/*
* Copyright (C) 2010-2012 The Async HBase Authors. All rights reserved.
* This file is part of Async HBase.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the StumbleUpon nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
package org.hbase.async;
import java.util.ArrayList;
import org.jboss.netty.buffer.ChannelBuffer;
import org.hbase.async.generated.ClientPB;
/**
* Reads something from HBase.
*
* <h1>A note on passing {@code byte} arrays in argument</h1>
* None of the method that receive a {@code byte[]} in argument will copy it.
* For more info, please refer to the documentation of {@link HBaseRpc}.
* <h1>A note on passing {@code String}s in argument</h1>
* All strings are assumed to use the platform's default charset.
*/
public final class GetRequest extends HBaseRpc
implements HBaseRpc.HasTable, HBaseRpc.HasKey,
HBaseRpc.HasFamily, HBaseRpc.HasQualifiers {
private static final byte[] GET = new byte[] { 'g', 'e', 't' };
static final byte[] GGET = new byte[] { 'G', 'e', 't' }; // HBase 0.95+
private static final byte[] EXISTS =
new byte[] { 'e', 'x', 'i', 's', 't', 's' };
private byte[] family; // TODO(tsuna): Handle multiple families?
private byte[][] qualifiers;
private long lockid = RowLock.NO_LOCK;
/**
* How many versions of each cell to retrieve.
* The least significant bit is used as a flag to indicate when
* this Get request is in fact an Exist request (i.e. like Get
* except that instead of returning a result the RPC returns a
* boolean indicating whether the row exists or not).
*/
private int versions = 1 << 1;
/** When set in the `versions' field, this is an Exist RPC. */
private static final int EXIST_FLAG = 0x1;
/**
* Constructor.
* <strong>These byte arrays will NOT be copied.</strong>
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
*/
public GetRequest(final byte[] table, final byte[] key) {
super(table, key);
}
/**
* Constructor.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* <strong>This byte array will NOT be copied.</strong>
*/
public GetRequest(final String table, final byte[] key) {
this(table.getBytes(), key);
}
/**
* Constructor.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
*/
public GetRequest(final String table, final String key) {
this(table.getBytes(), key.getBytes());
}
/**
* Constructor.
* <strong>These byte arrays will NOT be copied.</strong>
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @param family The column family.
* @since 1.5
*/
public GetRequest(final byte[] table,
final byte[] key,
final byte[] family) {
super(table, key);
this.family(family);
}
/**
* Constructor.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @param family The column family.
* @since 1.5
*/
public GetRequest(final String table,
final String key,
final String family) {
this(table, key);
this.family(family);
}
/**
* Constructor.
* <strong>These byte arrays will NOT be copied.</strong>
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @param family The column family.
* @param qualifier The column qualifier.
* @since 1.5
*/
public GetRequest(final byte[] table,
final byte[] key,
final byte[] family,
final byte[] qualifier) {
super(table, key);
this.family(family);
this.qualifier(qualifier);
}
/**
* Constructor.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @param family The column family.
* @param qualifier The column qualifier.
* @since 1.5
*/
public GetRequest(final String table,
final String key,
final String family,
final String qualifier) {
this(table, key);
this.family(family);
this.qualifier(qualifier);
}
/**
* Private constructor to build an "exists" RPC.
* @param unused Unused, simply used to help the compiler find this ctor.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
*/
private GetRequest(final float unused,
final byte[] table,
final byte[] key) {
super(table, key);
this.versions |= EXIST_FLAG;
}
/**
* Package-private factory method to build an "exists" RPC.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @return An {@link HBaseRpc} that will return a {@link Boolean}
* indicating whether or not the given table / key exists.
*/
static HBaseRpc exists(final byte[] table, final byte[] key) {
return new GetRequest(0F, table, key);
}
/**
* Package-private factory method to build an "exists" RPC.
* @param table The non-empty name of the table to use.
* @param key The row key to get in that table.
* @param family The column family to get in the table.
* @return An {@link HBaseRpc} that will return a {@link Boolean}
* indicating whether or not the given table / key exists.
*/
static HBaseRpc exists(final byte[] table,
final byte[] key, final byte[] family) {
final GetRequest rpc = new GetRequest(0F, table, key);
rpc.family(family);
return rpc;
}
/** Returns true if this is actually an "Get" RPC. */
private boolean isGetRequest() {
return (versions & EXIST_FLAG) == 0;
}
/**
* Specifies a particular column family to get.
* @param family The column family.
* <strong>This byte array will NOT be copied.</strong>
* @return {@code this}, always.
*/
public GetRequest family(final byte[] family) {
KeyValue.checkFamily(family);
this.family = family;
return this;
}
/** Specifies a particular column family to get. */
public GetRequest family(final String family) {
return family(family.getBytes());
}
/**
* Specifies a particular column qualifier to get.
* @param qualifier The column qualifier.
