com.googlecodesamples.FusionTablesAccessor.java Source code

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Here is the source code for com.googlecodesamples.FusionTablesAccessor.java

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/*
 * Copyright 2009 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.googlecodesamples;

import com.google.api.client.auth.oauth2.BearerToken;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.auth.oauth2.CredentialRefreshListener;
import com.google.api.client.googleapis.auth.oauth2.GoogleOAuthConstants;
import com.google.api.client.http.HttpExecuteInterceptor;
import com.google.api.client.http.HttpRequest;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.services.fusiontables.Fusiontables;

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

/**
 * Returns Fusiontables API handle for {@link OAuth2Tokens}.
 *
 * @author googletables-feedback@google.com (Anno Langen)
 */
public class FusionTablesAccessor {

    public static final HttpTransport HTTP_TRANSPORT = new NetHttpTransport();
    public static final JacksonFactory JSON_FACTORY = new JacksonFactory();

    // Refresh tokens require a non-null client authentication instance.
    public static final HttpExecuteInterceptor NOOP_CLIENT_AUTHENTICATION = new HttpExecuteInterceptor() {
        public void intercept(HttpRequest request) throws IOException {
        }
    };

    /**
     * Returns Fusiontables API handle for {@link OAuth2Tokens}.
     */
    public static Fusiontables getFusiontables(OAuth2Tokens tokens) throws IOException {
        return new Fusiontables.Builder(HTTP_TRANSPORT, JSON_FACTORY, getCredential(tokens))
                // Shuts up warning from AbstractGoogleClient.
                .setApplicationName("snippet").build();
    }

    /**
     * Builds a Credential for use with the Fusiontables client API from {@link OAuth2Tokens}.
     */
    // This is non-obvious because the API is tailored for online access, where the user's
    // authorization is tied to the session and a new access token can be fetched with redirects. The
    // snippet application requires ``offline'' access where a table owner can sanction
    // unauthenticated access to a snippet of their private table. Offline access is evidently rare
    // for web applications and explains the need for registering the OAuth2Tokens instance as a
    // refresh listener. When the access token is about to expire a new refresh token is requested and
    // made available through a listener interface.
    private static Credential getCredential(OAuth2Tokens tokens) throws IOException {
        return newCredentialBuilder(tokens).build().setFromTokenResponse(tokens.toTokenResponse());
    }

    private static Credential.Builder newCredentialBuilder(final OAuth2Tokens tokens) {
        return new Credential.Builder(BearerToken.authorizationHeaderAccessMethod()).setTransport(HTTP_TRANSPORT)
                .setJsonFactory(JSON_FACTORY).setClientAuthentication(NOOP_CLIENT_AUTHENTICATION)
                .setRefreshListeners(Collections.<CredentialRefreshListener>singleton(tokens))
                .setTokenServerEncodedUrl(GoogleOAuthConstants.TOKEN_SERVER_URL);
    }
}