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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cql3;
import java.nio.ByteBuffer;
import java.util.*;
import io.netty.buffer.ByteBuf;
import org.apache.cassandra.transport.*;
import org.apache.cassandra.db.marshal.AbstractType;
import org.apache.cassandra.db.marshal.LongType;
import org.apache.cassandra.db.marshal.ReversedType;
import org.apache.cassandra.thrift.Column;
import org.apache.cassandra.thrift.CqlMetadata;
import org.apache.cassandra.thrift.CqlResult;
import org.apache.cassandra.thrift.CqlResultType;
import org.apache.cassandra.thrift.CqlRow;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.service.pager.PagingState;
public class ResultSet
{
public static final Codec codec = new Codec();
public static final ColumnIdentifier COUNT_COLUMN = new ColumnIdentifier("count", false);
public final Metadata metadata;
public final List> rows;
public ResultSet(List metadata)
{
this(new Metadata(metadata), new ArrayList>());
}
public ResultSet(Metadata metadata, List> rows)
{
this.metadata = metadata;
this.rows = rows;
}
public int size()
{
return rows.size();
}
public void addRow(List row)
{
assert row.size() == metadata.valueCount();
rows.add(row);
}
public void addColumnValue(ByteBuffer value)
{
if (rows.isEmpty() || lastRow().size() == metadata.valueCount())
rows.add(new ArrayList(metadata.valueCount()));
lastRow().add(value);
}
private List lastRow()
{
return rows.get(rows.size() - 1);
}
public void reverse()
{
Collections.reverse(rows);
}
public void trim(int limit)
{
int toRemove = rows.size() - limit;
if (toRemove > 0)
{
for (int i = 0; i < toRemove; i++)
rows.remove(rows.size() - 1);
}
}
public ResultSet makeCountResult(ColumnIdentifier alias)
{
assert metadata.names != null;
String ksName = metadata.names.get(0).ksName;
String cfName = metadata.names.get(0).cfName;
long count = rows.size();
return makeCountResult(ksName, cfName, count, alias);
}
public static ResultSet.Metadata makeCountMetadata(String ksName, String cfName, ColumnIdentifier alias)
{
ColumnSpecification spec = new ColumnSpecification(ksName, cfName, alias == null ? COUNT_COLUMN : alias, LongType.instance);
return new Metadata(Collections.singletonList(spec));
}
public static ResultSet makeCountResult(String ksName, String cfName, long count, ColumnIdentifier alias)
{
List> newRows = Collections.singletonList(Collections.singletonList(ByteBufferUtil.bytes(count)));
return new ResultSet(makeCountMetadata(ksName, cfName, alias), newRows);
}
public CqlResult toThriftResult()
{
assert metadata.names != null;
String UTF8 = "UTF8Type";
CqlMetadata schema = new CqlMetadata(new HashMap(),
new HashMap(),
// The 2 following ones shouldn't be needed in CQL3
UTF8, UTF8);
for (int i = 0; i < metadata.columnCount; i++)
{
ColumnSpecification spec = metadata.names.get(i);
ByteBuffer colName = ByteBufferUtil.bytes(spec.name.toString());
schema.name_types.put(colName, UTF8);
AbstractType normalizedType = spec.type instanceof ReversedType ? ((ReversedType)spec.type).baseType : spec.type;
schema.value_types.put(colName, normalizedType.toString());
}
List cqlRows = new ArrayList(rows.size());
for (List row : rows)
{
List thriftCols = new ArrayList(metadata.columnCount);
for (int i = 0; i < metadata.columnCount; i++)
{
Column col = new Column(ByteBufferUtil.bytes(metadata.names.get(i).name.toString()));
col.setValue(row.get(i));
thriftCols.add(col);
}
// The key of CqlRow shoudn't be needed in CQL3
cqlRows.add(new CqlRow(ByteBufferUtil.EMPTY_BYTE_BUFFER, thriftCols));
}
CqlResult res = new CqlResult(CqlResultType.ROWS);
res.setRows(cqlRows).setSchema(schema);
return res;
}
@Override
public String toString()
{
try
{
StringBuilder sb = new StringBuilder();
sb.append(metadata).append('\n');
for (List row : rows)
{
for (int i = 0; i < row.size(); i++)
{
ByteBuffer v = row.get(i);
if (v == null)
{
sb.append(" | null");
}
else
{
sb.append(" | ");
if (metadata.flags.contains(Flag.NO_METADATA))
sb.append("0x").append(ByteBufferUtil.bytesToHex(v));
else
sb.append(metadata.names.get(i).type.getString(v));
}
}
sb.append('\n');
}
sb.append("---");
return sb.toString();
}
catch (Exception e)
{
throw new RuntimeException(e);
}
}
public static class Codec implements CBCodec
{
/*
* Format:
* - metadata
* - rows count (4 bytes)
* - rows
*/
public ResultSet decode(ByteBuf body, int version)
{
Metadata m = Metadata.codec.decode(body, version);
int rowCount = body.readInt();
ResultSet rs = new ResultSet(m, new ArrayList>(rowCount));
// rows
int totalValues = rowCount * m.columnCount;
for (int i = 0; i < totalValues; i++)
rs.addColumnValue(CBUtil.readValue(body));
return rs;
}
public void encode(ResultSet rs, ByteBuf dest, int version)
{
Metadata.codec.encode(rs.metadata, dest, version);
dest.writeInt(rs.rows.size());
for (List row : rs.rows)
{
// Note that we do only want to serialize only the first columnCount values, even if the row
// as more: see comment on Metadata.names field.
