cassandra-trunk/src/java/org/apache/cassandra/db/marshal/TimestampType.java
/*
 * 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.
 */
package org.apache.cassandra.db.marshal;

import java.nio.ByteBuffer;
import java.util.Date;

import org.apache.cassandra.cql3.Constants;
import org.apache.cassandra.cql3.Duration;
import org.apache.cassandra.cql3.Term;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.cql3.CQL3Type;
import org.apache.cassandra.serializers.TypeSerializer;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.serializers.TimestampSerializer;
import org.apache.cassandra.transport.ProtocolVersion;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.bytecomparable.ByteComparable;
import org.apache.cassandra.utils.bytecomparable.ByteSource;
import org.apache.cassandra.utils.bytecomparable.ByteSourceInverse;

import static org.apache.cassandra.cql3.statements.RequestValidations.invalidRequest;

/**
 * Type for date-time values.
 *
 * This is meant as a replacement for DateType, as DateType wrongly compare
 * pre-unix-epoch dates, sorting them *after* post-unix-epoch ones (due to it's
 * use of unsigned bytes comparison).
 */
public class TimestampType extends TemporalType<Date>
{
    private static final Logger logger = LoggerFactory.getLogger(TimestampType.class);

    public static final TimestampType instance = new TimestampType();

    private static final ByteBuffer MASKED_VALUE = instance.decompose(new Date(0));

    private TimestampType() {super(ComparisonType.CUSTOM);} // singleton

    public boolean isEmptyValueMeaningless()
    {
        return true;
    }

    public <VL, VR> int compareCustom(VL left, ValueAccessor<VL> accessorL, VR right, ValueAccessor<VR> accessorR)
    {
        return LongType.compareLongs(left, accessorL, right, accessorR);
    }

    @Override
    public <V> ByteSource asComparableBytes(ValueAccessor<V> accessor, V data, ByteComparable.Version version)
    {
        return ByteSource.optionalSignedFixedLengthNumber(accessor, data);
    }

    @Override
    public <V> V fromComparableBytes(ValueAccessor<V> accessor, ByteSource.Peekable comparableBytes, ByteComparable.Version version)
    {
        return ByteSourceInverse.getOptionalSignedFixedLength(accessor, comparableBytes, 8);
    }

    public ByteBuffer fromString(String source) throws MarshalException
    {
      // Return an empty ByteBuffer for an empty string.
      if (source.isEmpty())
          return ByteBufferUtil.EMPTY_BYTE_BUFFER;

      return ByteBufferUtil.bytes(TimestampSerializer.dateStringToTimestamp(source));
    }

    @Override
    public ByteBuffer fromTimeInMillis(long millis) throws MarshalException
    {
        return ByteBufferUtil.bytes(millis);
    }

    @Override
    public long toTimeInMillis(ByteBuffer value)
    {
        return ByteBufferUtil.toLong(value);
    }

    @Override
    public Term fromJSONObject(Object parsed) throws MarshalException
    {
        if (parsed instanceof Long)
            return new Constants.Value(ByteBufferUtil.bytes((Long) parsed));

        try
        {
            return new Constants.Value(TimestampType.instance.fromString((String) parsed));
        }
        catch (ClassCastException exc)
        {
            throw new MarshalException(String.format(
                    "Expected a long or a datestring representation of a timestamp value, but got a %s: %s",
                    parsed.getClass().getSimpleName(), parsed));
        }
    }

    private String toString(Date date)
    {
        return date != null ? TimestampSerializer.getJsonDateFormatter().format(date) : "";
    }

    @Override
    public String toJSONString(ByteBuffer buffer, ProtocolVersion protocolVersion)
    {
        return '"' + toString(TimestampSerializer.instance.deserialize(buffer)) + '"';
    }

    @Override
    public boolean isCompatibleWith(AbstractType<?> previous)
    {
        if (super.isCompatibleWith(previous))
            return true;

        if (previous instanceof DateType)
        {
            logger.warn("Changing from DateType to TimestampType is allowed, but be wary that they sort differently for pre-unix-epoch timestamps "
                      + "(negative timestamp values) and thus this change will corrupt your data if you have such negative timestamp. So unless you "
                      + "know that you don't have *any* pre-unix-epoch timestamp you should change back to DateType");
            return true;
        }

        return false;
    }

    @Override
    public boolean isValueCompatibleWithInternal(AbstractType<?> otherType)
    {
        return this == otherType || otherType == DateType.instance || otherType == LongType.instance;
    }

    public CQL3Type asCQL3Type()
    {
        return CQL3Type.Native.TIMESTAMP;
    }

    public TypeSerializer<Date> getSerializer()
    {
        return TimestampSerializer.instance;
    }

    @Override
    public int valueLengthIfFixed()
    {
        return 8;
    }

    @Override
    protected void validateDuration(Duration duration)
    {
        if (!duration.hasMillisecondPrecision())
            throw invalidRequest("The duration must have a millisecond precision. Was: %s", duration);
    }

    @Override
    public ByteBuffer getMaskedValue()
    {
        return MASKED_VALUE;
    }
}
