arces.unibo.SEPA.commons.SPARQL.Bindings.java Source code

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Here is the source code for arces.unibo.SEPA.commons.SPARQL.Bindings.java

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/* This class represents a query solution of a SPARQL 1.1 Query
 * 
 * Author: Luca Roffia (luca.roffia@unibo.it)
    
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
This program 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 General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package arces.unibo.SEPA.commons.SPARQL;

import java.util.HashSet;
import java.util.Map.Entry;
import java.util.Set;

import com.google.gson.JsonElement;
import com.google.gson.JsonObject;

/**
 * This class represents a query solution of a SPARQL 1.1 Query
 * 
 * An example of the internal representation as JSON object follows:
 * 
 * {
 *       "x" :       { 
 *                   "type": "bnode", 
 *                   "value": "r2" 
 *                },
 *      "hpage" :    {   
 *                  "type": "uri", 
 *                  "value": "http://work.example.org/alice/" 
 *               },
 *       "blurb" :    {
 *                   "datatype": "http://www.w3.org/1999/02/22-rdf-syntax-ns#XMLLiteral",
 *                   "type": "literal",
 *                   "value": "<p xmlns=\"http://www.w3.org/1999/xhtml\">My name is <b>alice</b></p>"
 *                },
 *       "name" :    { 
 *                   "type": "literal", 
 *                   "value": "Bob", 
 *                   "xml:lang": "en" 
 *                }
 *    }
 *             
 * @author Luca Roffia (luca.roffia@unibo.it)
 * @version 0.1
 */

public class Bindings {
    private JsonObject solution;

    public Bindings(JsonObject solution) {
        this.solution = solution;
    }

    public Bindings() {
        solution = new JsonObject();
    }

    public Set<String> getVariables() {
        Set<String> ret = new HashSet<String>();
        for (Entry<String, JsonElement> entry : solution.entrySet()) {
            ret.add(entry.getKey());
        }
        return ret;
    }

    public String getBindingValue(String variable) {
        if (solution.get(variable) == null)
            return null;
        JsonObject json = solution.get(variable).getAsJsonObject();
        return json.get("value").getAsString();
    }

    public String getDatatype(String variable) {
        if (solution.get(variable) == null)
            return null;
        JsonObject json = solution.get(variable).getAsJsonObject();
        if (json.get("datatype") == null)
            return null;
        return json.get("datatype").getAsString();
    }

    public String getLanguage(String variable) {
        if (solution.get(variable) == null)
            return null;
        JsonObject json = solution.get(variable).getAsJsonObject();
        if (json.get("xml:lang") == null)
            return null;
        return json.get("xml:lang").getAsString();
    }

    public boolean isLiteral(String variable) {
        if (solution.get(variable) == null)
            return false;
        JsonObject json = solution.get(variable).getAsJsonObject();
        return json.get("type").getAsString().equals("literal");
    }

    public boolean isURI(String variable) {
        if (solution.get(variable) == null)
            return false;
        JsonObject json = solution.get(variable).getAsJsonObject();
        return json.get("type").getAsString().equals("uri");
    }

    public boolean isBNode(String variable) {
        if (solution.get(variable) == null)
            return false;
        JsonObject json = solution.get(variable).getAsJsonObject();
        return json.get("type").getAsString().equals("bnode");
    }

    public void addBinding(String variable, RDFTerm value) {
        solution.add(variable, value.toJson());
    }

    public boolean equals(Bindings qs) {
        return this.solution.equals(qs.solution);
    }

    public JsonObject toJson() {
        return solution;
    }

    public String toString() {
        return solution.toString();
    }

    public boolean isEmpty() {
        return solution.isJsonNull();
    }
}