Returns key/value pairs of SQL statements for the used database
28 * backend.
29 * The concrete set of SQL statements is determined by the
30 * used JDBC database driver which is configured in conf.xml.
31 * The class name of the driver is transformed by replacing
32 * all '.' with '_' and lower case the resulting string.
33 * The transformed string is used to load a properties file
34 * in '/sql/' which should contain the statements.
35 * Example:<br>
36 * <code>org.postgresql.Driver</code> results in loading of
37 * <code>/sql/org-postgresql-driver.properties</code>.
38 * @return The key/value pairs of SQL statements.
39 */
22 public static final synchronized Properties getStatements() { 40 public static final synchronized Properties getStatements() {
23 if (statements == null) { 41 if (statements == null) {
24 statements = loadStatements(); 42 statements = loadStatements();
25 } 43 }
26 return statements; 44 return statements;
59 } 77 }
60 78
61 return properties; 79 return properties;
62 } 80 }
63 81
82 /**
83 * Returns a particular SQL statement for a given key.
84 * @param key The key of the statement.
85 * @return The corresponing SQL statement or null if none
86 * is found.
87 */
64 public static final String get(String key) { 88 public static final String get(String key) {
65 return getStatements().getProperty(key); 89 return getStatements().getProperty(key);
66 } 90 }
67 } 91 }
68 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: 92 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
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