vogella.de

This article assume that you are familiar with Eclipse plugin development. See Eclipse Plugin Development for an introduction. For UI related activities, e.g. creating a view extension point please see Eclipse RCP tutorial.

The following will create a command which will read the project of the workspace, get all package and Java source files for these projects and read all methods for them by using the JDT Java Model API.

Create the plugin project "de.vogella.jdt.infos". Choose the "Hello World, command" as a template.

Add the following dependencies to your plugin "org.eclipse.core.resources", "org.eclipse.jdt", org.eclipse.jdt.core", "org.eclipse.core.runtime", "org.eclipse.jdt.ui", "org.eclipse.jface.text"

Change the handler to the following.

			
package de.vogella.jdt.infos.handlers;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IMethod;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.IType;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jface.text.Document;

public class SampleHandler extends AbstractHandler {

	public Object execute(ExecutionEvent event) throws ExecutionException {
		// Get the root of the workspace
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		IWorkspaceRoot root = workspace.getRoot();
		// Get all projects in the workspace
		IProject[] projects = root.getProjects();
		// Loop over all projects
		for (IProject project : projects) {
			try {
				printProjectInfo(project);
			} catch (CoreException e) {
				e.printStackTrace();
			}
		}
		return null;
	}

	private void printProjectInfo(IProject project) throws CoreException,
			JavaModelException {
		System.out.println("Working in project " + project.getName());
		// Check if we have a Java project
		if (project.isNatureEnabled("org.eclipse.jdt.core.javanature")) {
			IJavaProject javaProject = JavaCore.create(project);
			printPackageInfos(javaProject);
		}
	}

	private void printPackageInfos(IJavaProject javaProject)
			throws JavaModelException {
		IPackageFragment[] packages = javaProject.getPackageFragments();
		for (IPackageFragment mypackage : packages) {
			// Package fragments include all packages in the
			// classpath
			// We will only look at the package from the source
			// folder
			// K_BINARY would include also included JARS, e.g.
			// rt.jar
			if (mypackage.getKind() == IPackageFragmentRoot.K_SOURCE) {
				System.out.println("Package " + mypackage.getElementName());
				printICompilationUnitInfo(mypackage);

			}

		}
	}

	private void printICompilationUnitInfo(IPackageFragment mypackage)
			throws JavaModelException {
		for (ICompilationUnit unit : mypackage.getCompilationUnits()) {
			System.out.println("Source file " + unit.getElementName());
			Document doc = new Document(unit.getSource());
			System.out
					.println("Has number of lines: " + doc.getNumberOfLines());
			printIMethods(unit);

		}
	}

	private void printIMethods(ICompilationUnit unit) throws JavaModelException {
		IType[] allTypes = unit.getAllTypes();
		for (IType type : allTypes) {
			IMethod[] methods = type.getMethods();
			for (IMethod method : methods) {

				System.out.println("Method name " + method.getElementName());
				System.out.println("Signature " + method.getSignature());
				System.out.println("Return Type " + method.getReturnType());

			}
		}
	}
}

		

Start your plugin. Create a few projects in your new workspace. Create a few packages for them and a few Java files. Press the menu entry which points to your sample command.

You should see the projects, package and source files listed in the console of the calling workbench.

The following will create a command which will create a new package to existing (and open) Java projects which have the same name as the Java project. For example if you have a project "de.vogella.test" in your workspace without any package this command will create the package "de.vogella.test" in this project.

Create a new plugin project "de.vogella.jdt.newelements".

Add a new command "de.vogella.jdt.newelements.AddPackage" and put it into the menu.

Create the following handler for this command.

			
package de.vogella.jdt.newelements.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.IHandler;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jdt.core.IJavaProject;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.JavaCore;

public class AddPackage extends AbstractHandler implements IHandler {

	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		IWorkspaceRoot root = workspace.getRoot();
		// Get all projects in the workspace
		IProject[] projects = root.getProjects();
		// Loop over all projects
		for (IProject project : projects) {
			try {
				// Only work on open projects with the Java nature
				if (project.isOpen()
						&& project
								.isNatureEnabled("org.eclipse.jdt.core.javanature")) {
					IJavaProject javaProject = JavaCore.create(project);
					IFolder folder = project.getFolder("src");
					// folder.create(true, true, null);
					IPackageFragmentRoot srcFolder = javaProject
							.getPackageFragmentRoot(folder);
					IPackageFragment fragment = srcFolder
							.createPackageFragment(project.getName(), true,
									null);
					System.out.println("Juhu");
				}
			} catch (CoreException e) {
				e.printStackTrace();
			}
		}
		return null;
	}
}

		

The following will create an AST for each source file in your workspace and print out the name and the return type of each method using the AST.