* <strong>This byte array will NOT be copied.</strong>
* @return {@code this}, always.
*/
public GetRequest qualifier(final byte[] qualifier) {
if (qualifier == null) {
throw new NullPointerException("qualifier");
}
KeyValue.checkQualifier(qualifier);
this.qualifiers = new byte[][] { qualifier };
return this;
}
/**
* Specifies a particular set of column qualifiers to get.
* @param qualifiers The column qualifiers.
* <strong>This byte array will NOT be copied.</strong>
* @return {@code this}, always.
* @since 1.1
*/
public GetRequest qualifiers(final byte[][] qualifiers) {
if (qualifiers == null) {
throw new NullPointerException("qualifiers");
}
for (final byte[] qualifier : qualifiers) {
KeyValue.checkQualifier(qualifier);
}
this.qualifiers = qualifiers;
return this;
}
/** Specifies a particular column qualifier to get. */
public GetRequest qualifier(final String qualifier) {
return qualifier(qualifier.getBytes());
}
/** Specifies an explicit row lock to use with this request. */
public GetRequest withRowLock(final RowLock lock) {
lockid = lock.id();
return this;
}
/**
* Sets the maximum number of versions to return for each cell read.
* <p>
* By default only the most recent version of each cell is read.
* If you want to get all possible versions available, pass
* {@link Integer#MAX_VALUE} in argument.
* @param versions A strictly positive number of versions to return.
* @return {@code this}, always.
* @since 1.4
* @throws IllegalArgumentException if {@code versions <= 0}
*/
public GetRequest maxVersions(final int versions) {
if (versions <= 0) {
throw new IllegalArgumentException("Need a strictly positive number: "
+ versions);
}
this.versions = (versions << 1) | (this.versions & EXIST_FLAG);
return this;
}
/**
* Returns the maximum number of versions to return for each cell scanned.
* @return A strictly positive integer.
* @since 1.4
*/
public int maxVersions() {
return versions >>> 1;
}
@Override
byte[] method(final byte server_version) {
if (server_version >= RegionClient.SERVER_VERSION_095_OR_ABOVE) {
return GGET;
}
return isGetRequest() ? GET : EXISTS;
}
@Override
public byte[] table() {
return table;
}
@Override
public byte[] key() {
return key;
}
@Override
public byte[] family() {
return family;
}
@Override
public byte[][] qualifiers() {
return qualifiers;
}
public String toString() {
final String klass = isGetRequest() ? "GetRequest" : "Exists";
return super.toStringWithQualifiers(klass, family, qualifiers);
}
// ---------------------- //
// Package private stuff. //
// ---------------------- //
/**
* Predicts a lower bound on the serialized size of this RPC.
* This is to avoid using a dynamic buffer, to avoid re-sizing the buffer.
* Since we use a static buffer, if the prediction is wrong and turns out
* to be less than what we need, there will be an exception which will
* prevent the RPC from being serialized. That'd be a severe bug.
*/
private int predictSerializedSize(final byte server_version) {
int size = 0;
size += 4; // int: Number of parameters.
size += 1; // byte: Type of the 1st parameter.
size += 3; // vint: region name length (3 bytes => max length = 32768).
size += region.name().length; // The region name.
size += 1; // byte: Type of the 2nd parameter.
size += 1; // byte: Type again (see HBASE-2877).
size += 1; // byte: Version of Get.
size += 3; // vint: row key length (3 bytes => max length = 32768).
size += key.length; // The row key.
size += 8; // long: Lock ID.
size += 4; // int: Max number of versions to return.
size += 1; // byte: Whether or not to use a filter.
if (server_version >= 26) { // New in 0.90 (because of HBASE-3174).
size += 1; // byte: Whether or not to cache the blocks read.
}
size += 8; // long: Minimum timestamp.
size += 8; // long: Maximum timestamp.
size += 1; // byte: Boolean: "all time".
size += 4; // int: Number of families.
if (family != null) {
size += 1; // vint: Family length (guaranteed on 1 byte).
size += family.length; // The family.
size += 1; // byte: Boolean: do we want specific qualifiers?
if (qualifiers != null) {
size += 4; // int: How many qualifiers follow?
for (final byte[] qualifier : qualifiers) {
size += 3; // vint: Qualifier length.
size += qualifier.length; // The qualifier.
}
}
}
if (server_version >= RegionClient.SERVER_VERSION_092_OR_ABOVE) {
size += 4; // int: Attributes map. Always 0.
