/**
 * 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.datastructures;

import java.util.List;

import javax.inject.Inject;
import javax.inject.Named;

import org.datacleaner.api.Categorized;
import org.datacleaner.api.Configured;
import org.datacleaner.api.Description;
import org.datacleaner.api.InputColumn;
import org.datacleaner.api.InputRow;
import org.datacleaner.api.OutputColumns;
import org.datacleaner.api.OutputRowCollector;
import org.datacleaner.api.Provided;
import org.datacleaner.api.Transformer;
import org.datacleaner.components.categories.DataStructuresCategory;

/**
 * Transformer for extracting elements from lists.
 */
@Named("Read elements from list")
@Description("Reads all elements of a list, creating a record for each value")
@Categorized(DataStructuresCategory.class)
public class ReadFromListTransformer implements Transformer {

    @Inject
    @Configured
    InputColumn<List<?>> listColumn;

    @Inject
    @Configured
    Class<?> elementType;

    @Inject
    @Configured
    @Description("Verify that expected element type and actual type are the same")
    boolean verifyTypes = false;

    @Inject
    @Provided
    OutputRowCollector outputRowCollector;

    public void setElementType(final Class<?> elementType) {
        this.elementType = elementType;
    }

    public void setListColumn(final InputColumn<List<?>> listColumn) {
        this.listColumn = listColumn;
    }

    public void setVerifyTypes(final boolean verifyTypes) {
        this.verifyTypes = verifyTypes;
    }

    @Override
    public OutputColumns getOutputColumns() {
        final String[] columnNames = new String[] { listColumn.getName() + " (element)" };
        final Class<?>[] columnTypes = new Class[] { elementType };
        return new OutputColumns(columnNames, columnTypes);
    }

    @Override
    public Object[] transform(final InputRow row) {
        final List<?> list = row.getValue(listColumn);
        if (list == null || list.isEmpty()) {
            return new Object[1];
        }

        for (Object value : list) {
            if (verifyTypes) {
                value = elementType.cast(value);
            }
            outputRowCollector.putValues(value);
        }

        return null;
    }

}