Java tutorial
/* * 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 io.prestosql.connector.system; import com.google.common.collect.ImmutableSet; import io.prestosql.spi.connector.ConnectorSession; import io.prestosql.spi.connector.SchemaTableName; import io.prestosql.spi.connector.SystemTable; import java.util.Map; import java.util.Optional; import java.util.Set; import static com.google.common.collect.ImmutableMap.toImmutableMap; import static java.util.function.Function.identity; public class StaticSystemTablesProvider implements SystemTablesProvider { private final Set<SystemTable> systemTables; private final Map<SchemaTableName, SystemTable> systemTablesMap; public StaticSystemTablesProvider(Set<SystemTable> systemTables) { this.systemTables = ImmutableSet.copyOf(systemTables); this.systemTablesMap = systemTables.stream() .collect(toImmutableMap(table -> table.getTableMetadata().getTable(), identity())); } @Override public Set<SystemTable> listSystemTables(ConnectorSession session) { return systemTables; } @Override public Optional<SystemTable> getSystemTable(ConnectorSession session, SchemaTableName tableName) { return Optional.ofNullable(systemTablesMap.get(tableName)); } }