}
return size;
}
/** Serializes this request. */
ChannelBuffer serialize(final byte server_version) {
if (server_version < RegionClient.SERVER_VERSION_095_OR_ABOVE) {
return serializeOld(server_version);
}
final ClientPB.Get.Builder getpb = ClientPB.Get.newBuilder()
.setRow(Bytes.wrap(key));
if (family != null) {
final ClientPB.Column.Builder column = ClientPB.Column.newBuilder();
column.setFamily(Bytes.wrap(family));
if (qualifiers != null) {
for (final byte[] qualifier : qualifiers) {
column.addQualifier(Bytes.wrap(qualifier));
}
}
getpb.addColumn(column.build());
}
// TODO: Filters.
final int versions = maxVersions(); // Shadows this.versions
if (versions != 1) {
getpb.setMaxVersions(versions);
}
if (!isGetRequest()) {
getpb.setExistenceOnly(true);
}
final ClientPB.GetRequest.Builder get = ClientPB.GetRequest.newBuilder()
.setRegion(region.toProtobuf())
.setGet(getpb.build());
return toChannelBuffer(GetRequest.GGET, get.build());
}
/** Serializes this request for HBase 0.94 and before. */
private ChannelBuffer serializeOld(final byte server_version) {
final ChannelBuffer buf = newBuffer(server_version,
predictSerializedSize(server_version));
buf.writeInt(2); // Number of parameters.
// 1st param: byte array containing region name
writeHBaseByteArray(buf, region.name());
// 2nd param: Get object
buf.writeByte(32); // Code for a `Get' parameter.
buf.writeByte(32); // Code again (see HBASE-2877).
buf.writeByte(1); // Get#GET_VERSION. Undocumented versioning of Get.
writeByteArray(buf, key);
buf.writeLong(lockid); // Lock ID.
buf.writeInt(maxVersions()); // Max number of versions to return.
buf.writeByte(0x00); // boolean (false): whether or not to use a filter.
// If the previous boolean was true:
// writeByteArray(buf, filter name as byte array);
// write the filter itself
if (server_version >= 26) { // New in 0.90 (because of HBASE-3174).
buf.writeByte(0x01); // boolean (true): whether to cache the blocks.
}
// TimeRange
buf.writeLong(0); // Minimum timestamp.
buf.writeLong(Long.MAX_VALUE); // Maximum timestamp.
buf.writeByte(0x01); // Boolean: "all time".
// The "all time" boolean indicates whether or not this time range covers
// all possible times. Not sure why it's part of the serialized RPC...
// Families.
buf.writeInt(family != null ? 1 : 0); // Number of families that follow.
if (family != null) {
// Each family is then written like so:
writeByteArray(buf, family); // Column family name.
if (qualifiers != null) {
buf.writeByte(0x01); // Boolean: We want specific qualifiers.
buf.writeInt(qualifiers.length); // How many qualifiers do we want?
for (final byte[] qualifier : qualifiers) {
writeByteArray(buf, qualifier); // Column qualifier name.
}
} else {
buf.writeByte(0x00); // Boolean: we don't want specific qualifiers.
}
}
if (server_version >= RegionClient.SERVER_VERSION_092_OR_ABOVE) {
buf.writeInt(0); // Attributes map: number of elements.
}
return buf;
}
@Override
Object deserialize(final ChannelBuffer buf, final int cell_size) {
final ClientPB.GetResponse resp =
readProtobuf(buf, ClientPB.GetResponse.PARSER);
if (isGetRequest()) {
return extractResponse(resp, buf, cell_size);
} else {
final ClientPB.Result result = resp.getResult();
return result != null ? result.getExists() : false; // is `null' possible here?
}
}
/**
* Transforms a protobuf get response into a list of {@link KeyValue}.
* @param resp The protobuf response from which to extract the KVs.
* @param buf The buffer from which the protobuf was read.
* @param cell_size The number of bytes of the cell block that follows,
* in the buffer.
*/
static ArrayList<KeyValue> extractResponse(final ClientPB.GetResponse resp,
final ChannelBuffer buf,
final int cell_size) {
final ClientPB.Result res = resp.getResult();
if (res == null) {
return new ArrayList<KeyValue>(0);
}
return convertResult(res, buf, cell_size);
}
/**
* Converts a protobuf result into a list of {@link KeyValue}.
* @param res The protobuf'ed results from which to extract the KVs.
* @param buf The buffer from which the protobuf was read.
* @param cell_size The number of bytes of the cell block that follows,
* in the buffer.
*/
static ArrayList<KeyValue> convertResult(final ClientPB.Result res,
final ChannelBuffer buf,
final int cell_size) {
final int cell_kvs = RegionClient.numberOfKeyValuesAhead(buf, cell_size);
final int size = res.getCellCount();
final ArrayList<KeyValue> rows = new ArrayList<KeyValue>(size + cell_kvs);
KeyValue kv = null;
for (int i = 0; i < size; i++) {
kv = KeyValue.fromCell(res.getCell(i), kv);
rows.add(kv);
}
for (int i = 0; i < cell_kvs; i++) {
final int kv_length = buf.readInt();
kv = KeyValue.fromBuffer(buf, kv);
rows.add(kv);
}
return rows;
}
}