/*
* 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.facebook.presto.connector.system;
import com.facebook.presto.spi.ColumnHandle;
import com.facebook.presto.spi.ColumnMetadata;
import com.facebook.presto.spi.ConnectorPageSource;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.ConnectorSplit;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.RecordCursor;
import com.facebook.presto.spi.RecordPageSource;
import com.facebook.presto.spi.RecordSet;
import com.facebook.presto.spi.SchemaTableName;
import com.facebook.presto.spi.SystemTable;
import com.facebook.presto.spi.connector.ConnectorPageSourceProvider;
import com.facebook.presto.spi.connector.ConnectorTransactionHandle;
import com.facebook.presto.spi.predicate.Domain;
import com.facebook.presto.spi.predicate.TupleDomain;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.split.MappedPageSource;
import com.facebook.presto.split.MappedRecordSet;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import static com.facebook.presto.spi.StandardErrorCode.GENERIC_INTERNAL_ERROR;
import static com.facebook.presto.spi.predicate.TupleDomain.withColumnDomains;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.Maps.uniqueIndex;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
public class SystemPageSourceProvider
implements ConnectorPageSourceProvider
{
private final Map<SchemaTableName, SystemTable> tables;
public SystemPageSourceProvider(Set<SystemTable> tables)
{
this.tables = uniqueIndex(tables, table -> table.getTableMetadata().getTable());
}
@Override
public ConnectorPageSource createPageSource(ConnectorTransactionHandle transactionHandle, ConnectorSession session, ConnectorSplit split, List<ColumnHandle> columns)
{
requireNonNull(columns, "columns is null");
SystemTransactionHandle systemTransaction = (SystemTransactionHandle) transactionHandle;
SystemSplit systemSplit = (SystemSplit) split;
SchemaTableName tableName = systemSplit.getTableHandle().getSchemaTableName();
SystemTable systemTable = tables.get(tableName);
checkArgument(systemTable != null, "Table %s does not exist", tableName);
List<ColumnMetadata> tableColumns = systemTable.getTableMetadata().getColumns();
Map<String, Integer> columnsByName = new HashMap<>();
for (int i = 0; i < tableColumns.size(); i++) {
ColumnMetadata column = tableColumns.get(i);
if (columnsByName.put(column.getName(), i) != null) {
throw new PrestoException(GENERIC_INTERNAL_ERROR, "Duplicate column name: " + column.getName());
}
}
ImmutableList.Builder<Integer> userToSystemFieldIndex = ImmutableList.builder();
for (ColumnHandle column : columns) {
String columnName = ((SystemColumnHandle) column).getColumnName();
Integer index = columnsByName.get(columnName);
if (index == null) {
throw new PrestoException(GENERIC_INTERNAL_ERROR, format("Column does not exist: %s.%s", tableName, columnName));
}
userToSystemFieldIndex.add(index);
}
TupleDomain<ColumnHandle> constraint = systemSplit.getConstraint();
ImmutableMap.Builder<Integer, Domain> newConstraints = ImmutableMap.builder();
for (Map.Entry<ColumnHandle, Domain> entry : constraint.getDomains().get().entrySet()) {
String columnName = ((SystemColumnHandle) entry.getKey()).getColumnName();
newConstraints.put(columnsByName.get(columnName), entry.getValue());
}
TupleDomain<Integer> newContraint = withColumnDomains(newConstraints.build());
try {
return new MappedPageSource(systemTable.pageSource(systemTransaction.getConnectorTransactionHandle(), session, newContraint), userToSystemFieldIndex.build());
}
catch (UnsupportedOperationException e) {
return new RecordPageSource(new MappedRecordSet(toRecordSet(systemTransaction.getConnectorTransactionHandle(), systemTable, session, newContraint), userToSystemFieldIndex.build()));
}
}
private static RecordSet toRecordSet(ConnectorTransactionHandle sourceTransaction, SystemTable table, ConnectorSession session, TupleDomain<Integer> constraint)
{
return new RecordSet()
{
private final List<Type> types = table.getTableMetadata().getColumns().stream()
.map(ColumnMetadata::getType)
.collect(toImmutableList());
@Override
public List<Type> getColumnTypes()
{
return types;
}
@Override
public RecordCursor cursor()
{
return table.cursor(sourceTransaction, session, constraint);
}
};
}
}