package org.apache.fulcrum.parser;


/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */


import java.io.Reader;
import java.io.StreamTokenizer;
import java.util.List;

/**
 * CSVParser is used to parse a stream with comma-separated values and
 * generate ParameterParser objects which can be used to
 * extract the values in the desired type.
 *
 * <p>The class extends the abstract class DataStreamParser and implements
 * initTokenizer with suitable values for CSV files to provide this
 * functionality.
 *
 * <p>The class (indirectly through DataStreamParser) implements the
 * java.util.Iterator interface for convenience.
 * This allows simple use in a Velocity template for example:
 *
 * <pre>
 * #foreach ($row in $csvfile)
 *   Name: $row.Name
 *   Description: $row.Description
 * #end
 * </pre>
 *
 * @author <a href="mailto:sean@informage.net">Sean Legassick</a>
 * @version $Id$
 */
public class CSVParser extends DataStreamParser
{
    /**
     * Create a new CSVParser instance. Requires a Reader to read the
     * comma-separated values from. The column headers must be set
     * independently either explicitly, or by reading the first line
     * of the CSV values.
     *
     * @param in the input reader.
     */
    public CSVParser(Reader in)
    {
        super(in, null, null);
    }

    /**
     * Create a new CSVParser instance. Requires a Reader to read the
     * comma-separated values from, and a list of column names.
     *
     * @param in the input reader.
     * @param columnNames a list of column names.
     */
    public CSVParser(Reader in, List<String> columnNames)
    {
        super(in, columnNames, null);
    }

    /**
     * Create a new CSVParser instance. Requires a Reader to read the
     * comma-separated values from, a list of column names and a
     * character encoding.
     *
     * @param in the input reader.
     * @param columnNames a list of column names.
     * @param characterEncoding the character encoding of the input.
     */
    public CSVParser(Reader in, List<String> columnNames, String characterEncoding)
    {
        super(in, columnNames, characterEncoding);
    }

    /**
     * Initialize the StreamTokenizer instance used to read the lines
     * from the input reader.
     */
    protected void initTokenizer(StreamTokenizer tokenizer)
    {
        // set all numeric characters as ordinary characters
        // (switches off number parsing)
        tokenizer.ordinaryChars('0', '9');
        tokenizer.ordinaryChars('-', '-');
        tokenizer.ordinaryChars('.', '.');

        // set all printable characters to be treated as word chars
        tokenizer.wordChars(' ', Integer.MAX_VALUE);

        // now set comma as the whitespace character
        tokenizer.whitespaceChars(',', ',');

        // and  set the quote mark as the quoting character
        tokenizer.quoteChar('"');

        // and finally say that end of line is significant
        tokenizer.eolIsSignificant(true);
    }
}