com.microsoft.research.webngram.service.impl.LookupServiceImpl.java Source code

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Here is the source code for com.microsoft.research.webngram.service.impl.LookupServiceImpl.java

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/*
 * Copyright 2011 Nabeel Mukhtar 
 * 
 * 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.microsoft.research.webngram.service.impl;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.json.JSONArray;

import com.microsoft.research.webngram.service.LookupService;
import com.microsoft.research.webngram.service.constant.NgramServiceApiUrls;
import com.microsoft.research.webngram.service.constant.ParameterNames;
import com.microsoft.research.webngram.service.constant.NgramServiceApiUrls.NgramServiceApiUrlBuilder;
import com.microsoft.research.webngram.service.exception.NgramServiceException;

/**
 * The Class LookupServiceImpl.
 */
public class LookupServiceImpl extends BaseNgramService implements LookupService {

    /**
     * Instantiates a new lookup service impl.
     * 
     * @param applicationId the application id
     */
    public LookupServiceImpl(String applicationId) {
        super(applicationId);
    }

    /* (non-Javadoc)
     * @see com.microsoft.research.webngram.service.LookupService#getConditionalProbabilities(java.lang.String, java.lang.String, java.util.List)
     */
    @Override
    public List<Double> getConditionalProbabilities(String authorizationToken, String modelUrn,
            List<String> phrases) {
        try {
            List<Double> probabilities = new ArrayList<Double>();
            NgramServiceApiUrlBuilder urlBuilder = createNgramServiceApiUrlBuilder(
                    NgramServiceApiUrls.GET_CONDITIONAL_PROBABILITIES_URL);
            String apiUrl = urlBuilder.withField(ParameterNames.MODEL_URL, modelUrn)
                    .withParameter(ParameterNames.USER_TOKEN, authorizationToken).buildUrl();
            JSONArray array = new JSONArray(
                    convertStreamToString(callApiMethod(apiUrl, getPostBody(phrases), null, "POST", 200)));
            for (int i = 0; i < array.length(); i++) {
                probabilities.add(array.getDouble(i));
            }
            return probabilities;
        } catch (Exception e) {
            throw new NgramServiceException("An error occurred while getting conditional probabilities.", e);
        }
    }

    /* (non-Javadoc)
     * @see com.microsoft.research.webngram.service.LookupService#getConditionalProbability(java.lang.String, java.lang.String, java.lang.String)
     */
    @Override
    public Double getConditionalProbability(String authorizationToken, String modelUrn, String phrase) {
        NgramServiceApiUrlBuilder urlBuilder = createNgramServiceApiUrlBuilder(
                NgramServiceApiUrls.GET_CONDITIONAL_PROBABILITIES_URL);
        String apiUrl = urlBuilder.withParameter(ParameterNames.USER_TOKEN, authorizationToken)
                .withField(ParameterNames.MODEL_URL, modelUrn).withParameter(ParameterNames.PHRASE, phrase)
                .buildUrl();
        return Double.parseDouble(convertStreamToString(callApiGet(apiUrl)));
    }

    /* (non-Javadoc)
     * @see com.microsoft.research.webngram.service.LookupService#getModels()
     */
    @Override
    public List<String> getModels() {
        try {
            List<String> models = new ArrayList<String>();
            NgramServiceApiUrlBuilder urlBuilder = createNgramServiceApiUrlBuilder(NgramServiceApiUrls.LOOKUP_URL);
            String apiUrl = urlBuilder.buildUrl();
            JSONArray array = new JSONArray(convertStreamToString(callApiGet(apiUrl)));
            for (int i = 0; i < array.length(); i++) {
                models.add(array.getString(i));
            }
            return models;
        } catch (Exception e) {
            throw new NgramServiceException("An error occurred while getting models.", e);
        }
    }

    /* (non-Javadoc)
     * @see com.microsoft.research.webngram.service.LookupService#getProbabilities(java.lang.String, java.lang.String, java.util.List)
     */
    @Override
    public List<Double> getProbabilities(String authorizationToken, String modelUrn, List<String> phrases) {
        try {
            List<Double> probabilities = new ArrayList<Double>();
            NgramServiceApiUrlBuilder urlBuilder = createNgramServiceApiUrlBuilder(
                    NgramServiceApiUrls.GET_PROBABILITIES_URL);
            String apiUrl = urlBuilder.withField(ParameterNames.MODEL_URL, modelUrn)
                    .withParameter(ParameterNames.USER_TOKEN, authorizationToken).buildUrl();
            JSONArray array = new JSONArray(
                    convertStreamToString(callApiMethod(apiUrl, getPostBody(phrases), null, "POST", 200)));
            for (int i = 0; i < array.length(); i++) {
                probabilities.add(array.getDouble(i));
            }
            return probabilities;
        } catch (Exception e) {
            throw new NgramServiceException("An error occurred while getting probabilities.", e);
        }
    }

    /* (non-Javadoc)
     * @see com.microsoft.research.webngram.service.LookupService#getProbability(java.lang.String, java.lang.String, java.lang.String)
     */
    @Override
    public Double getProbability(String authorizationToken, String modelUrn, String phrase) {
        NgramServiceApiUrlBuilder urlBuilder = createNgramServiceApiUrlBuilder(
                NgramServiceApiUrls.GET_PROBABILITIES_URL);
        String apiUrl = urlBuilder.withParameter(ParameterNames.USER_TOKEN, authorizationToken)
                .withField(ParameterNames.MODEL_URL, modelUrn).withParameter(ParameterNames.PHRASE, phrase)
                .buildUrl();
        return Double.parseDouble(convertStreamToString(callApiGet(apiUrl)));
    }

    /**
     * Gets the post body.
     * 
     * @param phrases the phrases
     * 
     * @return the post body
     */
    private String getPostBody(List<String> phrases) {
        StringBuilder builder = new StringBuilder();
        for (Iterator<String> iterator = phrases.iterator(); iterator.hasNext();) {
            builder.append(iterator.next());
            if (iterator.hasNext()) {
                builder.append("\n");
            }
        }
        return builder.toString();
    }
}