ee.ioc.phon.netspeechapi.Utils.java Source code

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Here is the source code for ee.ioc.phon.netspeechapi.Utils.java

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/*
 * This file is part of Net Speech API.
 * Copyright 2011, Institute of Cybernetics at Tallinn University of Technology
 *
 * Net Speech API is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * Net Speech API is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with ACE View.
 * If not, see http://www.gnu.org/licenses/.
 */

package ee.ioc.phon.netspeechapi;

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

/**
 * <p>Various static helper methods.</p>
 * 
 * @author Kaarel Kaljurand
 *
 */
public class Utils {

    private Utils() {
    } // no instances allowed

    /**
     * @see #getResponseEntityAsString(HttpClient client, HttpUriRequest request)
     */
    public static String getResponseEntityAsString(HttpUriRequest request) throws IOException {
        return getResponseEntityAsString(new DefaultHttpClient(), request);
    }

    /**
     * <p>Executes the given HTTP request using the given HTTP client,
     * and returns the received entity as string.
     * Returns <code>null</code> if the query was performed (i.e. the server
     * was reachable) but resulted in a failure,
     * e.g. 404 error.</p>
     * 
     * @param client HTTP client
     * @param request HTTP request (e.g. GET or POST)
     * @return response as String
     * @throws IOException
     */
    public static String getResponseEntityAsString(HttpClient client, HttpUriRequest request) throws IOException {
        try {
            HttpResponse response = client.execute(request);
            HttpEntity entity = response.getEntity();

            if (entity == null) {
                return null;
            }
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != HttpStatus.SC_OK) {
                return null;
            }
            if (entity.getContentEncoding() == null) {
                return EntityUtils.toString(entity, HTTP.UTF_8);
            }
            return EntityUtils.toString(entity);
        } finally {
            client.getConnectionManager().shutdown();
        }
    }

    /**
     * <p>Returns <code>true</code> if the given string qualifies as
     * a legal recognizer server response token.
     * We currently check that its length is not bigger than a certain (small) value.</p>
     */
    public static boolean isLegalToken(String token) {
        return (token != null && token.length() < Constants.MAX_TOKEN_LENGTH);
    }
}