org.aksw.TripleCheckMate.client.widgets.SparqlSuggestOracle.java Source code

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Here is the source code for org.aksw.TripleCheckMate.client.widgets.SparqlSuggestOracle.java

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/*******************************************************************************
 * Copyright 2013 Agile Knowledge Engineering and Semantic Web (AKSW) Group
 *
 * 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.aksw.TripleCheckMate.client.widgets;

import com.google.gwt.http.client.RequestBuilder;
import com.google.gwt.http.client.RequestException;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.SuggestOracle;
import org.aksw.TripleCheckMate.shared.evaluate.SessionContext;
import org.aksw.TripleCheckMate.shared.sparql.JsonSparqlResult;
import org.aksw.TripleCheckMate.shared.sparql.ResultItem;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

public class SparqlSuggestOracle extends SuggestOracle {

    @Override
    public void requestSuggestions(final Request request, final Callback callback) {
        // TODO Auto-generated method stub
        String addressQuery = request.getQuery();
        // look up for suggestions, only if at least 2 letters have been typed
        if (addressQuery.length() > 2) {
            try {
                String query = SessionContext.endpoint.getQueryforAutocomplete(addressQuery);
                String queryURL = SessionContext.endpoint.generateQueryURL(query);

                RequestBuilder rb = new RequestBuilder(RequestBuilder.GET, queryURL);
                rb.setCallback(new com.google.gwt.http.client.RequestCallback() {

                    public void onResponseReceived(com.google.gwt.http.client.Request req,
                            com.google.gwt.http.client.Response res) {
                        try {
                            JsonSparqlResult result = new JsonSparqlResult(res.getText());
                            Collection<Suggestion> suggestions = new ArrayList<Suggestion>();
                            for (List<ResultItem> i : result.data) {
                                if (i.size() == 1) {
                                    suggestions.add(new SparqlSuggestItem(i.get(0).value));
                                }
                            }

                            callback.onSuggestionsReady(request, new Response(suggestions));
                        } catch (Exception e) {
                            e.printStackTrace();
                            Window.alert("Error communicating with SPARQL Endpoint!");
                        }
                    }

                    public void onError(com.google.gwt.http.client.Request request, Throwable exception) {

                    }
                });
                rb.send();
            } catch (RequestException e) {
                Window.alert("Error occurred" + e.getMessage());
            }

        } else {
            Response response = new Response(Collections.<Suggestion>emptyList());
            callback.onSuggestionsReady(request, response);
        }
    }

    public class SparqlSuggestItem implements SuggestOracle.Suggestion, Serializable {

        private static final long serialVersionUID = 1L;

        public String uri;

        public SparqlSuggestItem(String uri) {
            this.uri = uri;
        }

        public String getDisplayString() {
            return this.uri;
        }

        public String getReplacementString() {
            return this.uri;
        }
    }

}