org.dataconservancy.dcs.access.client.HttpGet.java Source code

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Here is the source code for org.dataconservancy.dcs.access.client.HttpGet.java

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/*
 * Copyright 2012 Johns Hopkins University
 *
 * 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 org.dataconservancy.dcs.access.client;

import com.google.gwt.http.client.Request;
import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestCallback;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.http.client.Response;

public class HttpGet {
    public interface Callback<T> {
        void success(T result);

        void failure(String error);
    }

    /**
     * Do multiple http requests and only return success when all complete. May
     * be more than one failure reported.
     * 
     * cb.success returns a String[] parallel to urls with the results
     * 
     * @param urls
     * @param cb
     */
    public static void request(final String[] urls, final Callback<String[]> cb) {
        final String[] result = new String[urls.length];

        for (int i = 0; i < urls.length; i++) {
            RequestBuilder rb = new RequestBuilder(RequestBuilder.GET, urls[i]);
            final int which = i;

            try {
                rb.sendRequest(null, new RequestCallback() {
                    public void onError(Request req, Throwable e) {
                        cb.failure(e.getMessage());
                    }

                    public void onResponseReceived(Request req, Response resp) {
                        if (resp.getStatusCode() != 200) {
                            cb.failure(resp.getText());
                        } else {
                            result[which] = resp.getText();

                            for (int j = 0; j < result.length; j++) {
                                if (result[j] == null) {
                                    return;
                                }
                            }

                            cb.success(result);
                        }
                    }
                });
            } catch (RequestException e) {
                cb.failure(e.getMessage());
            }
        }
    }

    public static void request(final String url, final Callback<String> cb) {
        RequestBuilder rb = new RequestBuilder(RequestBuilder.GET, url);

        try {
            rb.sendRequest(null, new com.google.gwt.http.client.RequestCallback() {
                public void onError(Request req, Throwable e) {
                    cb.failure(e.getMessage());
                }

                public void onResponseReceived(Request req, Response resp) {
                    if (resp.getStatusCode() != 200) {
                        cb.failure(resp.getText());
                    } else {
                        cb.success(resp.getText());
                    }
                }
            });
        } catch (RequestException e) {
            cb.failure(e.getMessage());
        }
    }
}