Overview of ASN1C for Java

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The ASN1C code generation tool translates an Abstract Syntax Notation 1 (ASN.1) source file into computer language source files that allow ASN.1 data to be encoded/decoded. This release of ASN1C includes options to generate code in three different languages: C, C++, or Java. This manual discusses the Java code generation capabilities. The ASN1C C/C++ Compiler User's Manual discusses the C/C++ code generation capability.

Each ASN.1 module that is encountered in an ASN.1 source file results in the generation of a series of Java source files. A separate Java file is generated for each ASN.1 production in the source file. Additional files are generated for compiler-generated productions and to hold value specification constants.

There is also a set of classes that form the run-time component of the Java package. These classes provide the primitive component building blocks that are assembled by the compiler to encode/decode complex structures. They also provide support for the managing message buffers that hold the encoded message components.

ASN1C works with the version of ASN.1 specified in ITU-T international standards X.680 through X.683. It generates code for encoding/decoding data in accordance with the following encoding rules:

Basic Encoding Rules (BER) or Distinguished Encoding Rules (DER) as published in the ITU-T X.690 standard.

Packed Encoding Rules (PER) as published in the ITU-T X.691 standard.

XML Encoding Rules (XER) as published in the ITU-T X.693 standard.

The compiler is capable of parsing all ASN.1 syntax as defined in the standards. It is capable of parsing advanced syntax including Information Object Specifications as defined in the ITU-T X.681 standard as well as Parameterized Types as defined in ITU-T X.683.

This release of the compiler contains a special executable (asn1c90.exe) that is backward compatible with deprecated features from the older X.208 and X.209 standards. These include the ANY data type and unnamed fields in SEQUENCE, SET, and CHOICE types. This version can also parse type syntax from common macro definitions such as ROSE and SNMP.