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This patch merges the identical methods from the JDBC1 and JDBC2

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connection implementations (org.postgresql.jdbc[1|2].Connection) into
their superclass (org.postgresql.Connection).

It also changes the close() methods of Connection and PG_Stream, so that
PG_Stream no longer is responsible for sending the termination packet 'X'
to the backend. I figured that protocol-level stuff like that belonged in
Connection more than in PG_Stream.

Anders Bengtsson
This commit is contained in:
Bruce Momjian
2001-07-30 14:51:19 +00:00
parent 462b7d46d1
commit 509f5d241a
4 changed files with 239 additions and 476 deletions
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238
src/interfaces/jdbc/org/postgresql/Connection.java
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@ -11,7 +11,7 @@ import org.postgresql.util.*;
import org.postgresql.core.Encoding;
/**
* $Id: Connection.java,v 1.20 2001/07/21 18:56:17 momjian Exp $
* $Id: Connection.java,v 1.21 2001/07/30 14:51:19 momjian Exp $
*
* This abstract class is used by org.postgresql.Driver to open either the JDBC1 or
* JDBC2 versions of the Connection class.
@ -76,6 +76,11 @@ public abstract class Connection
// Now handle notices as warnings, so things like "show" now work
public SQLWarning firstWarning = null;
/**
* Cache of the current isolation level
*/
private int isolationLevel = java.sql.Connection.TRANSACTION_READ_COMMITTED;
// The PID an cancellation key we get from the backend process
public int pid;
public int ckey;
@ -788,7 +793,236 @@ public abstract class Connection
*/
protected abstract java.sql.ResultSet getResultSet(org.postgresql.Connection conn,java.sql.Statement stat, Field[] fields, Vector tuples, String status, int updateCount,int insertOID) throws SQLException;
public abstract void close() throws SQLException;
/**
* In some cases, it is desirable to immediately release a Connection's
* database and JDBC resources instead of waiting for them to be
* automatically released (cant think why off the top of my head)
*
* <B>Note:</B> A Connection is automatically closed when it is
* garbage collected. Certain fatal errors also result in a closed
* connection.
*
* @exception SQLException if a database access error occurs
*/
public void close() throws SQLException {
if (pg_stream != null) {
try {
pg_stream.SendChar('X');
pg_stream.flush();
pg_stream.close();
} catch (IOException e) {}
pg_stream = null;
}
}
/**
* A driver may convert the JDBC sql grammar into its system's
* native SQL grammar prior to sending it; nativeSQL returns the
* native form of the statement that the driver would have sent.
*
* @param sql a SQL statement that may contain one or more '?'
* parameter placeholders
* @return the native form of this statement
* @exception SQLException if a database access error occurs
*/
public String nativeSQL(String sql) throws SQLException {
return sql;
}
/**
* The first warning reported by calls on this Connection is
* returned.
*
* <B>Note:</B> Sebsequent warnings will be changed to this
* SQLWarning
*
* @return the first SQLWarning or null
* @exception SQLException if a database access error occurs
*/
public SQLWarning getWarnings() throws SQLException {
return firstWarning;
}
/**
* After this call, getWarnings returns null until a new warning
* is reported for this connection.
*
* @exception SQLException if a database access error occurs
*/
public void clearWarnings() throws SQLException {
firstWarning = null;
}
/**
* You can put a connection in read-only mode as a hunt to enable
* database optimizations
*
* <B>Note:</B> setReadOnly cannot be called while in the middle
* of a transaction
*
* @param readOnly - true enables read-only mode; false disables it
* @exception SQLException if a database access error occurs
*/
public void setReadOnly(boolean readOnly) throws SQLException {
this.readOnly = readOnly;
}
/**
* Tests to see if the connection is in Read Only Mode. Note that
* we cannot really put the database in read only mode, but we pretend
* we can by returning the value of the readOnly flag
*
* @return true if the connection is read only
* @exception SQLException if a database access error occurs
*/
public boolean isReadOnly() throws SQLException {
return readOnly;
}
/**