for (int i = 0; i < rs.metadata.columnCount; i++)
CBUtil.writeValue(row.get(i), dest);
}
}
public int encodedSize(ResultSet rs, int version)
{
int size = Metadata.codec.encodedSize(rs.metadata, version) + 4;
for (List row : rs.rows)
{
for (int i = 0; i < rs.metadata.columnCount; i++)
size += CBUtil.sizeOfValue(row.get(i));
}
return size;
}
}
public static class Metadata
{
public static final CBCodec codec = new Codec();
public static final Metadata EMPTY = new Metadata(EnumSet.of(Flag.NO_METADATA), null, 0, null);
private final EnumSet flags;
// Please note that columnCount can actually be smaller than names, even if names is not null. This is
// used to include columns in the resultSet that we need to do post-query re-orderings
// (SelectStatement.orderResults) but that shouldn't be sent to the user as they haven't been requested
// (CASSANDRA-4911). So the serialization code will exclude any columns in name whose index is >= columnCount.
public final List names;
private final int columnCount;
private PagingState pagingState;
public Metadata(List names)
{
this(EnumSet.noneOf(Flag.class), names, names.size(), null);
if (!names.isEmpty() && allInSameCF())
flags.add(Flag.GLOBAL_TABLES_SPEC);
}
private Metadata(EnumSet flags, List names, int columnCount, PagingState pagingState)
{
this.flags = flags;
this.names = names;
this.columnCount = columnCount;
this.pagingState = pagingState;
}
public Metadata copy()
{
return new Metadata(EnumSet.copyOf(flags), names, columnCount, pagingState);
}
/**
* Return only the column names requested by the user, excluding those added for post-query re-orderings,
* see definition of names and columnCount.
**/
public List requestNames()
{
return names.subList(0, columnCount);
}
// The maximum number of values that the ResultSet can hold. This can be bigger than columnCount due to CASSANDRA-4911
public int valueCount()
{
return names == null ? columnCount : names.size();
}
/**
* Adds the specified column which will not be serialized.
*
* @param name the column
*/
public void addNonSerializedColumn(ColumnSpecification name)
{
// See comment above. Because columnCount doesn't account the newly added name, it
// won't be serialized.
