How to generate AST from Java source-code?

Gili_14731 0
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As far as I know, the only way to parse Java source-code into an AST (Abstract Syntax Tree) is to use the Java Compiler Tree API: com.sun.source.tree

I have two questions:

  1. What JDKs support com.sun.source.tree?
  2. Is there a portable replacement that works for all JDKs?
compiler-construction parsing java
6 Answers

Regarding your second question, there are dozens of Java parsers available in addition to Sun's. Here is a small sample:

  • Eclipse's org.eclipse.jdt.core.dom package.
  • Spoon outputs a very nice annotated parse tree with type information and variable binding (and uses Eclipse's parser internally)
  • ANTLR is a parser-generator, but there are grammars for Java available
  • javaparser (which I have not used)

My best advice is to try each of them to see which works best for your needs.

Brett_Daniel_484950

You can possibly take the tools.jar and use it. javac is open source so you can just grab that code (assuming you can deal with the license). Antlr has grammars for Java as well.

TofuBeer_658680

I've used Eclipse's AST parser. I found it to be pretty good (well it was part of an Eclipse plug-in so it did make sense to use it). See Exploring Eclipse's ASTParser.

user_531830

It is not the only way.

See our Java Front End, which is a full featured Java parser built on top of the DMS Software Reengineering Toolkit. It parses Java, and builds ASTs as internal data structures.

The point of DMS is that it provides a huge variety of additional useful machinery (attribute grammars, symbol tables, flow analysis, AST manipulation including access and update, as well as source-to-source transformations) to analyze and transform that AST into results and/or modified source code. If you get "just" a Java parser (e.g., JavaCC + Java grammar) you will, IMHO, not be able to do a lot with it. DMS makes it possible to do a lot, without having to invent all that extra machinery yourself.

If you really don't want to use the extra machinery DMS provides, it will dump the tree as XML.

user_1201630
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