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com.datastax.driver.core.AggregateMetadata Maven / Gradle / Ivy
A driver for Apache Cassandra 1.2+ that works exclusively with the Cassandra Query Language version 3
(CQL3) and Cassandra's binary protocol.
/*
* Copyright DataStax, Inc.
*
* Licensed 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 com.datastax.driver.core;
import com.datastax.driver.core.utils.Bytes;
import com.datastax.driver.core.utils.MoreObjects;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/** Describes a CQL aggregate function (created with {@code CREATE AGGREGATE...}). */
public class AggregateMetadata {
private static final Logger LOGGER = LoggerFactory.getLogger(AggregateMetadata.class);
private final KeyspaceMetadata keyspace;
private final String simpleName;
private final List argumentTypes;
private final String finalFuncSimpleName;
private final String finalFuncFullName;
private final Object initCond;
private final DataType returnType;
private final String stateFuncSimpleName;
private final String stateFuncFullName;
private final DataType stateType;
private final TypeCodec stateTypeCodec;
private AggregateMetadata(
KeyspaceMetadata keyspace,
String simpleName,
List argumentTypes,
String finalFuncSimpleName,
String finalFuncFullName,
Object initCond,
DataType returnType,
String stateFuncSimpleName,
String stateFuncFullName,
DataType stateType,
TypeCodec stateTypeCodec) {
this.keyspace = keyspace;
this.simpleName = simpleName;
this.argumentTypes = argumentTypes;
this.finalFuncSimpleName = finalFuncSimpleName;
this.finalFuncFullName = finalFuncFullName;
this.initCond = initCond;
this.returnType = returnType;
this.stateFuncSimpleName = stateFuncSimpleName;
this.stateFuncFullName = stateFuncFullName;
this.stateType = stateType;
this.stateTypeCodec = stateTypeCodec;
}
// Cassandra < 3.0:
// CREATE TABLE system.schema_aggregates (
// keyspace_name text,
// aggregate_name text,
// signature frozen>,
// argument_types list,
// final_func text,
// initcond blob,
// return_type text,
// state_func text,
// state_type text,
// PRIMARY KEY (keyspace_name, aggregate_name, signature)
// ) WITH CLUSTERING ORDER BY (aggregate_name ASC, signature ASC)
//
// Cassandra >= 3.0:
// CREATE TABLE system.schema_aggregates (
// keyspace_name text,
// aggregate_name text,
// argument_types frozen>,
// final_func text,
// initcond text,
// return_type text,
// state_func text,
// state_type text,
// PRIMARY KEY (keyspace_name, aggregate_name, argument_types)
// ) WITH CLUSTERING ORDER BY (aggregate_name ASC, argument_types ASC)
static AggregateMetadata build(
KeyspaceMetadata ksm, Row row, VersionNumber version, Cluster cluster) {
CodecRegistry codecRegistry = cluster.getConfiguration().getCodecRegistry();
ProtocolVersion protocolVersion =
cluster.getConfiguration().getProtocolOptions().getProtocolVersion();
String simpleName = row.getString("aggregate_name");
List argumentTypes =
parseTypes(ksm, row.getList("argument_types", String.class), version, cluster);
String finalFuncSimpleName = row.getString("final_func");
DataType returnType;
if (version.getMajor() >= 3) {
returnType =
DataTypeCqlNameParser.parse(
row.getString("return_type"),
cluster,
ksm.getName(),
ksm.userTypes,
null,
false,
false);
} else {
returnType =
DataTypeClassNameParser.parseOne(
row.getString("return_type"), protocolVersion, codecRegistry);
}
String stateFuncSimpleName = row.getString("state_func");
String stateTypeName = row.getString("state_type");
DataType stateType;
Object initCond;
if (version.getMajor() >= 3) {
stateType =
DataTypeCqlNameParser.parse(
stateTypeName, cluster, ksm.getName(), ksm.userTypes, null, false, false);
String rawInitCond = row.getString("initcond");
if (rawInitCond == null) {
initCond = null;
} else {
try {
initCond = codecRegistry.codecFor(stateType).parse(rawInitCond);
} catch (RuntimeException e) {
LOGGER.warn(
"Failed to parse INITCOND literal: {}; getInitCond() will return the text literal instead.",
