ParametersHintsPresenter.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.ext.java.client.navigation.paraminfo;

import com.google.common.base.Optional;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import org.eclipse.che.api.promises.client.Operation;
import org.eclipse.che.api.promises.client.OperationException;
import org.eclipse.che.api.promises.client.PromiseError;
import org.eclipse.che.ide.api.editor.texteditor.TextEditor;
import org.eclipse.che.ide.api.resources.Project;
import org.eclipse.che.ide.api.resources.Resource;
import org.eclipse.che.ide.api.resources.VirtualFile;
import org.eclipse.che.ide.ext.java.client.navigation.service.JavaNavigationService;
import org.eclipse.che.ide.ext.java.client.util.JavaUtil;
import org.eclipse.che.ide.ext.java.shared.dto.model.MethodParameters;
import org.eclipse.che.ide.api.editor.document.Document;
import org.eclipse.che.ide.api.editor.position.PositionConverter;
import org.eclipse.che.ide.util.loging.Log;

import java.util.List;

/**
 * The class contains business logic which calls {@link JavaNavigationService} to get method parameters hints.We can use the class to call
 * service to get parameters hints for particular overloading method.
 *
 * @author Dmitry Shnurenko
 */
@Singleton
public class ParametersHintsPresenter {

    private final JavaNavigationService navigationService;
    private final ParametersHintsView   view;

    @Inject
    public ParametersHintsPresenter(JavaNavigationService navigationService, ParametersHintsView view) {
        this.navigationService = navigationService;
        this.view = view;
    }

    /**
     * The method gets method parameters via {@link JavaNavigationService} and then call special method on view to display them.
     *
     * @param activeEditor
     *         active editor which contains method or constructor for which parameters will be displayed
     */
    public void show(final TextEditor activeEditor) {
        final int offset = activeEditor.getCursorOffset();

        if (!isCursorInRightPlace(activeEditor, offset)) {
            return;
        }

        VirtualFile file = activeEditor.getEditorInput().getFile();

        if (file instanceof Resource) {
            final Optional<Project> project = ((Resource)file).getRelatedProject();
            final int lineStartOffset = getLineStartOffset(activeEditor, offset);

            navigationService.getMethodParametersHints(project.get().getLocation(), JavaUtil.resolveFQN(file), offset, lineStartOffset)
                             .then(new Operation<List<MethodParameters>>() {
                                 @Override
                                 public void apply(List<MethodParameters> parameters) throws OperationException {
                                     if (parameters.isEmpty()) {
                                         return;
                                     }

                                     PositionConverter.PixelCoordinates coordinates =
                                             activeEditor.getPositionConverter().offsetToPixel(offset);

                                     view.show(parameters, coordinates.getX(), coordinates.getY());
                                 }
                             })
                             .catchError(new Operation<PromiseError>() {
                                 @Override
                                 public void apply(PromiseError error) throws OperationException {
                                     Log.error(getClass(), error.getMessage());
                                 }
                             });
        }


    }

    private boolean isCursorInRightPlace(TextEditor activeEditor, int offset) {
        Document document = activeEditor.getDocument();

        int lineIndex = document.getLineAtOffset(offset);
        int nextLineIndex = lineIndex + 1;

        int nextLineStart = document.getLineStart(nextLineIndex);
        String contentRange = activeEditor.getDocument().getContentRange(offset, nextLineStart - offset);

        return contentRange.contains(")");
    }

    private int getLineStartOffset(TextEditor activeEditor, int offset) {
        Document document = activeEditor.getDocument();
        int lineIndex = document.getLineAtOffset(offset);
        return document.getLineStart(lineIndex);
    }
}