cassandra-trunk/src/java/org/apache/cassandra/db/ClusteringBoundOrBoundary.java
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 *
 * 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
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 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
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 * KIND, either express or implied.  See the License for the
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package org.apache.cassandra.db;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.List;

import org.apache.cassandra.db.marshal.ByteArrayAccessor;
import org.apache.cassandra.db.marshal.ByteBufferAccessor;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.utils.memory.ByteBufferCloner;

/**
 * This class defines a threshold between ranges of clusterings. It can either be a start or end bound of a range, or
 * the boundary between two different defined ranges.
 * <p>
 * The latter is used for range tombstones for 2 main reasons:
 *   1) When merging multiple iterators having range tombstones (that are represented by their start and end markers),
 *      we need to know when a range is close on an iterator, if it is reopened right away. Otherwise, we cannot
 *      easily produce the markers on the merged iterators within risking to fail the sorting guarantees of an
 *      iterator. See this comment for more details: https://goo.gl/yyB5mR.
 *   2) This saves some storage space.
 */
public interface ClusteringBoundOrBoundary<V> extends ClusteringPrefix<V>
{
    public static final ClusteringBoundOrBoundary.Serializer serializer = new Serializer();

    default boolean isBoundary()
    {
        return kind().isBoundary();
    }

    default boolean isOpen(boolean reversed)
    {
        return kind().isOpen(reversed);
    }

    default boolean isClose(boolean reversed)
    {
        return kind().isClose(reversed);
    }

    default ClusteringBoundOrBoundary<ByteBuffer> clone(ByteBufferCloner cloner)
    {
        ByteBuffer[] newValues = new ByteBuffer[size()];
        for (int i = 0; i < size(); i++)
            newValues[i] = cloner.clone(get(i), accessor());
        return ByteBufferAccessor.instance.factory().boundOrBoundary(kind(), newValues);
    }

    default String toString(TableMetadata metadata)
    {
        return toString(metadata.comparator);
    }

    default String toString(ClusteringComparator comparator)
    {
        StringBuilder sb = new StringBuilder();
        sb.append(kind()).append('(');
        for (int i = 0; i < size(); i++)
        {
            if (i > 0)
                sb.append(", ");
            sb.append(comparator.subtype(i).getString(get(i), accessor()));
        }
        return sb.append(')').toString();
    }

    /**
     * Returns the inverse of the current bound.
     * <p>
     * This invert both start into end (and vice-versa) and inclusive into exclusive (and vice-versa).
     *
     * @return the invert of this bound. For instance, if this bound is an exlusive start, this return
     * an inclusive end with the same values.
     */
    public abstract ClusteringBoundOrBoundary<V> invert();

    public static class Serializer
    {
        public <T> void serialize(ClusteringBoundOrBoundary<T> bound, DataOutputPlus out, int version, List<AbstractType<?>> types) throws IOException
        {
            out.writeByte(bound.kind().ordinal());
            out.writeShort(bound.size());
            ClusteringPrefix.serializer.serializeValuesWithoutSize(bound, out, version, types);
        }

        public <T> long serializedSize(ClusteringBoundOrBoundary<T> bound, int version, List<AbstractType<?>> types)
        {
            return 1 // kind ordinal
                 + TypeSizes.sizeof((short)bound.size())
                 + ClusteringPrefix.serializer.valuesWithoutSizeSerializedSize(bound, version, types);
        }

        public ClusteringBoundOrBoundary<byte[]> deserialize(DataInputPlus in, int version, List<AbstractType<?>> types) throws IOException
        {
            Kind kind = Kind.values()[in.readByte()];
            return deserializeValues(in, kind, version, types);
        }

        public void skipValues(DataInputPlus in, Kind kind, int version, List<AbstractType<?>> types) throws IOException
        {
            int size = in.readUnsignedShort();
            if (size == 0)
                return;

            ClusteringPrefix.serializer.skipValuesWithoutSize(in, size, version, types);
        }

        public ClusteringBoundOrBoundary<byte[]> deserializeValues(DataInputPlus in, Kind kind, int version, List<AbstractType<?>> types) throws IOException
        {
            int size = in.readUnsignedShort();
            if (size == 0)
                return ByteArrayAccessor.factory.bound(kind);

            byte[][] values = ClusteringPrefix.serializer.deserializeValuesWithoutSize(in, size, version, types);
            return ByteArrayAccessor.factory.boundOrBoundary(kind, values);
        }
    }
}
