This short document is provided to help programmers through the internals of
the PostgreSQL JDBC driver.

Last update: January 17 2001 peter@retep.org.uk

build.xml
---------

As of 7.1, we now use the ANT build tool to build the driver. ANT is part of
the Apache/Jakarta project, and provides far superior build capabilities. You
can find ANT from http://jakarta.apache.org/ant/index.html and being pure java
it will run on any java platform.

So far I've tested it under JDK1.2.x & JDK1.3 (both Linux & NT) but not yet with
JDK1.1.8. Because of the latter the Makefile still works for now, but should be
gone for 7.2.

Anyhow, to build, simply type ant and the .jar file will be created and put into
the jars directory.

Tip: If you run ant from the sources root directory (ie: where the configure
script is located) you will find another build.xml file. It is advised to run
ant from that directory as it will then compile some auxilary Java/JDBC
utilities that are located under the /contrib/retep directory.

Makefile
--------

Prior to 7.1, all compilation must be done by using Make. This is because there
are three versions of the driver, one for JDBC1 (for JDK 1.1.x) and the others
for JDBC2 (for JDK 1.2 or later, one standard and one enterprise).

As of 7.1, ANT is the build tool of choice. Just compare Makefile and build.xml
to see why! Make just isn't suited to Java.

Building with just the JDK
--------------------------

This is not advised, simply because you have to make sure you include the
correct classes, and the fact that org.postgresql.Driver is built on the fly.
Also, javac won't pick up all the classes because some (org.postgresql.geometric
for example) are loaded dynamically.

org/postgresql/Driver.java.in
-----------------------------

Because there are three versions of the driver, the org.postgresql.Driver class
is built dynamically. To build correctly ANT copies the Driver.java.in file to
Driver.java replacing certain values according to the required driver.

The replaced values are of the format %VALUE%, ie: %MAJORVERSION% is replaced
with 7 in the 7.1 version of the driver.

postgresql.jar
--------------

This jar file is produced by ANT, and contains the driver for your JDK platform.

If you downloaded a precompiled binary from the web, you may find that the
jar file will be named differently. These are identical to this file but are
named according to the backend and jdk versions.

The naming convention is of the form: jdbc-#.#-#.##.jar

ie: for 7.1
  jdbc-7.1-1.1.jar    JDBC Driver for JDK1.1.8
  jdbc-7.1-1.2.jar    JDBC Driver for JDK1.2 & JDK1.3
  jdbc-7.1-1.2ent.jar JDBC Driver for JDK1.2 & JDK1.3 Enterprise Editions

If in the future there are any 1.3 specific classes then there will be two new
jar files.

Note: All the precompiled binaries are built under Linux.

jdbc.jpx
--------

This is a JBuilder4 project file. It's here to allow JBuilder to be used to
develop the driver. Mainly for it's Editor's features like syntax checking and
auto-completion etc.

IMPORTANT: You CAN NOT build the driver from within JBuilder. You must use ANT.
           This is because of the three versions of the JDK. If you try to use
           JBuilder, it will try to build everything, and it will just not work.

Importing packages
------------------

In user code, you may have to import one or more packages, if and only if you
are using the non jdbc extensions (like FastPath, or LargeObject).

DO NOT import the postgresql, postgresql.jdbc1 or postgresql.jdbc2 packages!

Internally, some classes will import the packages when there is a link between
them and the other packages. However, the above rule still applies. It's there
because Javac becomes confused between the different places that similar class
names are present.

However, there are places where they need to refer to classes in the postgresql
package. In this case, import the individual classes, and not the entire
package.

ie:	import postgresql.Field

    NOT	import postgresql.*

Package Layout
--------------

The driver is split into several packages:

org.postgresql			core classes that can be accessed by user code
org.postgresql.core             core classes not normally used externally
org.postgresql.jdbc1		classes used only in implementing JDBC 1
org.postgresql.jdbc2		classes used only in implementing JDBC 2
org.postgresql.fastpath		FastPath to backend functions
org.postgresql.geometric		2D Geometric types mapped to Java Objects
org.postgresql.largeobject		Low level Large Object access
org.postgresql.util			Utility classes


Package org.postgresql
------------------

This package holds the core classes.

Driver		registers the driver when it's loaded, and determines which
		Connection class (in jdbc1 or jdbc2 packages) to use when
		connecting to a database.

Field		Used internally to represent a Field
PG_Stream	Used internally to manage the network stream.
PostgresqlDataSource
                Exists in the Java2 Enterprise edition driver only and is the
                enterprise equivalent to Driver

	These classes contains common code that is not dependent to the
	two JDBC specifications.

Connection	Common code used in Connections, mainly Network Protocol stuff.
ResultSet	Common code used in ResultSet's

Package org.postgresql.core
-----------------------

New in 7.1, this is where core classes (common to all versions) will exist. Any
new class that would have gone into org.postgresql must go in here instead.

BytePoolDim1    Handles a pool of byte[] arrays.
BytePoolDim2    Handles a pool of byte[][] arrays
MemoryPool      Interface for managing MemoryPools. Not used (yet).
ObjectPool      Interface for an Object Pool
SimpleObjectPool Class that implements ObjectPool and used by BytePoolDim#
Encoding        Character encoding logic, mainly for Connection and PG_Stream.

Package org.postgresql.fastpath
---------------------------

Fastpath	Handles executing a function on the PostgreSQL Backend
FastpathArg	Defines an argument for a function call

Package org.postgresql.geometric
----------------------------

PGbox		Maps to postgresql type box
PGcircle	Maps to postgresql type circle
PGline		Maps to postgresql type line
PGlseg		Maps to postgresql type lseg
PGpath		Maps to postgresql type path
PGpoint		Maps to postgresql type point
PGpolygon	Maps to postgresql type polygon

Package org.postgresql.jdbc1
------------------------

The classes in this package handle the JDBC 1 Specification, for JDK 1.1.x
All interfaces in the java.sql package are present here.

Package org.postgresql.jdbc2
------------------------

The classes in this package handle the JDBC 2 Specification, for JDK 1.2
All interfaces in the java.sql, and javax.sql packages are present here.

Package org.postgresql.largeobject
------------------------------

LargeObject		Represents an open LargeObject
LargeObjectManager	Handles the opening and deleting of LargeObjects

Package org.postgresql.util
-----------------------

PGmoney		Maps to postgresql type money
PGobject	Used to represent postgresql types that have no Java equivalent
PGtokenizer	Helper class for the geometric types
Serialize	Used to serialise Java objects into tabes, rather than Blobs
UnixCrypt	Used to handle crypt authentication

