Java Class Dependency Analyzer

Introduction

This is a set of command-line utilities that scan class files and selected support files in local Maven projects and generates reports about the dependencies between files. The purpose is to facilitate reorganizing code by moving it between Maven modules.

Installation

Right now, all operations are done via local Maven commands:

1. Download the [source code] (https://github.com/shawnsmith/dependency-analyzer) locally

    $ git clone git://github.com/shawnsmith/dependency-analyzer.git
   

2. Build the source and run the tests:

    $ mvn verify
   

Commands

ShowMoveCandidates

Generates a "moves file" containing list of classes that may be moved from one Maven to another without breaking any other Maven modules. Generally, you will need to go though the output file and trim it down to the subset of classes you actually want to move.

Usage:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoveCandidates
  -Dexec.args="<options>"

Options:

• -root <directory> - directory containing all source files and compiled classes, including Maven pom.xml files.
• -src <maven-module-descriptor> - the source Maven module.
• -dest <maven-module-descriptor> - the destination Maven module.
• -moves <file-name - the name of the output file to write the move candidates to, instead of the default stdout.
• -refs <file-name> - an optional file in the "moves file" format that lists Maven modules and classes that must be visible to those modules. This file can be used to add class dependencies that aren't discovered by the regular class scanner because of unsupported file formats, etc.
• -group <maven-groupId> - default Maven group ID, used when parsing or displaying Maven module descriptors.
• -package <java-package-prefix> - Java classes outside this package are ignored.

Example:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoves
  -Dexec.args="-root /home/scott/source -group com.example -package com.example -src product-api -dest product-app"

ShowMoveErrors

Show a classes that likely won't compile or will have class dependency errors once a set of proposed moves take place. The proposed moves are described in a "moves file" (see below).

Usage:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoveErrors
  -Dexec.args="<options>"

Options:

• -root <directory> - directory containing all source files and compiled classes, including Maven pom.xml files.
• -moves <file-name - the name of a "move files" that list classes to move and their final destination.
• -refs <file-name> - an optional file in the "moves file" format that lists Maven modules and classes that must be visible to those modules. This file can be used to add class dependencies that aren't discovered by the regular class scanner because of unsupported file formats, etc.
• -group <maven-groupId> - default Maven group ID, used when parsing or displaying Maven module descriptors.
• -package <java-package-prefix> - Java classes outside this package are ignored.

Example:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoveErrors
  -Dexec.args="-root /home/scott/source -group com.example -package com.example -moves /home/scott/moves.txt"

ShowMoves

Reads a set of moves in a "moves file" and displays them back in one of two formats: (1) as a de-dup'ed, sorted "moves files" or (2) as a shell script of "svn mkdir" and "svn mv" commands.

Usage:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoves
  -Dexec.args="<options>"

Options:

• -root <directory> - directory containing all source files and compiled classes, including Maven pom.xml files.
• -moves <file-name - the name of a "move files" that list classes to move and their final destination.
• -group <maven-groupId> - default Maven group ID, used when parsing or displaying Maven module descriptors.
• -package <java-package-prefix> - Java classes outside this package are ignored.
• -svn - Display output as a set of Subversion mkdir and move commands instead of in the default "moves file" format.

Example:

mvn -q exec:java
  -Dexec.mainClass=com.bazaarvoice.scratch.dependencies.ShowMoves
  -Dexec.args="-root /home/scott/source -group com.example -package com.example -moves /home/scott/moves.txt"

Moves Files

A number of the tools accept or produce a "moves file", a file listing a set of class names or file names grouped by Maven module. The file format is simple:

• Lines containing only whitespace are ignored, as are lines where the first non-whitespace character is a # (ie. comment lines)
• Otherwise, lines where the first character is not whitespace must be a Maven module descriptor of the form <groupId>:<artifactId>, where if the <groupId>: prefix is missing the default group specified on the command-line is assumed. For example: com.example:product-dao product-app
• Otherwise, lines are assumed to contain a classname or a filename, relative to the classpath root. These identify a file or class that belongs to the preceeding Maven module descriptor.

For example:

product-dao
    com.example.model.MyModel
    com/example/model/MyModel.hbm.xml
    com.example.dao.MyDao
    com.example.dao.hibernate.MyDaoHibernate

product-app
    com.example.service.MyService
    com.example.service.impl.MyServiceImpl
    META-INF/spring.handlers

product-web
    WEB-INF/web.xml
    WEB-INF/applicationContext.xml
    WEB-INF/tapestry.application
    WEB-INF/MyPage.page

For simulating moves, this file lists a set of classes and files and their final location after the move has finished. Note that the source of the moves are not specified--they are discovered by scanning the files on disk.

Class Scanner

The dependency analyzer scans class files and selected support files to detect dependencies between files. Usually these dependencies are of the form "classA depends on classB".

Java class files

Scans the following for references to other Java classes:

• target/classes/**/*.class

This finds most runtime dependencies between classes. Dependencies that are missed include the following:

• Dynamic class loading-related dependencies, eg. Class.forName()
• Unused imports
• References to static final primitive and String values.
• Local variable types unless the .class files are compiled with debug information
• Annotations on local variables (these are rare)
• Some generic type parameters in expressions.

Spring XML files

Scans the following for references to Java classes and other Spring XML files:

• target/classes/**/applicationContext*.xml, *-servlet*.xml, spring.handlers
• src/main/resources/**/applicationContext*.xml, *-servlet*.xml, spring.handlers
• src/main/webapp/WEB-INF/**/applicationContext*.xml, *-servlet*.xml, spring.handlers

For the most part, Java class references are identified by looking at the class attribute on all XML elements.

The "spring.handlers" file is assumed to be a properties files where all key=value pairs have Java class name values.

Spring annotations in the Java source files are ignored.

Servlet web.xml files

Scans the following for references to Java classes and other Spring XML files:

• target/classes/**/web.xml
• src/main/resources/**/web.xml
• src/main/webapp/WEB-INF/**/web.xml

Java class references are identified by looking at the text values of *-class XML elements.

Hibernate XML files

Scans the following for references to Java classes:

• target/classes/**/*.hbm.xml
• src/main/resources/**/*.hbm.xml
• src/main/webapp/WEB-INF/**/*.hbm.xml

Java class references are identified by looking at the class and type attributes on all XML elements and by the name attribute on class elements.

IBatis XML files

Scans the following for references to Java classes:

• target/classes/**/*.ibatis.xml, sqlmap-config*.xml
• src/main/resources/**/*.ibatis.xml, sqlmap-config*.xml
• src/main/webapp/WEB-INF/**/*.ibatis.xml, sqlmap-config*.xml

Java class references are identified by looking at the parameterClass and resultClass attributes on all XML elements.

Tapestry page and component files

Scans the following for references to Java classes:

• target/classes/**/*.page, *.jwc*, *.script
• src/main/resources/**/*.page, *.jwc*, *.script
• src/main/webapp/WEB-INF/**/*.page, *.jwc*, *.script

For the most part, Java class references are identified by looking at the class and type attributes on all XML elements.

Currently supports only Tapestry 3.x DTDs.