DateParser.java

/*
 * Licensed to STRATIO (C) under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership.  The STRATIO (C) 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.
 */

package com.stratio.cassandra.lucene.util;

import com.stratio.cassandra.lucene.IndexException;
import org.apache.cassandra.utils.UUIDGen;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;

/**
 * Unified class for parse a {@link Date}s from {@link Object}s including a {@code String} pattern.
 *
 * @author Eduardo Alonso {@literal <eduardoalonso@stratio.com>}
 */
public class DateParser {

    /** The default date pattern for {@code String}s. */
    public static final String DEFAULT_PATTERN = "yyyy/MM/dd HH:mm:ss.SSS Z";

    /** The pattern value for timestamps. */
    public static final String TIMESTAMP_PATTERN_FIELD = "timestamp";

    private static final Long DAYS_TO_MILLIS = 24L * 60L * 60L * 1000L;

    /** The {@link SimpleDateFormat} pattern. */
    private final String pattern;

    /** The thread safe date format. */
    private final ThreadLocal<DateFormat> concurrentDateFormat;

    /**
     * Constructor with pattern.
     *
     * @param pattern the {@link SimpleDateFormat} pattern to use
     */
    public DateParser(String pattern) {

        this.pattern = pattern == null ? DEFAULT_PATTERN : pattern;

        // Validate pattern if is not "timestamp"
        if (!this.pattern.equals(TIMESTAMP_PATTERN_FIELD)) {
            new SimpleDateFormat(this.pattern);
            this.concurrentDateFormat = new ThreadLocal<DateFormat>() {
                @Override
                protected DateFormat initialValue() {
                    return new SimpleDateFormat(DateParser.this.pattern);
                }
            };
            this.concurrentDateFormat.get().setLenient(false);
        } else {
            this.concurrentDateFormat = null;
        }
    }

    /**
     * Returns the {@link Date} represented by the specified {@link Object}, or {@code null} if the specified  {@link
     * Object} is {@code null}.
     *
     * @param value the {@link Object} to be parsed
     * @return the parsed {@link Date}
     */
    public Date parse(Object value) {
        if (value == null) {
            return null;
        } else if (value instanceof Date) {
            return (Date) value;
        } else if (value instanceof Integer) {
            if ((Integer) value < 0) {
                throw new IndexException("Required positive Integer for dates but found '%s'", value);
            } else {
                return new Date(DAYS_TO_MILLIS * (Integer) value);
            }
        } else if (value instanceof Long) {
            if ((Long) value < 0L) {
                throw new IndexException("Required positive Long for dates but found '%s'", value);
            } else {
                return new Date((Long) value);
            }
        } else if (value instanceof UUID) {
            try {
                return new Date(UUIDGen.unixTimestamp((UUID) value));
            } catch (UnsupportedOperationException e) {
                throw new IndexException("Required a version 1 UUID but found '%s'", value);
            }
        } else {
            if (pattern.equals(TIMESTAMP_PATTERN_FIELD)) {
                return parseAsTimestamp(value);
            } else {
                return parseAsFormattedDate(value);
            }
        }
    }

    private Date parseAsTimestamp(Object value) {
        Long valueLong;
        if (value instanceof Number) {
            valueLong = ((Number) value).longValue();
        } else {
            try {
                valueLong = Long.parseLong((value).toString());
            } catch (NumberFormatException e) {
                valueLong = null;
            }
        }
        if (valueLong != null) {
            return new Date(valueLong);
        } else {
            throw new IndexException("Valid timestamp required but found '%s'", value);
        }
    }

    private Date parseAsFormattedDate(Object value) {
        try {
            return concurrentDateFormat.get().parse(value.toString());
        } catch (ParseException e) {
            throw new IndexException("Required date with pattern '%s' but found '%s'", pattern, value);
        }
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return pattern;
    }

    /**
     * Returns the {@link String} representation of the specified {@link Date}.
     *
     * @param date the date
     * @return the {@link String} representation of {@code Date}
     */
    public String toString(Date date) {
        if (pattern.equals(TIMESTAMP_PATTERN_FIELD)) {
            return ((Long) date.getTime()).toString();
        } else {
            return concurrentDateFormat.get().format(date);
        }
    }
}