From: Chris Jaekl <cejaekl@yahoo.com>
Date: Fri, 11 Dec 2015 14:34:48 +0000 (+0900)
Subject: Start support for Sqlite
X-Git-Url: https://jaekl.net/gitweb/?a=commitdiff_plain;h=01f0bef1b13c6b9f5b370372d36ad4d6149ff2c3;p=cfb.git

Start support for Sqlite
---

diff --git a/prod/net/jaekl/cfb/db/driver/DbDriver.java b/prod/net/jaekl/cfb/db/driver/DbDriver.java
index bbe38f8..b8d1ee6 100644
--- a/prod/net/jaekl/cfb/db/driver/DbDriver.java
+++ b/prod/net/jaekl/cfb/db/driver/DbDriver.java
@@ -31,6 +31,8 @@ public abstract class DbDriver {
 	
 	public abstract Connection connect(String host, int port, String dbName, String user, String pass) throws SQLException;
 	
+	public abstract long nextVal(Connection con, Sequence seq) throws SQLException;
+	
 	public boolean createTable(Connection con, Table table) throws SQLException 
 	{
 		String sql = createTableSql(table);
@@ -183,22 +185,6 @@ public abstract class DbDriver {
 		return count;
 	}
 	
-	public long nextVal(Connection con, Sequence seq) throws SQLException
-	{
-		String sql = nextValSql(seq);
-		
-		try (PreparedStatement ps = con.prepareStatement(sql)) 
-		{
-			try (ResultSet rs = ps.executeQuery()) {
-				if (rs.next()) {
-					return rs.getLong(1);
-				}
-			}
-		}
-		
-		throw new SQLException("No value returned for sequence:  " + sql);
-	}
-	
 	int checkFlushBatch(PreparedStatement ps, int pendingValues, boolean forceFlush) throws SQLException
  	{
 		int count = 0;
@@ -383,8 +369,6 @@ public abstract class DbDriver {
 		return "DROP SEQUENCE " + seq.getName();
 	}
 	
-	abstract protected String nextValSql(Sequence seq);
-	
 	boolean isValidInsert(Table table, Object[][] values)
 	{
 		if (null == table) return false;
@@ -401,4 +385,15 @@ public abstract class DbDriver {
 		
 		return true;
 	}
+	
+	int executeUpdate(Connection con, String sql) throws SQLException
+	{
+		try (PreparedStatement ps = con.prepareStatement(sql))
+		{
+			return ps.executeUpdate();
+		}
+		catch (SQLException exc) {
+			throw new SQLException("Failed to executeUpdate:  " + sql, exc);
+		}
+	}
 }
diff --git a/prod/net/jaekl/cfb/db/driver/PostgresqlDriver.java b/prod/net/jaekl/cfb/db/driver/PostgresqlDriver.java
index fbb3285..a828d7f 100644
--- a/prod/net/jaekl/cfb/db/driver/PostgresqlDriver.java
+++ b/prod/net/jaekl/cfb/db/driver/PostgresqlDriver.java
@@ -4,6 +4,8 @@ package net.jaekl.cfb.db.driver;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Properties;
 
@@ -31,11 +33,23 @@ public class PostgresqlDriver extends DbDriver {
 	}
 	
 	@Override 
-	public String nextValSql(Sequence seq) 
+	public long nextVal(Connection con, Sequence seq) throws SQLException
 	{
-		return " SELECT NEXTVAL('" + seq.getName() + "') ";
+		String sql = " SELECT NEXTVAL('" + seq.getName() + "') ";
+		
+		try (PreparedStatement ps = con.prepareStatement(sql)) 
+		{
+			try (ResultSet rs = ps.executeQuery()) {
+				if (rs.next()) {
+					return rs.getLong(1);
+				}
+			}
+		}
+		
+		throw new SQLException("No value returned for sequence:  " + sql);
 	}
 	
+	
 	@Override
 	protected String typeName(Type type) {
 		// Special case:  TIMESTAMPTZ stored as INTEGER (milliseconds since the epoch)
diff --git a/prod/net/jaekl/cfb/db/driver/SqliteDriver.java b/prod/net/jaekl/cfb/db/driver/SqliteDriver.java
new file mode 100644
index 0000000..1c336f5
--- /dev/null
+++ b/prod/net/jaekl/cfb/db/driver/SqliteDriver.java
@@ -0,0 +1,80 @@
+package net.jaekl.cfb.db.driver;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import net.jaekl.cfb.db.Sequence;
+
+public class SqliteDriver extends DbDriver {
+	static final long SEQ_NO_VALUE = (-1);
+	static final long SEQ_INIT_VALUE = 0;
+
+	@Override
+	public void load() throws ClassNotFoundException {
+		Class.forName("org.sqlite.JDBC");
+	}
+
+	@Override
+	public Connection connect(String host, int port, String dbName, String user, String pass) 
+		throws SQLException 
+	{
+		String url = "jdbc:sqlite:" + dbName;
+		return DriverManager.getConnection(url);
+	}
+
+	@Override
+	public long nextVal(Connection con, Sequence seq) throws SQLException 
+	{
+		final String sqlRead = "SELECT value FROM " + seq.getName();
+		final String sqlIncr = "UPDATE " + seq.getName() + " SET value=? WHERE value=?";
+		long value = SEQ_NO_VALUE;
+		
+		boolean auto = con.getAutoCommit();
+		try (
+				PreparedStatement psRead = con.prepareStatement(sqlRead);
+				PreparedStatement psIncr = con.prepareStatement(sqlIncr);
+			) 
+		{
+			con.setAutoCommit(false);
+			
+			for (int retryCount = 10; retryCount > 0; retryCount--) {
+				try ( ResultSet rs = psRead.executeQuery() ) 
+				{
+					if (rs.next()) {
+						value = rs.getLong(1);
+					}
+				}
+				
+				if (value >= SEQ_INIT_VALUE) {
+					psIncr.setLong(1, value + 1);
+					psIncr.setLong(2, value);
+					int count = psIncr.executeUpdate();
+					if (1 == count) {
+						return (value + 1);
+					}
+				}
+			}
+		}
+		finally {
+			con.setAutoCommit(auto);
+		}
+		
+		throw new SQLException("Unable to get next value for sequence " + seq.getName() + ".  Retry count exceeded.");
+	}
+	
+	@Override
+	public boolean createSequence(Connection con, Sequence seq)
+		throws SQLException
+	{
+		String sqlCreate = "CREATE TABLE " + seq.getName() + " ( value INTEGER )";
+		String sqlInsert = "INSERT INTO " + seq.getName() + " VALUES ( 0 )";
+
+		executeUpdate(con, sqlCreate);
+		executeUpdate(con, sqlInsert);
+		
+		return true;
+	}
+}