src/java/org/apache/cassandra/db/marshal/DoubleType.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 org.apache.cassandra.cql3.CQL3Type;
import org.apache.cassandra.cql3.Constants;
import org.apache.cassandra.cql3.Term;
import org.apache.cassandra.serializers.TypeSerializer;
import org.apache.cassandra.serializers.DoubleSerializer;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.transport.ProtocolVersion;
import org.apache.cassandra.utils.ByteBufferUtil;

public class DoubleType extends AbstractType<Double>
{
    public static final DoubleType instance = new DoubleType();

    DoubleType() {super(ComparisonType.CUSTOM);} // singleton

    public boolean isEmptyValueMeaningless()
    {
        return true;
    }

    public int compareCustom(ByteBuffer o1, ByteBuffer o2)
    {
        if (!o1.hasRemaining() || !o2.hasRemaining())
            return o1.hasRemaining() ? 1 : o2.hasRemaining() ? -1 : 0;

        return compose(o1).compareTo(compose(o2));
    }

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

      Double d;
      try
      {
          d = Double.valueOf(source);
      }
      catch (NumberFormatException e1)
      {
          throw new MarshalException(String.format("Unable to make double from '%s'", source), e1);
      }

      return decompose(d);
    }

    @Override
    public Term fromJSONObject(Object parsed) throws MarshalException
    {
        try
        {
            if (parsed instanceof String)
                return new Constants.Value(fromString((String) parsed));
            else
                return new Constants.Value(getSerializer().serialize(((Number) parsed).doubleValue()));
        }
        catch (ClassCastException exc)
        {
            throw new MarshalException(String.format(
                    "Expected a double value, but got a %s: %s", parsed.getClass().getSimpleName(), parsed));
        }
    }

    @Override
    public String toJSONString(ByteBuffer buffer, ProtocolVersion protocolVersion)
    {
        Double value = getSerializer().deserialize(buffer);
        // JSON does not support NaN, Infinity and -Infinity values. Most of the parser convert them into null.
        if (value.isNaN() || value.isInfinite())
            return "null";
        return value.toString();
    }

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

    public TypeSerializer<Double> getSerializer()
    {
        return DoubleSerializer.instance;
    }

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