Translate.java

/*
 * microsoft-translator-java-api
 *
 * Copyright 2012 Jonathan Griggs <jonathan.griggs at gmail.com>.
 *
 * 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.memetix.mst;

import java.net.URL;
import java.net.URLEncoder;

/**
 * Translate
 *
 * Makes calls to the Microsoft Translator API /Translate service
 *
 * Uses the AJAX Interface V2 - see:
 * http://msdn.microsoft.com/en-us/library/ff512406.aspx
 *
 * @author Jonathan Griggs <jonathan.griggs at gmail.com>
 */
public final class Translate extends MicrosoftTranslatorAPI {

    private static final String SERVICE_URL = "http://api.microsofttranslator.com/V2/Ajax.svc/Translate?";
    private static final String ARRAY_SERVICE_URL = "http://api.microsofttranslator.com/V2/Ajax.svc/TranslateArray?";
    private static final String ARRAY_JSON_OBJECT_PROPERTY = "TranslatedText";

    //prevent instantiation
    private Translate() {
    }

    ;

    /**
     * Translates text from a given Language to another given Language using Microsoft Translator.
     *
     * @param text The String to translate.
     * @param from The language code to translate from.
     * @param to The language code to translate to.
     * @return The translated String.
     * @throws Exception on error.
     */
    public static String execute(final String text, final Language from, final Language to) throws Exception {
        //Run the basic service validations first
        validateServiceState(text);
        final String params
                = (apiKey != null ? PARAM_APP_ID + URLEncoder.encode(apiKey, ENCODING) : "")
                + PARAM_FROM_LANG + URLEncoder.encode(from.toString(), ENCODING)
                + PARAM_TO_LANG + URLEncoder.encode(to.toString(), ENCODING)
                + PARAM_TEXT_SINGLE + URLEncoder.encode(text, ENCODING);

        final URL url = new URL(SERVICE_URL + params);
        final String response = retrieveString(url);
        return response;
    }

    /**
     * Translates text from a given Language to another given Language using
     * Microsoft Translator.
     *
     * Default the from to AUTO_DETECT
     *
     * @param text The String to translate.
     * @param to The language code to translate to.
     * @return The translated String.
     * @throws Exception on error.
     */
    public static String execute(final String text, final Language to) throws Exception {
        return execute(text, Language.AUTO_DETECT, to);
    }

    /**
     * Translates an array of texts from a given Language to another given
     * Language using Microsoft Translator's TranslateArray service
     *
     * Note that the Microsoft Translator expects all source texts to be of the
     * SAME language.
     *
     * @param texts The Strings Array to translate.
     * @param from The language code to translate from.
     * @param to The language code to translate to.
     * @return The translated Strings Array[].
     * @throws Exception on error.
     */
    public static String[] execute(final String[] texts, final Language from, final Language to) throws Exception {
        //Run the basic service validations first
        validateServiceState(texts);
        final String params
                = (apiKey != null ? PARAM_APP_ID + URLEncoder.encode(apiKey, ENCODING) : "")
                + PARAM_FROM_LANG + URLEncoder.encode(from.toString(), ENCODING)
                + PARAM_TO_LANG + URLEncoder.encode(to.toString(), ENCODING)
                + PARAM_TEXT_ARRAY + URLEncoder.encode(buildStringArrayParam(texts), ENCODING);

        final URL url = new URL(ARRAY_SERVICE_URL + params);
        final String[] response = retrieveStringArr(url, ARRAY_JSON_OBJECT_PROPERTY);
        return response;
    }

    /**
     * Translates an array of texts from an Automatically detected language to
     * another given Language using Microsoft Translator's TranslateArray
     * service
     *
     * Note that the Microsoft Translator expects all source texts to be of the
     * SAME language.
     *
     * This is an overloaded convenience method that passes Language.AUTO_DETECT
     * as fromLang to execute(texts[],fromLang,toLang)
     *
     * @param texts The Strings Array to translate.
     * @param to The language code to translate to.
     * @return The translated Strings Array[].
     * @throws Exception on error.
     */
    public static String[] execute(final String[] texts, final Language to) throws Exception {
        return execute(texts, Language.AUTO_DETECT, to);
    }

    private static void validateServiceState(final String[] texts) throws Exception {
        int length = 0;
        for (String text : texts) {
            length += text.getBytes(ENCODING).length;
        }
        if (length > 10240) {
            throw new RuntimeException("TEXT_TOO_LARGE - Microsoft Translator (Translate) can handle up to 10,240 bytes per request");
        }
        validateServiceState();
    }

    private static void validateServiceState(final String text) throws Exception {
        final int byteLength = text.getBytes(ENCODING).length;
        if (byteLength > 10240) {
            throw new RuntimeException("TEXT_TOO_LARGE - Microsoft Translator (Translate) can handle up to 10,240 bytes per request");
        }
        validateServiceState();
    }
}