* If a connection is in auto-commit mode, than all its SQL
* statements will be executed and committed as individual
* transactions. Otherwise, its SQL statements are grouped
* into transactions that are terminated by either commit()
* or rollback(). By default, new connections are in auto-
* commit mode. The commit occurs when the statement completes
* or the next execute occurs, whichever comes first. In the
* case of statements returning a ResultSet, the statement
* completes when the last row of the ResultSet has been retrieved
* or the ResultSet has been closed. In advanced cases, a single
* statement may return multiple results as well as output parameter
* values. Here the commit occurs when all results and output param
* values have been retrieved.
*
* @param autoCommit - true enables auto-commit; false disables it
* @exception SQLException if a database access error occurs
*/
public void setAutoCommit(boolean autoCommit) throws SQLException {
if (this.autoCommit == autoCommit)
return;
if (autoCommit)
ExecSQL("end");
else {
ExecSQL("begin");
doIsolationLevel();
}
this.autoCommit = autoCommit;
}
/**
* gets the current auto-commit state
*
* @return Current state of the auto-commit mode
* @exception SQLException (why?)
* @see setAutoCommit
*/
public boolean getAutoCommit() throws SQLException {
return this.autoCommit;
}
/**
* The method commit() makes all changes made since the previous
* commit/rollback permanent and releases any database locks currently
* held by the Connection. This method should only be used when
* auto-commit has been disabled. (If autoCommit == true, then we
* just return anyhow)
*
* @exception SQLException if a database access error occurs
* @see setAutoCommit
*/
public void commit() throws SQLException {
if (autoCommit)
return;
ExecSQL("commit");
autoCommit = true;
ExecSQL("begin");
doIsolationLevel();
autoCommit = false;
}
/**
* The method rollback() drops all changes made since the previous
* commit/rollback and releases any database locks currently held by
* the Connection.
*
* @exception SQLException if a database access error occurs
* @see commit
*/
public void rollback() throws SQLException {
if (autoCommit)
return;
ExecSQL("rollback");
autoCommit = true;
ExecSQL("begin");
doIsolationLevel();
autoCommit = false;
}
/**
* Get this Connection's current transaction isolation mode.
*
* @return the current TRANSACTION_* mode value
* @exception SQLException if a database access error occurs
*/
public int getTransactionIsolation() throws SQLException {
clearWarnings();
ExecSQL("show xactisolevel");
SQLWarning warning = getWarnings();
if (warning != null) {
String message = warning.getMessage();
clearWarnings();
if (message.indexOf("READ COMMITTED") != -1)
return java.sql.Connection.TRANSACTION_READ_COMMITTED;
else if (message.indexOf("READ UNCOMMITTED") != -1)
return java.sql.Connection.TRANSACTION_READ_UNCOMMITTED;
else if (message.indexOf("REPEATABLE READ") != -1)
return java.sql.Connection.TRANSACTION_REPEATABLE_READ;
else if (message.indexOf("SERIALIZABLE") != -1)
return java.sql.Connection.TRANSACTION_SERIALIZABLE;
}
return java.sql.Connection.TRANSACTION_READ_COMMITTED;
}
/**
* You can call this method to try to change the transaction
* isolation level using one of the TRANSACTION_* values.
*
* <B>Note:</B> setTransactionIsolation cannot be called while
* in the middle of a transaction
*
* @param level one of the TRANSACTION_* isolation values with
* the exception of TRANSACTION_NONE; some databases may
* not support other values
* @exception SQLException if a database access error occurs
* @see java.sql.DatabaseMetaData#supportsTransactionIsolationLevel
*/
public void setTransactionIsolation(int level) throws SQLException {
isolationLevel = level;
doIsolationLevel();
}
/**
* Helper method used by setTransactionIsolation(), commit(), rollback()
* and setAutoCommit(). This sets the current isolation level.
*/
protected void doIsolationLevel() throws SQLException {
String q = "SET TRANSACTION ISOLATION LEVEL";
switch(isolationLevel) {
case java.sql.Connection.TRANSACTION_READ_COMMITTED:
ExecSQL(q + " READ COMMITTED");
return;
case java.sql.Connection.TRANSACTION_SERIALIZABLE:
ExecSQL(q + " SERIALIZABLE");
return;
default:
throw new PSQLException("postgresql.con.isolevel",new Integer(isolationLevel));
}
}
/**
* A sub-space of this Connection's database may be selected by