names.add(name);
}
private boolean allInSameCF()
{
if (names == null)
return false;
assert !names.isEmpty();
Iterator iter = names.iterator();
ColumnSpecification first = iter.next();
while (iter.hasNext())
{
ColumnSpecification name = iter.next();
if (!name.ksName.equals(first.ksName) || !name.cfName.equals(first.cfName))
return false;
}
return true;
}
public void setHasMorePages(PagingState pagingState)
{
this.pagingState = pagingState;
if (pagingState == null)
flags.remove(Flag.HAS_MORE_PAGES);
else
flags.add(Flag.HAS_MORE_PAGES);
}
public void setSkipMetadata()
{
flags.add(Flag.NO_METADATA);
}
@Override
public String toString()
{
StringBuilder sb = new StringBuilder();
if (names == null)
{
sb.append("[").append(columnCount).append(" columns]");
}
else
{
for (ColumnSpecification name : names)
{
sb.append("[").append(name.name.toString());
sb.append("(").append(name.ksName).append(", ").append(name.cfName).append(")");
sb.append(", ").append(name.type).append("]");
}
}
if (flags.contains(Flag.HAS_MORE_PAGES))
sb.append(" (to be continued)");
return sb.toString();
}
private static class Codec implements CBCodec
{
public Metadata decode(ByteBuf body, int version)
{
// flags & column count
int iflags = body.readInt();
int columnCount = body.readInt();
EnumSet flags = Flag.deserialize(iflags);
PagingState state = null;
if (flags.contains(Flag.HAS_MORE_PAGES))
state = PagingState.deserialize(CBUtil.readValue(body));
if (flags.contains(Flag.NO_METADATA))
return new Metadata(flags, null, columnCount, state);
boolean globalTablesSpec = flags.contains(Flag.GLOBAL_TABLES_SPEC);
String globalKsName = null;
String globalCfName = null;
if (globalTablesSpec)
{
globalKsName = CBUtil.readString(body);
globalCfName = CBUtil.readString(body);
}
// metadata (names/types)
List names = new ArrayList(columnCount);
for (int i = 0; i < columnCount; i++)
{
String ksName = globalTablesSpec ? globalKsName : CBUtil.readString(body);
String cfName = globalTablesSpec ? globalCfName : CBUtil.readString(body);
ColumnIdentifier colName = new ColumnIdentifier(CBUtil.readString(body), true);
AbstractType type = DataType.toType(DataType.codec.decodeOne(body, version));
names.add(new ColumnSpecification(ksName, cfName, colName, type));
}
return new Metadata(flags, names, names.size(), state);
}
public void encode(Metadata m, ByteBuf dest, int version)
{
boolean noMetadata = m.flags.contains(Flag.NO_METADATA);
boolean globalTablesSpec = m.flags.contains(Flag.GLOBAL_TABLES_SPEC);
boolean hasMorePages = m.flags.contains(Flag.HAS_MORE_PAGES);
assert version > 1 || (!m.flags.contains(Flag.HAS_MORE_PAGES) && !noMetadata): "version = " + version + ", flags = " + m.flags;
dest.writeInt(Flag.serialize(m.flags));
dest.writeInt(m.columnCount);
if (hasMorePages)
CBUtil.writeValue(m.pagingState.serialize(), dest);
if (!noMetadata)
{
if (globalTablesSpec)
{
CBUtil.writeString(m.names.get(0).ksName, dest);
CBUtil.writeString(m.names.get(0).cfName, dest);
}
for (int i = 0; i < m.columnCount; i++)
{
ColumnSpecification name = m.names.get(i);
if (!globalTablesSpec)
{
CBUtil.writeString(name.ksName, dest);
CBUtil.writeString(name.cfName, dest);
}
CBUtil.writeString(name.name.toString(), dest);
DataType.codec.writeOne(DataType.fromType(name.type, version), dest, version);
}
}
}
public int encodedSize(Metadata m, int version)
{
boolean noMetadata = m.flags.contains(Flag.NO_METADATA);
boolean globalTablesSpec = m.flags.contains(Flag.GLOBAL_TABLES_SPEC);
boolean hasMorePages = m.flags.contains(Flag.HAS_MORE_PAGES);
int size = 8;
if (hasMorePages)
size += CBUtil.sizeOfValue(m.pagingState.serialize());
if (!noMetadata)
{
if (globalTablesSpec)
{
size += CBUtil.sizeOfString(m.names.get(0).ksName);
size += CBUtil.sizeOfString(m.names.get(0).cfName);
}
for (int i = 0; i < m.columnCount; i++)
{
ColumnSpecification name = m.names.get(i);
if (!globalTablesSpec)
{
size += CBUtil.sizeOfString(name.ksName);
size += CBUtil.sizeOfString(name.cfName);
}
size += CBUtil.sizeOfString(name.name.toString());
size += DataType.codec.oneSerializedSize(DataType.fromType(name.type, version), version);
}
}
return size;
}
}
}
public static enum Flag
{
// The order of that enum matters!!
GLOBAL_TABLES_SPEC,
HAS_MORE_PAGES,
NO_METADATA;
public static EnumSet deserialize(int flags)
{
EnumSet set = EnumSet.noneOf(Flag.class);
Flag[] values = Flag.values();
for (int n = 0; n < values.length; n++)
{
if ((flags & (1 << n)) != 0)
set.add(values[n]);
}
return set;
}
public static int serialize(EnumSet flags)
{
int i = 0;
for (Flag flag : flags)
i |= 1 << flag.ordinal();
return i;
}
}
}