[FIXED] Using Search Engine to implement call hierarchy (getting all the methods that invoke a certain method) in Java/eclipse

Issue

I have a Java Project named "javaProject" which has two classes Hello and ReferenceHello.

Hello.java

package com.prosseek.test;

public class Hello {
    public void world()
    {
        System.out.println("Hello world");
    }
    
    public void referWorld()
    {
        world();
    }
}

ReferenceHello.java

package com.prosseek.test;

public class ReferenceHello {
    public void referWorld()
    {
        Hello h = new Hello();
        h.world();
    }
}

I can find all the methods that references (or invokes) Hello.world() using Search/Java dialog box.

I'd like to get the same result programmatically using Search Engine. This is the code that I came up with, however it returns nothing.

public void testIt() throws CoreException {
    String projectName = "javaProject";
    IJavaProject javaProject = JavaProjectHelper.createJavaProject(projectName);
    
    String targetMethodName = "world";
    SearchPattern pattern = SearchPattern.createPattern(
            targetMethodName, 
            IJavaSearchConstants.METHOD, 
            IJavaSearchConstants.REFERENCES,
            SearchPattern.R_CASE_SENSITIVE // <--- ????
            );
    
    boolean includeReferencedProjects = false;
    IJavaElement[] javaProjects = new IJavaElement[] {javaProject};
    IJavaSearchScope scope = SearchEngine.createJavaSearchScope(javaProjects, includeReferencedProjects); // <--- ????

    SearchRequestor requestor = new SearchRequestor() {
        @Override
        public void acceptSearchMatch(SearchMatch match)
                throws CoreException {
            System.out.println(match.getElement());
        }
    };
    SearchEngine searchEngine = new SearchEngine();
    searchEngine.search(
            pattern, 
            new SearchParticipant[] { SearchEngine.getDefaultSearchParticipant()}, 
            scope, 
            requestor, 
            null);      
}

• What might be wrong in my search code?
• Is there other way to get the call hierarchy in a eclipse plugin programmatically?

ADDED

The search code works fine, the issue was with my wrong use of JavaProjectHelper.createJavaProject. I should have opened the existing java project, not creating one with the same name. As a result, .metadata was broken and nothing was searched.

With my new getJavaProject method, everything works fine now.

private IJavaProject getJavaProject(String projectName) throws CoreException
{
    IWorkspaceRoot root= ResourcesPlugin.getWorkspace().getRoot();
    IProject project= root.getProject(projectName);
    if (!project.exists()) {
        project.create(null);
    } else {
        project.refreshLocal(IResource.DEPTH_INFINITE, null);
    }
    
    if (!project.isOpen()) {
        project.open(null);
    }
    
    IJavaProject jproject= JavaCore.create(project);
    
    return jproject;    
}

Solution

From the hint of this site. I could use the CallHierarchy API.

getCallersOf() method

package com.prosseek.asttest;

// http://www.programcreek.com/2011/07/find-all-callers-of-a-method/
import java.util.HashSet;

import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.IMember;
import org.eclipse.jdt.core.IMethod; 
import org.eclipse.jdt.internal.corext.callhierarchy.CallHierarchy;
import org.eclipse.jdt.internal.corext.callhierarchy.MethodWrapper;

public class CallHierarchyGenerator {
public HashSet<IMethod> getCallersOf(IMethod m) {

    CallHierarchy callHierarchy = CallHierarchy.getDefault();

    IMember[] members = { m };

    MethodWrapper[] methodWrappers = callHierarchy.getCallerRoots(members);
    HashSet<IMethod> callers = new HashSet<IMethod>();
    for (MethodWrapper mw : methodWrappers) {
        MethodWrapper[] mw2 = mw.getCalls(new NullProgressMonitor());
        HashSet<IMethod> temp = getIMethods(mw2);
        callers.addAll(temp);
    }

    return callers;
}

HashSet<IMethod> getIMethods(MethodWrapper[] methodWrappers) {
    HashSet<IMethod> c = new HashSet<IMethod>();
    for (MethodWrapper m : methodWrappers) {
        IMethod im = getIMethodFromMethodWrapper(m);
        if (im != null) {
            c.add(im);
        }
    }
    return c;
}

IMethod getIMethodFromMethodWrapper(MethodWrapper m) {
    try {
        IMember im = m.getMember();
        if (im.getElementType() == IJavaElement.METHOD) {
            return (IMethod) m.getMember();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}
}

findMethod utility

IMethod findMethod(IType type, String methodName) throws JavaModelException
{
    //IType type = project.findType(typeName);

    IMethod[] methods = type.getMethods();
    IMethod theMethod = null;

    for (int i = 0; i < methods.length; i++)
    {
        IMethod imethod = methods[i];
        if (imethod.getElementName().equals(methodName)) {
            theMethod = imethod;
        }
    }

    if (theMethod == null)
    {           
        System.out.println("Error, method" + methodName + " not found");
        return null;
    }

    return theMethod;
}

The usage

    CallHierarchyGenerator callGen = new CallHierarchyGenerator();

    IMethod m = findMethod(type, "world");
    Set<IMethod> methods = new HashSet<IMethod>();
    methods = callGen.getCallersOf(m);
    for (Iterator<IMethod> i = methods.iterator(); i.hasNext();)
    {
        System.out.println(i.next().toString());
    }

The result

void referWorld() {key=Lcom/prosseek/test/ReferenceHello;.referWorld()V} [in ReferenceHello [in ReferenceHello.java [in com.prosseek.test [in src [in javaTest]]]]]
void referWorld() {key=Lcom/prosseek/test/Hello;.referWorld()V} [in Hello [in Hello.java [in com.prosseek.test [in src [in javaTest]]]]]

Answered By - prosseek