/**
* 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.drill.exec.store.sys;
import java.io.IOException;
import java.util.List;
import java.util.Set;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.drill.common.JSONOptions;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.common.logical.StoragePluginConfig;
import org.apache.drill.exec.physical.base.AbstractGroupScan;
import org.apache.drill.exec.planner.logical.DrillTable;
import org.apache.drill.exec.server.DrillbitContext;
import org.apache.drill.exec.store.AbstractSchema;
import org.apache.drill.exec.store.AbstractStoragePlugin;
import org.apache.drill.exec.store.SchemaConfig;
import org.apache.drill.exec.store.pojo.PojoDataType;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
/**
* A "storage" plugin for system tables.
*/
public class SystemTablePlugin extends AbstractStoragePlugin {
// private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(SystemTablePlugin.class);
public static final String SYS_SCHEMA_NAME = "sys";
private final DrillbitContext context;
private final String name;
private final SystemTablePluginConfig config;
private final SystemSchema schema = new SystemSchema();
public SystemTablePlugin(SystemTablePluginConfig config, DrillbitContext context, String name) {
this.config = config;
this.context = context;
this.name = name;
}
@Override
public StoragePluginConfig getConfig() {
return config;
}
@JsonIgnore
public DrillbitContext getContext() {
return this.context;
}
@Override
public void registerSchemas(SchemaConfig schemaConfig, SchemaPlus parent) throws IOException {
parent.add(schema.getName(), schema);
}
@Override
public AbstractGroupScan getPhysicalScan(String userName, JSONOptions selection, List<SchemaPath> columns)
throws IOException {
SystemTable table = selection.getWith(context.getLpPersistence(), SystemTable.class);
return new SystemTableScan(table, this);
}
/**
* This class defines a namespace for {@link org.apache.drill.exec.store.sys.SystemTable}s
*/
private class SystemSchema extends AbstractSchema {
private final Set<String> tableNames;
public SystemSchema() {
super(ImmutableList.<String>of(), SYS_SCHEMA_NAME);
Set<String> names = Sets.newHashSet();
for (SystemTable t : SystemTable.values()) {
names.add(t.getTableName());
}
this.tableNames = ImmutableSet.copyOf(names);
}
@Override
public Set<String> getTableNames() {
return tableNames;
}
@Override
public DrillTable getTable(String name) {
for (SystemTable table : SystemTable.values()) {
if (table.getTableName().equalsIgnoreCase(name)) {
return new StaticDrillTable(SystemTablePlugin.this.name, SystemTablePlugin.this, TableType.SYSTEM_TABLE,
table, new PojoDataType(table.getPojoClass()));
}
}
return null;
}
@Override
public String getTypeName() {
return SystemTablePluginConfig.NAME;
}
}
}