org.eclipse.flux.jdt.services.NavigationService.java Source code

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Here is the source code for org.eclipse.flux.jdt.services.NavigationService.java

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/*******************************************************************************
 * Copyright (c) 2013, 2014 Pivotal Software, Inc. and others.
 * All rights reserved. This program and the accompanying materials are made 
 * available under the terms of the Eclipse Public License v1.0 
 * (http://www.eclipse.org/legal/epl-v10.html), and the Eclipse Distribution 
 * License v1.0 (http://www.eclipse.org/org/documents/edl-v10.html). 
 *
 * Contributors:
 *     Pivotal Software, Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.flux.jdt.services;

import org.eclipse.core.resources.IResource;
import org.eclipse.flux.client.IMessageHandler;
import org.eclipse.flux.client.MessageConnector;
import org.eclipse.flux.client.MessageHandler;
import org.eclipse.jdt.core.IClassFile;
import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.ISourceRange;
import org.eclipse.jdt.core.ISourceReference;
import org.eclipse.jdt.core.JavaModelException;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * Implements "Jump to declaration" navigation for a location in a Java file.
 * @author Martin Lippert
 */
public class NavigationService {

    private LiveEditUnits liveEditUnits;
    private MessageConnector messagingConnector;
    private IMessageHandler navigationRequestHandler;

    public NavigationService(MessageConnector messagingConnector, LiveEditUnits liveEditUnits) {
        this.messagingConnector = messagingConnector;
        this.liveEditUnits = liveEditUnits;

        this.navigationRequestHandler = new MessageHandler("navigationrequest") {
            @Override
            public void handle(String messageType, JSONObject message) {
                handleNavigationRequest(message);
            }
        };
        messagingConnector.addMessageHandler(this.navigationRequestHandler);
    }

    protected void handleNavigationRequest(JSONObject message) {
        try {
            String username = message.getString("username");
            String projectName = message.getString("project");
            String resourcePath = message.getString("resource");
            int callbackID = message.getInt("callback_id");

            String liveEditID = projectName + "/" + resourcePath;
            if (liveEditUnits.isLiveEditResource(username, liveEditID)) {

                int offset = message.getInt("offset");
                int length = message.getInt("length");
                String sender = message.getString("requestSenderID");

                JSONObject navigationResult = computeNavigation(username, liveEditID, offset, length);

                if (navigationResult != null) {
                    JSONObject responseMessage = new JSONObject();
                    responseMessage.put("username", username);
                    responseMessage.put("project", projectName);
                    responseMessage.put("resource", resourcePath);
                    responseMessage.put("callback_id", callbackID);
                    responseMessage.put("requestSenderID", sender);
                    responseMessage.put("navigation", navigationResult);

                    messagingConnector.send("navigationresponse", responseMessage);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public JSONObject computeNavigation(String username, String requestorResourcePath, int offset, int length) {
        try {
            ICompilationUnit liveEditUnit = liveEditUnits.getLiveEditUnit(username, requestorResourcePath);
            if (liveEditUnit != null) {
                IJavaElement[] elements = liveEditUnit.codeSelect(offset, length);

                if (elements != null && elements.length > 0) {
                    JSONObject result = new JSONObject();

                    IJavaElement element = elements[0];
                    IResource resource = element.getResource();

                    //if the selected element corresponds to a resource in workspace, navigate to it
                    if (resource != null && resource.getProject() != null) {
                        String projectName = resource.getProject().getName();
                        String resourcePath = resource.getProjectRelativePath().toString();

                        result.put("project", projectName);
                        result.put("resource", resourcePath);

                        if (element instanceof ISourceReference) {
                            ISourceRange nameRange = ((ISourceReference) element).getNameRange();
                            result.put("offset", nameRange.getOffset());
                            result.put("length", nameRange.getLength());
                        }

                        return result;
                    }
                    //walk up the java model until we reach a class file
                    while (element != null && !(element instanceof IClassFile)) {
                        element = element.getParent();
                    }

                    if (element instanceof IClassFile) {
                        IClassFile classFile = (IClassFile) element;
                        ISourceRange sourceRange = classFile.getSourceRange();
                        if (sourceRange != null) {
                            String projectName = element.getJavaProject().getProject().getName();
                            String resourcePath = classFile.getParent().getElementName().replace('.', '/');
                            resourcePath = "classpath:/" + resourcePath + "/" + classFile.getElementName();

                            result.put("project", projectName);
                            result.put("resource", resourcePath);

                            return result;
                        }
                    }
                    //we don't know how to navigate to this element
                }
            }

        } catch (JavaModelException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

    public void dispose() {
        messagingConnector.removeMessageHandler(navigationRequestHandler);
    }

}