/**
 * DataCleaner (community edition)
 * Copyright (C) 2014 Neopost - Customer Information Management
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.datacleaner.beans.transform;

import javax.inject.Named;

import org.datacleaner.api.Categorized;
import org.datacleaner.api.Configured;
import org.datacleaner.api.Description;
import org.datacleaner.api.ExpressionBasedInputColumn;
import org.datacleaner.api.Initialize;
import org.datacleaner.api.InputRow;
import org.datacleaner.api.OutputColumns;
import org.datacleaner.api.Transformer;
import org.datacleaner.components.categories.ScriptingCategory;
import org.datacleaner.data.ConstantInputColumn;
import org.datacleaner.data.ELInputColumn;

@Named("Expression language (EL) transformer")
@Description("Generates a column based on an EL expression")
@Categorized({ ScriptingCategory.class })
public class ELTransformer implements Transformer {

    @Configured
    String _expression;

    private ExpressionBasedInputColumn<String> _column;

    @Override
    public OutputColumns getOutputColumns() {
        return new OutputColumns(1, String.class);
    }

    @Initialize
    public void init() {
        // we simply reuse the functionality available in the ELInputColumn
        if (_expression.indexOf("#{") == -1) {
            _column = new ConstantInputColumn(_expression);
        } else {
            _column = new ELInputColumn(_expression);
        }
    }

    @Override
    public String[] transform(final InputRow inputRow) {
        final String result = _column.evaluate(inputRow);
        return new String[] { result };
    }

}