Initial Commit

1 files changed, 66 insertions, 0 deletions

diff --git a/subsonic-main/src/main/java/net/sourceforge/subsonic/dao/schema/Schema.java b/subsonic-main/src/main/java/net/sourceforge/subsonic/dao/schema/Schema.java
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@@ -0,0 +1,66 @@
+/*
+ This file is part of Subsonic.
+
+ Subsonic is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ Subsonic is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Subsonic.  If not, see <http://www.gnu.org/licenses/>.
+
+ Copyright 2009 (C) Sindre Mehus
+ */
+package net.sourceforge.subsonic.dao.schema;
+
+import org.springframework.jdbc.core.*;
+
+/**
+ * Used for creating and evolving the database schema.
+ *
+ * @author Sindre Mehus
+ */
+public abstract class Schema {
+
+    /**
+     * Executes this schema.
+     * @param template The JDBC template to use.
+     */
+    public abstract void execute(JdbcTemplate template);
+
+    /**
+     * Returns whether the given table exists.
+     * @param template The JDBC template to use.
+     * @param table The table in question.
+     * @return Whether the table exists.
+     */
+    protected boolean tableExists(JdbcTemplate template, String table) {
+        try {
+            template.execute("select 1 from " + table);
+        } catch (Exception x) {
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Returns whether the given column in the given table exists.
+     * @param template The JDBC template to use.
+     * @param column The column in question.
+     * @param table The table in question.
+     * @return Whether the column exists.
+     */
+    protected boolean columnExists(JdbcTemplate template, String column, String table) {
+        try {
+            template.execute("select " + column + " from " + table + " where 1 = 0");
+        } catch (Exception x) {
+            return false;
+        }
+        return true;
+    }
+}