com.telegenda.presentation.Utils.java Source code

Introduction

Here is the source code for com.telegenda.presentation.Utils.java

Source

/*
 * Copyright (c) 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.telegenda.presentation;

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.appengine.datastore.AppEngineDataStoreFactory;
import com.google.api.client.extensions.appengine.http.UrlFetchTransport;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.http.GenericUrl;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.Preconditions;
import com.google.api.client.util.store.DataStoreFactory;
import com.google.api.services.calendar.Calendar;
import com.google.api.services.calendar.CalendarScopes;
import com.google.appengine.api.users.UserServiceFactory;

import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Collections;

import javax.servlet.http.HttpServletRequest;

/**
 * Utility class for JDO persistence, OAuth flow helpers, and others.
 *
 * @author Yaniv Inbar
 */
class Utils {

    /**
     * Global instance of the {@link DataStoreFactory}. The best practice is to make it a single
     * globally shared instance across your application.
     */
    private static final AppEngineDataStoreFactory DATA_STORE_FACTORY = AppEngineDataStoreFactory
            .getDefaultInstance();

    /** Global instance of the HTTP transport. */
    static final HttpTransport HTTP_TRANSPORT = new UrlFetchTransport();

    /** Global instance of the JSON factory. */
    static final JsonFactory JSON_FACTORY = JacksonFactory.getDefaultInstance();

    private static GoogleClientSecrets clientSecrets = null;

    static GoogleClientSecrets getClientCredential() throws IOException {
        if (clientSecrets == null) {
            clientSecrets = GoogleClientSecrets.load(JSON_FACTORY,
                    new InputStreamReader(Utils.class.getResourceAsStream("/client_secrets.json")));
            Preconditions.checkArgument(
                    !clientSecrets.getDetails().getClientId().startsWith("Enter ")
                            && !clientSecrets.getDetails().getClientSecret().startsWith("Enter "),
                    "Download client_secrets.json file from https://code.google.com/apis/console/"
                            + "?api=calendar into calendar-appengine-sample/src/main/resources/client_secrets.json");
        }
        return clientSecrets;
    }

    static String getRedirectUri(HttpServletRequest req) {
        GenericUrl url = new GenericUrl(req.getRequestURL().toString());
        url.setRawPath("/oauth2callback");
        return url.build();
    }

    static GoogleAuthorizationCodeFlow newFlow() throws IOException {

        return new GoogleAuthorizationCodeFlow.Builder(HTTP_TRANSPORT, JSON_FACTORY, getClientCredential(),
                Collections.singleton(CalendarScopes.CALENDAR)).setDataStoreFactory(DATA_STORE_FACTORY)
                        .setAccessType("offline").build();
    }

    static Calendar loadCalendarClient() throws IOException {
        String userId = UserServiceFactory.getUserService().getCurrentUser().getUserId();
        Credential credential = newFlow().loadCredential(userId);
        return new Calendar.Builder(HTTP_TRANSPORT, JSON_FACTORY, credential)
                .setApplicationName("telegenda-webservice").build();
    }

    /**
     * Returns an {@link IOException} (but not a subclass) in order to work around restrictive GWT
     * serialization policy.
     */
    static IOException wrappedIOException(IOException e) {
        if (e.getClass() == IOException.class) {
            return e;
        }
        return new IOException(e.getMessage());
    }

    private Utils() {
    }
}