D-Net

package eu.dnetlib.utils.cql;

import java.io.IOException;

import java.io.StringReader;

import org.antlr.runtime.ANTLRReaderStream;

import org.antlr.runtime.CommonTokenStream;

import org.antlr.runtime.RecognitionException;

/**

 * @author stoumpos

 * 

 */

public class Cql {

	/**

	 * Parse cql query in <code>text</code> and return the respective cql

	 * query object.

	 * 

	 * @param text

	 *            The cql text.

	 * @return The cql tree object.

	 */

	public static CqlQuery parse(String text) throws CqlException {

		try {

			StringReader reader = new StringReader(text);

			ANTLRReaderStream input = new ANTLRReaderStream(reader);

			CqlLexer lexer = new CqlLexer(input);

			CommonTokenStream tokens = new CommonTokenStream(lexer);

			CqlParser parser = new CqlParser(tokens);

			CqlQuery query = parser.cql().query;

			return query;

		} catch (IOException ioe) {

			throw new CqlException("Error building cql parser.", ioe);

		} catch (RecognitionException re) {

			throw new CqlException("Error parsing cql query.", re);

		} catch (CqlRuntimeException cre) {

			throw new CqlException("Error parsing cql query.", cre.getCause());			

		}

	}

	/**

	 * Writes <code>query</code> as string. The same functionality is possible

	 * through {@link CqlQuery#toString()}.

	 * 

	 * @param query

	 * @return

	 */

	public static String encode(CqlQuery query) {

		return query.toString();

	}

}