Create a new plugin project "de.vogella.jdt.astsimple" using the "Hello world" template.

Maintain the following plugin dependencies.

			
Manifest-Version: 1.0
Bundle-ManifestVersion: 2
Bundle-Name: Astsimple Plug-in
Bundle-SymbolicName: de.vogella.jdt.astsimple;singleton:=true
Bundle-Version: 1.0.0
Bundle-RequiredExecutionEnvironment: JavaSE-1.6
Require-Bundle: org.eclipse.core.runtime;bundle-version="3.4.0",
 org.eclipse.ui;bundle-version="3.4.2",
 org.eclipse.jdt.core;bundle-version="3.4.4",
 org.eclipse.core.resources;bundle-version="3.4.2",
 org.eclipse.jdt.ui;bundle-version="3.4.2"

		

To get information about the AST you can use the Visitor Pattern. This allows you to add a visitor to the AST for a specific elements. In this visitor can you capture information about the object and return it after processing the AST. Create for this the following class.

			
package de.vogella.jdt.astsimple.handler;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.jdt.core.dom.ASTVisitor;
import org.eclipse.jdt.core.dom.MethodDeclaration;

public class MethodVisitor extends ASTVisitor {
	List<MethodDeclaration> methods = new ArrayList<MethodDeclaration>();

	@Override
	public boolean visit(MethodDeclaration node) {
		methods.add(node);
		return super.visit(node);
	}

	public List<MethodDeclaration> getMethods() {
		return methods;
	}
}

		

Add a new command "de.vogella.jdt.astsimple.GetInfo" and put it into the menu.

Create the following handler for this command.

			
package de.vogella.jdt.astsimple.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.resources.IWorkspace;
import org.eclipse.core.resources.IWorkspaceRoot;
import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IPackageFragment;
import org.eclipse.jdt.core.IPackageFragmentRoot;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.dom.AST;
import org.eclipse.jdt.core.dom.ASTParser;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.MethodDeclaration;

public class GetInfo extends AbstractHandler {

	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		IWorkspace workspace = ResourcesPlugin.getWorkspace();
		IWorkspaceRoot root = workspace.getRoot();
		// Get all projects in the workspace
		IProject[] projects = root.getProjects();
		// Loop over all projects
		for (IProject project : projects) {
			try {
				if (project.isNatureEnabled("org.eclipse.jdt.core.javanature")) {

					IPackageFragment[] packages = JavaCore.create(project)
							.getPackageFragments();
					// parse(JavaCore.create(project));
					for (IPackageFragment mypackage : packages) {
						if (mypackage.getKind() == IPackageFragmentRoot.K_SOURCE) {
							for (ICompilationUnit unit : mypackage
									.getCompilationUnits()) {
								// Now create the AST for the ICompilationUnits
								CompilationUnit parse = parse(unit);
								MethodVisitor visitor = new MethodVisitor();
								parse.accept(visitor);

								for (MethodDeclaration method : visitor
										.getMethods()) {
									System.out.print("Method name: "
											+ method.getName()
											+ " Return type: "
											+ method.getReturnType2());
								}

							}
						}

					}
				}
			} catch (CoreException e) {
				e.printStackTrace();
			}
		}
		return null;
	}

	/**
	 * Reads a ICompilationUnit and creates the AST DOM for manipulating the
	 * Java source file
	 * 
	 * @param unit
	 * @return
	 */

	private static CompilationUnit parse(ICompilationUnit unit) {
		ASTParser parser = ASTParser.newParser(AST.JLS3);
		parser.setKind(ASTParser.K_COMPILATION_UNIT);
		parser.setSource(unit);
		parser.setResolveBindings(true);
		return (CompilationUnit) parser.createAST(null); // parse
	}
}

		

Add the command to your menu. Run your new plugin, create a new Java project and select the command. It should print out the information about your methods in the IDE from which you started your new plugin

Thank you for practicing with this tutorial.

For questions and discussion around this article please use the www.vogella.de Google Group. Also if you note an error in this article please post the error and if possible the correction to the Group.

I believe the following is a very good guideline for asking questions in general and also for the Google group How To Ask Questions The Smart Way.