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Attached is my attempt to clean up the horrors of the ExecSQL() method in

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the JDBC driver.

I've done this by extracting it into a new method object called
QueryExecutor (should go into org/postgresql/core/) and then taking it
apart into different methods in that class.

A short summary:

* Extracted ExecSQL() from Connection into a method object called
  QueryExecutor.

* Moved ReceiveFields() from Connection to QueryExecutor.

* Extracted parts of the original ExecSQL() method body into smaller
  methods on QueryExecutor.

* Bug fix: The instance variable "pid" in Connection was used in two
  places with different meaning. Both were probably in dead code, but it's
  fixed anyway.

Anders Bengtsson
REL7_2_STABLE
Bruce Momjian 25 years ago
parent d99794e613
commit e30b283f30
3 changed files with 9 additions and 166 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 167
      src/interfaces/jdbc/org/postgresql/Connection.java
  2. 4
      src/interfaces/jdbc/org/postgresql/jdbc1/Connection.java
  3. 4
      src/interfaces/jdbc/org/postgresql/jdbc2/Connection.java

167
src/interfaces/jdbc/org/postgresql/Connection.java
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@ -8,10 +8,10 @@ import org.postgresql.Field;
import org.postgresql.fastpath.*;
import org.postgresql.largeobject.*;
import org.postgresql.util.*;
import org.postgresql.core.Encoding;
import org.postgresql.core.*;
/**
* $Id: Connection.java,v 1.26 2001/08/24 16:50:12 momjian Exp $
* $Id: Connection.java,v 1.27 2001/09/06 03:13:34 momjian Exp $
*
* This abstract class is used by org.postgresql.Driver to open either the JDBC1 or
* JDBC2 versions of the Connection class.
@ -348,166 +348,9 @@ public abstract class Connection
* @return a ResultSet holding the results
* @exception SQLException if a database error occurs
*/
public java.sql.ResultSet ExecSQL(String sql,java.sql.Statement stat) throws SQLException
public java.sql.ResultSet ExecSQL(String sql, java.sql.Statement stat) throws SQLException
{
// added Jan 30 2001 to correct maxrows per statement
int maxrows=0;
if(stat!=null)
maxrows=stat.getMaxRows();
// added Oct 7 1998 to give us thread safety.
synchronized(pg_stream) {
// Deallocate all resources in the stream associated
// with a previous request.
// This will let the driver reuse byte arrays that has already
// been allocated instead of allocating new ones in order
// to gain performance improvements.
// PM 17/01/01: Commented out due to race bug. See comments in
// PG_Stream
//pg_stream.deallocate();
Field[] fields = null;
Vector tuples = new Vector();
byte[] buf = null;
int fqp = 0;
boolean hfr = false;
String recv_status = null, msg;
int update_count = 1;
int insert_oid = 0;
SQLException final_error = null;
buf = encoding.encode(sql);
try
{
pg_stream.SendChar('Q');
pg_stream.Send(buf);
pg_stream.SendChar(0);
pg_stream.flush();
} catch (IOException e) {
throw new PSQLException("postgresql.con.ioerror",e);
}
while (!hfr || fqp > 0)
{
Object tup=null; // holds rows as they are recieved
int c = pg_stream.ReceiveChar();
switch (c)
{
case 'A': // Asynchronous Notify
pid = pg_stream.ReceiveInteger(4);
msg = pg_stream.ReceiveString(encoding);
break;
case 'B': // Binary Data Transfer
if (fields == null)
throw new PSQLException("postgresql.con.tuple");
tup = pg_stream.ReceiveTuple(fields.length, true);
// This implements Statement.setMaxRows()
if(maxrows==0 || tuples.size()<maxrows)
tuples.addElement(tup);
break;
case 'C': // Command Status
recv_status = pg_stream.ReceiveString(encoding);
// Now handle the update count correctly.
if(recv_status.startsWith("INSERT") || recv_status.startsWith("UPDATE") || recv_status.startsWith("DELETE") || recv_status.startsWith("MOVE")) {
try {
update_count = Integer.parseInt(recv_status.substring(1+recv_status.lastIndexOf(' ')));
} catch(NumberFormatException nfe) {
throw new PSQLException("postgresql.con.fathom",recv_status);
}
if(recv_status.startsWith("INSERT")) {
try {
insert_oid = Integer.parseInt(recv_status.substring(1+recv_status.indexOf(' '),recv_status.lastIndexOf(' ')));
} catch(NumberFormatException nfe) {
throw new PSQLException("postgresql.con.fathom",recv_status);
}
}
}
if (fields != null)
hfr = true;
else
{
try
{
pg_stream.SendChar('Q');
pg_stream.SendChar(' ');
pg_stream.SendChar(0);
pg_stream.flush();
} catch (IOException e) {
throw new PSQLException("postgresql.con.ioerror",e);
}
fqp++;
}
break;
case 'D': // Text Data Transfer
if (fields == null)
throw new PSQLException("postgresql.con.tuple");
tup = pg_stream.ReceiveTuple(fields.length, false);
// This implements Statement.setMaxRows()
if(maxrows==0 || tuples.size()<maxrows)
tuples.addElement(tup);
break;
case 'E': // Error Message
msg = pg_stream.ReceiveString(encoding);
final_error = new SQLException(msg);
hfr = true;
break;
case 'I': // Empty Query
int t = pg_stream.ReceiveChar();
if (t != 0)
throw new PSQLException("postgresql.con.garbled");
if (fqp > 0)
fqp--;
if (fqp == 0)
hfr = true;
break;
case 'N': // Error Notification
addWarning(pg_stream.ReceiveString(encoding));
break;
case 'P': // Portal Name
String pname = pg_stream.ReceiveString(encoding);
break;
case 'T': // MetaData Field Description
if (fields != null)
throw new PSQLException("postgresql.con.multres");
fields = ReceiveFields();
break;
case 'Z': // backend ready for query, ignore for now :-)
break;
default:
throw new PSQLException("postgresql.con.type",new Character((char)c));
}
}
if (final_error != null)
throw final_error;
return getResultSet(this, stat, fields, tuples, recv_status, update_count, insert_oid);
}
}
/**
* Receive the field descriptions from the back end
*
* @return an array of the Field object describing the fields
* @exception SQLException if a database error occurs
*/
private Field[] ReceiveFields() throws SQLException
{
int nf = pg_stream.ReceiveIntegerR(2), i;
Field[] fields = new Field[nf];
for (i = 0 ; i < nf ; ++i)
{
String typname = pg_stream.ReceiveString(encoding);
int typid = pg_stream.ReceiveIntegerR(4);
int typlen = pg_stream.ReceiveIntegerR(2);
int typmod = pg_stream.ReceiveIntegerR(4);
fields[i] = new Field(this, typname, typid, typlen, typmod);
}
return fields;
return new QueryExecutor(sql, stat, pg_stream, this).execute();
}
/**
@ -793,7 +636,7 @@ public abstract class Connection
* This returns a resultset. It must be overridden, so that the correct
* version (from jdbc1 or jdbc2) are returned.
*/
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 java.sql.ResultSet getResultSet(org.postgresql.Connection conn,java.sql.Statement stat, Field[] fields, Vector tuples, String status, int updateCount,int insertOID) throws SQLException;
/**
* In some cases, it is desirable to immediately release a Connection's