rawInitCond);
initCond = rawInitCond;
}
}
} else {
stateType = DataTypeClassNameParser.parseOne(stateTypeName, protocolVersion, codecRegistry);
ByteBuffer rawInitCond = row.getBytes("initcond");
if (rawInitCond == null) {
initCond = null;
} else {
try {
initCond = codecRegistry.codecFor(stateType).deserialize(rawInitCond, protocolVersion);
} catch (RuntimeException e) {
LOGGER.warn(
"Failed to deserialize INITCOND value: {}; getInitCond() will return the raw bytes instead.",
Bytes.toHexString(rawInitCond));
initCond = rawInitCond;
}
}
}
String finalFuncFullName =
finalFuncSimpleName == null
? null
: Metadata.fullFunctionName(finalFuncSimpleName, Collections.singletonList(stateType));
String stateFuncFullName = makeStateFuncFullName(stateFuncSimpleName, stateType, argumentTypes);
return new AggregateMetadata(
ksm,
simpleName,
argumentTypes,
finalFuncSimpleName,
finalFuncFullName,
initCond,
returnType,
stateFuncSimpleName,
stateFuncFullName,
stateType,
codecRegistry.codecFor(stateType));
}
private static String makeStateFuncFullName(
String stateFuncSimpleName, DataType stateType, List argumentTypes) {
List args = Lists.newArrayList(stateType);
args.addAll(argumentTypes);
return Metadata.fullFunctionName(stateFuncSimpleName, args);
}
private static List parseTypes(
KeyspaceMetadata ksm, List types, VersionNumber version, Cluster cluster) {
if (types.isEmpty()) return Collections.emptyList();
CodecRegistry codecRegistry = cluster.getConfiguration().getCodecRegistry();
ProtocolVersion protocolVersion =
cluster.getConfiguration().getProtocolOptions().getProtocolVersion();
ImmutableList.Builder builder = ImmutableList.builder();
for (String name : types) {
DataType type;
if (version.getMajor() >= 3) {
type =
DataTypeCqlNameParser.parse(
name, cluster, ksm.getName(), ksm.userTypes, null, false, false);
} else {
type = DataTypeClassNameParser.parseOne(name, protocolVersion, codecRegistry);
}
builder.add(type);
}
return builder.build();
}
/**
* Returns a CQL query representing this function in human readable form.
*
* This method is equivalent to {@link #asCQLQuery} but the output is formatted.
*
* @return the CQL query representing this function.
*/
public String exportAsString() {
return asCQLQuery(true);
}
/**
* Returns a CQL query representing this function.
*
*
This method returns a single 'CREATE FUNCTION' query corresponding to this function
* definition.
*
* @return the 'CREATE FUNCTION' query corresponding to this function.
*/
public String asCQLQuery() {
return asCQLQuery(false);
}
@Override
public String toString() {
return asCQLQuery(false);
}
private String asCQLQuery(boolean formatted) {
StringBuilder sb =
new StringBuilder("CREATE AGGREGATE ")
.append(Metadata.quoteIfNecessary(keyspace.getName()))
.append('.');
appendSignature(sb);
TableMetadata.spaceOrNewLine(sb, formatted)
.append("SFUNC ")
.append(Metadata.quoteIfNecessary(stateFuncSimpleName));
TableMetadata.spaceOrNewLine(sb, formatted)
.append("STYPE ")
.append(stateType.asFunctionParameterString());
if (finalFuncSimpleName != null)
TableMetadata.spaceOrNewLine(sb, formatted)
.append("FINALFUNC ")
.append(Metadata.quoteIfNecessary(finalFuncSimpleName));
if (initCond != null)
TableMetadata.spaceOrNewLine(sb, formatted).append("INITCOND ").append(formatInitCond());
sb.append(';');
return sb.toString();
}
private String formatInitCond() {
if (stateTypeCodec.accepts(initCond)) {
try {
return stateTypeCodec.format(initCond);
} catch (RuntimeException e) {
LOGGER.info("Failed to format INITCOND literal: {}", initCond);
}
}
return initCond.toString();
}
private void appendSignature(StringBuilder sb) {
sb.append(Metadata.quoteIfNecessary(simpleName)).append('(');
boolean first = true;
for (DataType type : argumentTypes) {
if (first) first = false;
else sb.append(',');
sb.append(type.asFunctionParameterString());
}
sb.append(')');
}
/**
* Returns the keyspace this aggregate belongs to.
