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Common functionality for HBase
/*
* 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.hadoop.hbase;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.yetus.audience.InterfaceAudience;
/**
* Extension to {@link Cell} with server side required functions. Server side Cell implementations
* must implement this.
*/
@InterfaceAudience.Private
public interface ExtendedCell extends RawCell, HeapSize {
int CELL_NOT_BASED_ON_CHUNK = -1;
/**
* Write this cell to an OutputStream in a {@link KeyValue} format.
* KeyValue format
* <4 bytes keylength> <4 bytes valuelength> <2 bytes rowlength>
* <row> <1 byte columnfamilylength> <columnfamily> <columnqualifier>
* <8 bytes timestamp> <1 byte keytype> <value> <2 bytes tagslength>
* <tags>
* @param out Stream to which cell has to be written
* @param withTags Whether to write tags.
* @return how many bytes are written. n
*/
// TODO remove the boolean param once HBASE-16706 is done.
default int write(OutputStream out, boolean withTags) throws IOException {
// Key length and then value length
ByteBufferUtils.putInt(out, KeyValueUtil.keyLength(this));
ByteBufferUtils.putInt(out, getValueLength());
// Key
PrivateCellUtil.writeFlatKey(this, out);
if (getValueLength() > 0) {
// Value
out.write(getValueArray(), getValueOffset(), getValueLength());
}
// Tags length and tags byte array
if (withTags && getTagsLength() > 0) {
// Tags length
out.write((byte) (0xff & (getTagsLength() >> 8)));
out.write((byte) (0xff & getTagsLength()));
// Tags byte array
out.write(getTagsArray(), getTagsOffset(), getTagsLength());
}
return getSerializedSize(withTags);
}
/**
* KeyValue format
*
* <4 bytes keylength> <4 bytes valuelength> <2 bytes rowlength>
* <row> <1 byte columnfamilylength> <columnfamily> <columnqualifier>
* <8 bytes timestamp> <1 byte keytype> <value> <2 bytes tagslength>
* <tags>
* @param withTags Whether to write tags.
* @return Bytes count required to serialize this Cell in a {@link KeyValue} format.
*/
// TODO remove the boolean param once HBASE-16706 is done.
default int getSerializedSize(boolean withTags) {
return KeyValueUtil.length(getRowLength(), getFamilyLength(), getQualifierLength(),
getValueLength(), getTagsLength(), withTags);
}
/** Returns Serialized size (defaults to include tag length). */
@Override
default int getSerializedSize() {
return getSerializedSize(true);
}
/**
* Write this Cell into the given buf's offset in a {@link KeyValue} format.
* @param buf The buffer where to write the Cell.
* @param offset The offset within buffer, to write the Cell.
*/
default void write(ByteBuffer buf, int offset) {
KeyValueUtil.appendTo(this, buf, offset, true);
}
/**
* Does a deep copy of the contents to a new memory area and returns it as a new cell.
* @return The deep cloned cell
*/
default ExtendedCell deepClone() {
// When being added to the memstore, deepClone() is called and KeyValue has less heap overhead.
return new KeyValue(this);
}
/**
* Extracts the id of the backing bytebuffer of this cell if it was obtained from fixed sized
* chunks as in case of MemstoreLAB
* @return the chunk id if the cell is backed by fixed sized Chunks, else return
* {@link #CELL_NOT_BASED_ON_CHUNK}; i.e. -1.
*/
default int getChunkId() {
return CELL_NOT_BASED_ON_CHUNK;
}
/**
* Sets with the given seqId.
* @param seqId sequence ID
*/
void setSequenceId(long seqId) throws IOException;
/**
* Sets with the given timestamp.
* @param ts timestamp
*/
void setTimestamp(long ts) throws IOException;
/**
* Sets with the given timestamp.
* @param ts buffer containing the timestamp value
*/
void setTimestamp(byte[] ts) throws IOException;
/**
* A region-specific unique monotonically increasing sequence ID given to each Cell. It always
* exists for cells in the memstore but is not retained forever. It will be kept for
* {@link HConstants#KEEP_SEQID_PERIOD} days, but generally becomes irrelevant after the cell's
* row is no longer involved in any operations that require strict consistency.
* @return seqId (always > 0 if exists), or 0 if it no longer exists
*/
long getSequenceId();
/**
* Contiguous raw bytes representing tags that may start at any index in the containing array.
* @return the tags byte array
*/
byte[] getTagsArray();
/** Returns the first offset where the tags start in the Cell */
int getTagsOffset();
/**
* HBase internally uses 2 bytes to store tags length in Cell. As the tags length is always a
* non-negative number, to make good use of the sign bit, the max of tags length is defined 2 *
* Short.MAX_VALUE + 1 = 65535. As a result, the return type is int, because a short is not
* capable of handling that. Please note that even if the return type is int, the max tags length
* is far less than Integer.MAX_VALUE.
* @return the total length of the tags in the Cell.
*/
int getTagsLength();
/** Returns The byte representation of the KeyValue.TYPE of this cell: one of Put, Delete, etc */
byte getTypeByte();
}