4
src/interfaces/jdbc/org/postgresql/jdbc1/Connection.java
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@ -17,7 +17,7 @@ import org.postgresql.largeobject.*;
import org.postgresql.util.*;
/**
* $Id: Connection.java,v 1.8 2001/08/24 16:50:15 momjian Exp $
* $Id: Connection.java,v 1.9 2001/09/06 03:13:34 momjian Exp $
*
* A Connection represents a session with a specific database. Within the
* context of a Connection, SQL statements are executed and results are
@ -131,7 +131,7 @@ public class Connection extends org.postgresql.Connection implements java.sql.Co
* This overides the method in org.postgresql.Connection and returns a
* ResultSet.
*/
protected 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 java.sql.ResultSet getResultSet(org.postgresql.Connection conn,java.sql.Statement stat, Field[] fields, Vector tuples, String status, int updateCount,int insertOID) throws SQLException
{
// in jdbc1 stat is ignored.
return new org.postgresql.jdbc1.ResultSet((org.postgresql.jdbc1.Connection)conn,fields,tuples,status,updateCount,insertOID);

4
src/interfaces/jdbc/org/postgresql/jdbc2/Connection.java
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@ -17,7 +17,7 @@ import org.postgresql.largeobject.*;
import org.postgresql.util.*;
/**
* $Id: Connection.java,v 1.10 2001/08/24 16:50:16 momjian Exp $
* $Id: Connection.java,v 1.11 2001/09/06 03:13:34 momjian Exp $
*
* A Connection represents a session with a specific database. Within the
* context of a Connection, SQL statements are executed and results are
@ -204,7 +204,7 @@ public class Connection extends org.postgresql.Connection implements java.sql.Co
* This overides the method in org.postgresql.Connection and returns a
* ResultSet.
*/
protected 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 java.sql.ResultSet getResultSet(org.postgresql.Connection conn, java.sql.Statement stat,Field[] fields, Vector tuples, String status, int updateCount, int insertOID) throws SQLException
{
// In 7.1 we now test concurrency to see which class to return. If we are not working with a
// Statement then default to a normal ResultSet object.

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