dom/src/main/java/org/apache/james/mime4j/field/DateTimeFieldLenientImpl.java

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package org.apache.james.mime4j.field;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;

import org.apache.james.mime4j.codec.DecodeMonitor;
import org.apache.james.mime4j.dom.FieldParser;
import org.apache.james.mime4j.dom.field.DateTimeField;
import org.apache.james.mime4j.stream.Field;

/**
 * Date-time field such as <code>Date</code> or <code>Resent-Date</code>.
 */
public class DateTimeFieldLenientImpl extends AbstractField implements DateTimeField {

    private static final String DEFAULT_DATE_FORMAT = "EEE, dd MMM yyyy hh:mm:ss ZZZZ";

    private final List<String> datePatterns;

    private boolean parsed = false;
    private Date date;

    DateTimeFieldLenientImpl(final Field rawField,
            final Collection<String> dateParsers, final DecodeMonitor monitor) {
        super(rawField, monitor);
        this.datePatterns = new ArrayList<String>();
        if (dateParsers != null) {
            this.datePatterns.addAll(dateParsers);
        } else {
            this.datePatterns.add(DEFAULT_DATE_FORMAT);
        }
    }

    public Date getDate() {
        if (!parsed) {
            parse();
        }
        return date;
    }

    private void parse() {
        parsed = true;
        date = null;
        String body = getBody();
        for (String datePattern: datePatterns) {
            try {
                SimpleDateFormat parser = new SimpleDateFormat(datePattern, Locale.US);
                parser.setTimeZone(TimeZone.getTimeZone("GMT"));
                parser.setLenient(true);
                date = parser.parse(body);
                break;
            } catch (ParseException ignore) {
            }
        }
    }

    public static final FieldParser<DateTimeField> PARSER = new FieldParser<DateTimeField>() {

        public DateTimeField parse(final Field rawField, final DecodeMonitor monitor) {
            return new DateTimeFieldLenientImpl(rawField, null, monitor);
        }

    };
}