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org.h2.expression.aggregate.JavaAggregate Maven / Gradle / Ivy
/*
* Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression.aggregate;
import java.sql.Connection;
import java.sql.SQLException;
import org.h2.api.Aggregate;
import org.h2.command.Parser;
import org.h2.command.dml.Select;
import org.h2.engine.Session;
import org.h2.engine.UserAggregate;
import org.h2.expression.Expression;
import org.h2.expression.ExpressionVisitor;
import org.h2.message.DbException;
import org.h2.value.DataType;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
import org.h2.value.ValueBoolean;
import org.h2.value.ValueNull;
import org.h2.value.ValueRow;
/**
* This class wraps a user-defined aggregate.
*/
public class JavaAggregate extends AbstractAggregate {
private final UserAggregate userAggregate;
private int[] argTypes;
private int dataType;
private Connection userConnection;
public JavaAggregate(UserAggregate userAggregate, Expression[] args, Select select, boolean distinct) {
super(select, args, distinct);
this.userAggregate = userAggregate;
}
@Override
public int getCost() {
int cost = 5;
for (Expression e : args) {
cost += e.getCost();
}
if (filterCondition != null) {
cost += filterCondition.getCost();
}
return cost;
}
@Override
public StringBuilder getSQL(StringBuilder builder, boolean alwaysQuote) {
Parser.quoteIdentifier(builder, userAggregate.getName(), alwaysQuote).append('(');
writeExpressions(builder, args, alwaysQuote);
builder.append(')');
return appendTailConditions(builder, alwaysQuote);
}
@Override
public boolean isEverything(ExpressionVisitor visitor) {
if (!super.isEverything(visitor)) {
return false;
}
switch (visitor.getType()) {
case ExpressionVisitor.DETERMINISTIC:
// TODO optimization: some functions are deterministic, but we don't
// know (no setting for that)
case ExpressionVisitor.OPTIMIZABLE_AGGREGATE:
// user defined aggregate functions can not be optimized
return false;
case ExpressionVisitor.GET_DEPENDENCIES:
visitor.addDependency(userAggregate);
break;
default:
}
for (Expression e : args) {
if (e != null && !e.isEverything(visitor)) {
return false;
}
}
return filterCondition == null || filterCondition.isEverything(visitor);
}
@Override
public Expression optimize(Session session) {
super.optimize(session);
userConnection = session.createConnection(false);
int len = args.length;
argTypes = new int[len];
for (int i = 0; i < len; i++) {
int type = args[i].getType().getValueType();
argTypes[i] = type;
}
try {
Aggregate aggregate = getInstance();
dataType = aggregate.getInternalType(argTypes);
type = TypeInfo.getTypeInfo(dataType);
} catch (SQLException e) {
throw DbException.convert(e);
}
return this;
}
private Aggregate getInstance() {
Aggregate agg = userAggregate.getInstance();
try {
agg.init(userConnection);
} catch (SQLException ex) {
throw DbException.convert(ex);
}
return agg;
}
@Override
public Value getAggregatedValue(Session session, Object aggregateData) {
try {
Aggregate agg;
if (distinct) {
agg = getInstance();
AggregateDataCollecting data = (AggregateDataCollecting) aggregateData;
if (data != null) {
for (Value value : data.values) {
if (args.length == 1) {
agg.add(value.getObject());
} else {
Value[] values = ((ValueRow) value).getList();
Object[] argValues = new Object[args.length];
for (int i = 0, len = args.length; i < len; i++) {
argValues[i] = values[i].getObject();
}
agg.add(argValues);
}
}
}
} else {
agg = (Aggregate) aggregateData;
if (agg == null) {
agg = getInstance();
}
}
Object obj = agg.getResult();
if (obj == null) {
return ValueNull.INSTANCE;
}
return DataType.convertToValue(session, obj, dataType);
} catch (SQLException e) {
throw DbException.convert(e);
}
}
@Override
protected void updateAggregate(Session session, Object aggregateData) {
updateData(session, aggregateData, null);
}
private void updateData(Session session, Object aggregateData, Value[] remembered) {
try {
if (distinct) {
AggregateDataCollecting data = (AggregateDataCollecting) aggregateData;
Value[] argValues = new Value[args.length];
Value arg = null;
for (int i = 0, len = args.length; i < len; i++) {
arg = remembered == null ? args[i].getValue(session) : remembered[i];
arg = arg.convertTo(argTypes[i], session, false);
argValues[i] = arg;
}
data.add(session.getDatabase(), args.length == 1 ? arg : ValueRow.get(argValues));
} else {
Aggregate agg = (Aggregate) aggregateData;
Object[] argValues = new Object[args.length];
Object arg = null;
for (int i = 0, len = args.length; i < len; i++) {
Value v = remembered == null ? args[i].getValue(session) : remembered[i];
v = v.convertTo(argTypes[i], session, false);
arg = v.getObject();
argValues[i] = arg;
}
agg.add(args.length == 1 ? arg : argValues);
}
} catch (SQLException e) {
throw DbException.convert(e);
}
}
@Override
protected void updateGroupAggregates(Session session, int stage) {
super.updateGroupAggregates(session, stage);
for (Expression expr : args) {
expr.updateAggregate(session, stage);
}
}
@Override
protected int getNumExpressions() {
int n = args.length;
if (filterCondition != null) {
n++;
}
return n;
}
@Override
protected void rememberExpressions(Session session, Value[] array) {
int length = args.length;
for (int i = 0; i < length; i++) {
array[i] = args[i].getValue(session);
}
if (filterCondition != null) {
array[length] = ValueBoolean.get(filterCondition.getBooleanValue(session));
}
}
@Override
protected void updateFromExpressions(Session session, Object aggregateData, Value[] array) {
if (filterCondition == null || array[getNumExpressions() - 1].getBoolean()) {
updateData(session, aggregateData, array);
}
}
@Override
protected Object createAggregateData() {
return distinct ? new AggregateDataCollecting(true) : getInstance();
}
}
