LanguageServerSignatureHelp.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.plugin.languageserver.ide.editor.signature;

import com.google.common.base.Optional;
import com.google.inject.Inject;
import com.google.inject.assistedinject.Assisted;
import com.google.web.bindery.event.shared.HandlerRegistration;

import org.eclipse.che.api.promises.client.Function;
import org.eclipse.che.api.promises.client.FunctionException;
import org.eclipse.che.api.promises.client.Promise;
import org.eclipse.che.api.promises.client.PromiseError;
import org.eclipse.che.ide.api.editor.document.Document;
import org.eclipse.che.ide.api.editor.events.DocumentChangeEvent;
import org.eclipse.che.ide.api.editor.events.DocumentChangeHandler;
import org.eclipse.che.ide.api.editor.signature.SignatureHelp;
import org.eclipse.che.ide.api.editor.signature.SignatureHelpProvider;
import org.eclipse.che.ide.api.editor.texteditor.HandlesTextOperations;
import org.eclipse.che.ide.api.editor.texteditor.TextEditor;
import org.eclipse.che.ide.api.editor.texteditor.TextEditorOperations;
import org.eclipse.che.ide.api.notification.NotificationManager;
import org.eclipse.che.ide.api.notification.StatusNotification;
import org.eclipse.che.plugin.languageserver.ide.service.TextDocumentServiceClient;
import org.eclipse.che.plugin.languageserver.ide.util.DtoBuildHelper;
import org.eclipse.lsp4j.ServerCapabilities;
import org.eclipse.lsp4j.TextDocumentPositionParams;

import java.util.List;

/**
 * LS implementation for Signature help feature
 *
 * @author Evgen Vidolob
 */
public class LanguageServerSignatureHelp implements SignatureHelpProvider {

    private final TextDocumentServiceClient client;
    private final DtoBuildHelper            helper;
    private final NotificationManager       notificationManager;
    private final ServerCapabilities        capabilities;
    private       HandlerRegistration       handlerRegistration;

    @Inject
    public LanguageServerSignatureHelp(TextDocumentServiceClient client,
                                       DtoBuildHelper helper,
                                       NotificationManager notificationManager,
                                       @Assisted ServerCapabilities capabilities) {
        this.client = client;
        this.helper = helper;
        this.notificationManager = notificationManager;
        this.capabilities = capabilities;
    }

    @Override
    public Promise<Optional<SignatureHelp>> signatureHelp(Document document, int offset) {
        TextDocumentPositionParams paramsDTO = helper.createTDPP(document, offset);
        Promise<org.eclipse.lsp4j.SignatureHelp> promise = client.signatureHelp(paramsDTO);
        return promise.then(new Function<org.eclipse.lsp4j.SignatureHelp, Optional<SignatureHelp>>() {
            @Override
            public Optional<SignatureHelp> apply(org.eclipse.lsp4j.SignatureHelp arg) throws FunctionException {
                if (arg == null) {
                    return Optional.absent();
                }

                return Optional.<SignatureHelp>of(new SignatureHelpImpl(arg));
            }
        }).catchError(new Function<PromiseError, Optional<SignatureHelp>>() {
            @Override
            public Optional<SignatureHelp> apply(PromiseError arg) throws FunctionException {
                notificationManager.notify(arg.getMessage(), StatusNotification.Status.FAIL, StatusNotification.DisplayMode.EMERGE_MODE);
                return Optional.absent();
            }
        });
    }

    @Override
    public void install(final TextEditor editor) {
        if (capabilities.getSignatureHelpProvider() != null && capabilities.getSignatureHelpProvider().getTriggerCharacters() != null) {
            final List<String> triggerCharacters = capabilities.getSignatureHelpProvider().getTriggerCharacters();
            handlerRegistration = editor.getDocument().getDocumentHandle().getDocEventBus()
                                        .addHandler(DocumentChangeEvent.TYPE, new DocumentChangeHandler() {
                                            @Override
                                            public void onDocumentChange(DocumentChangeEvent event) {
                                                if (triggerCharacters.contains(event.getText())) {
                                                    ((HandlesTextOperations)editor)
                                                            .doOperation(TextEditorOperations.SIGNATURE_HELP);
                                                }
                                            }
                                        });
        }
    }

    @Override
    public void uninstall() {
        if (handlerRegistration != null) {
            handlerRegistration.removeHandler();
        }
    }
}