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jdwglib Technical Specifications

Overview

The Java DWG Library (jdwglib) is a Java libray designed for reading, handling and

writing drawing files in the Autodesk DWG format. This document is the design

specification for the classes, methods and algorithms implemented in the Java DWG

Library.

jdwglib has two different parts, first for DWG file accesing, and second for DWG file

handling. The part for accesing DWG files support the reading of DWG files and in

future versions we hope that writing of DWG files will be supported too. The part for

handling DWG files is designed for managing DWG complex objects like polylines or

blocks with the objective that the spatial position and the attributes of DWG objects

will be definitive and no one operation is required for obtaining the same results

that Autocad.

The detailed documentation of the class hierarchy and methods will be presented in the

form of JavaDoc for the source code.

Other resources

- Pythoncad DWG Library by Art Haas (www.pythoncad.org). The part of jdwglib that reads

  DWG files is a port of this library with an object oriented model added.

- The AutoCAD R13/R14/R2000 DWG File Specification by the OpenDWG Alliance. This is the

  public specification of the DWG format obtained using reverse engineering methods by

  the OpenDWG Alliance (www.opendwg.org).

Design goals

The design of jdwglib is intended to fulfil the following goals:

- jdwglib must return the definitive set of DWG objects. Geometric and

  non geometric attributes of these objects will be enough for its correct and complete

  representation.

- The jdwglib interface must be easy to use, even by someone that hasn't advanced

  CAD knowledge.

- jdwglib will be fast enough to be used in a production environment.

- The algorithms and code used in jdwglib will be clear and well-structured, to

  facilitate understanding by other developers.

Object model

The package javacad.util contains some general classes that are useful for handling

DWG objects and other objects in a GIS environment. Their use is described in the

JavaDoc documentation.

The package jdwglib contains the classes for reading and managing DWG files and its

objects. Their use is described in the JavaDoc documentation.