*
* @return the keyspace metadata of the keyspace this aggregate belongs to.
*/
public KeyspaceMetadata getKeyspace() {
return keyspace;
}
/**
* Returns the CQL signature of this aggregate.
*
*
This is the name of the aggregate, followed by the names of the argument types between
* parentheses, like it was specified in the {@code CREATE AGGREGATE...} statement, for example
* {@code sum(int)}.
*
*
Note that the returned signature is not qualified with the keyspace name.
*
* @return the signature of this aggregate.
*/
public String getSignature() {
StringBuilder sb = new StringBuilder();
appendSignature(sb);
return sb.toString();
}
/**
* Returns the simple name of this aggregate.
*
*
This is the name of the aggregate, without arguments. Note that aggregates can be overloaded
* with different argument lists, therefore the simple name may not be unique. For example, {@code
* sum(int)} and {@code sum(int,int)} both have the simple name {@code sum}.
*
* @return the simple name of this aggregate.
* @see #getSignature()
*/
public String getSimpleName() {
return simpleName;
}
/**
* Returns the types of this aggregate's arguments.
*
* @return the types.
*/
public List getArgumentTypes() {
return argumentTypes;
}
/**
* Returns the final function of this aggregate.
*
* This is the function specified with {@code FINALFUNC} in the {@code CREATE AGGREGATE...}
* statement. It transforms the final value after the aggregation is complete.
*
* @return the metadata of the final function, or {@code null} if there is none.
*/
public FunctionMetadata getFinalFunc() {
return (finalFuncFullName == null) ? null : keyspace.functions.get(finalFuncFullName);
}
/**
* Returns the initial state value of this aggregate.
*
*
This is the value specified with {@code INITCOND} in the {@code CREATE AGGREGATE...}
* statement. It's passed to the initial invocation of the state function (if that function does
* not accept null arguments).
*
*
The actual type of the returned object depends on the aggregate's {@link #getStateType()
* state type} and on the {@link TypeCodec codec} used to {@link TypeCodec#parse(String) parse}
* the {@code INITCOND} literal.
*
*
If, for some reason, the {@code INITCOND} literal cannot be parsed, a warning will be logged
* and the returned object will be the original {@code INITCOND} literal in its textual,
* non-parsed form.
*
* @return the initial state, or {@code null} if there is none.
*/
public Object getInitCond() {
return initCond;
}
/**
* Returns the return type of this aggregate.
*
*
This is the final type of the value computed by this aggregate; in other words, the return
* type of the final function if it is defined, or the state type otherwise.
*
* @return the return type.
*/
public DataType getReturnType() {
return returnType;
}
/**
* Returns the state function of this aggregate.
*
*
This is the function specified with {@code SFUNC} in the {@code CREATE AGGREGATE...}
* statement. It aggregates the current state with each row to produce a new state.
*
* @return the metadata of the state function.
*/
public FunctionMetadata getStateFunc() {
return keyspace.functions.get(stateFuncFullName);
}
/**
* Returns the state type of this aggregate.
*
*
This is the type specified with {@code STYPE} in the {@code CREATE AGGREGATE...} statement.
* It defines the type of the value that is accumulated as the aggregate iterates through the
* rows.
*
* @return the state type.
*/
public DataType getStateType() {
return stateType;
}
@Override
public boolean equals(Object other) {
if (other == this) return true;
if (other instanceof AggregateMetadata) {
AggregateMetadata that = (AggregateMetadata) other;
return this.keyspace.getName().equals(that.keyspace.getName())
&& this.argumentTypes.equals(that.argumentTypes)
&& MoreObjects.equal(this.finalFuncFullName, that.finalFuncFullName)
&&
// Note: this might be a problem if a custom codec has been registered for the initCond's
// type, with a target Java type that
// does not properly implement equals. We don't have any control over this, at worst this
// would lead to spurious change
// notifications.
MoreObjects.equal(this.initCond, that.initCond)
&& this.returnType.equals(that.returnType)
&& this.stateFuncFullName.equals(that.stateFuncFullName)
&& this.stateType.equals(that.stateType);
}
return false;
}
@Override
public int hashCode() {
return MoreObjects.hashCode(
this.keyspace.getName(),
this.argumentTypes,
this.finalFuncFullName,
this.initCond,
this.returnType,
this.stateFuncFullName,
this.stateType);
}
}
