Package edu.illinois.ncsa.daffodil.japi

Provides the classes necessary to compile DFDL schemas, parse and unparse files using the compiled objects, and retrieve results and parsing diagnostics

See: Description

Class Summary

Class	Description
Compiler	Compile DFDL schemas into ProcessorFactory's or reload saved parsers into DataProcessor's.
Daffodil	API Suitable for Java programmers to use.
DataLocation	Information related to a location in data
DataProcessor	Compiled version of a DFDL Schema, used to parse data and get the DFDL infoset
Diagnostic	Class containing diagnostic information
LocationInSchemaFile	Information related to locations in DFDL schema files
ParseResult	Result of calling DataProcessor.parse(java.nio.channels.ReadableByteChannel, long), containing the resulting infoset, any diagnostic information, and the final data location
ProcessorFactory	Factory to create DataProcessor's, used for parsing data
WithDiagnostics	Abstract class that adds diagnostic information to classes that extend it.

Enum Summary

Enum	Description
ValidationMode	Validation modes for validating the resulting infoset against the DFDL schema

Exception Summary

Exception	Description
InvalidParserException	This exception will be thrown as a result of attempting to reload a saved parser that is invalid (not a parser file, corrupt, etc.) or is not in the GZIP format.
InvalidUsageException	This exception will be thrown as a result of an invalid usage of the Daffodil API

Package edu.illinois.ncsa.daffodil.japi Description

Provides the classes necessary to compile DFDL schemas, parse and unparse files using the compiled objects, and retrieve results and parsing diagnostics

Overview

The main class to use is Daffodil to create a Compiler:

 Compiler c = Daffodil.compiler();
 

This can then be used to compiled a DFDL schema, and generate a ProcessorFactory:

 ProcessorFactor pf = c.compile(files);
 

This can then be used to create a DataProcessor:

 DataProcessor dp = pf.onPath("/");
 

This can then be used to parse data, returning a ParseResult, which contains the DFDL infoset in the form of a jdom2 document:

 ParseResult pr = dp.parse(data);
 org.jdom2.Document infoset = pr.result();
 

The DataProcessor.parse(java.nio.channels.ReadableByteChannel) method may be called multiple times without the need to create another data processors. For example:

 for (File f : inputFiles) {
   ParseResult pr = dp.parse(f);
   org.jdom2.Document infoset = pr.result();
 }
 

Failures & Diagnostics

It is possible that failures could occur during the creation of the ProcessorFactory, DataProcessor, or ParseResult. However, rather than throwing an exception on error (e.g. invalid DFDL schema, parse error, etc), these classes extend WithDiagnostics, which is used to determine if an error occured, and any diagnostic information (see Diagnostic) related to the step. thus, before contining, one must check WithDiagnostics.isError(). For example:

 ProcessorFactor pf = c.compile(files);
 if (pf.isError()) {
   java.util.List<Diagnostic> diags = pf.getDiagnostics();
   foreach (Diagnostic d : diags) {
     System.out.println(d.toString());
   }
   return -1;
 }
 

Saving & Reloading Parsers

In some cases, it may be beneficial to save a parser and reload it. For example, when starting up, it may be quicker to reload an already compiled parser than to compile it from scratch. To save a DataProcessor:

 DataProcessor dp = pf.onPath("/");
 dp.save(saveFile);
 

And to restore a saved DataProcessor:

 DataProcessor dp = Daffodil.reload(saveFile);
 ParseResult pr = dp.parse(data);