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 com.facebook.presto.archiveConnector; import com.google.common.base.Function; import com.google.common.base.Supplier; import com.google.common.base.Suppliers; import com.google.common.base.Throwables; import com.google.common.collect.ImmutableMap; import com.google.common.collect.ImmutableSet; import com.google.common.io.Resources; import io.airlift.json.JsonCodec; import javax.inject.Inject; import java.io.IOException; import java.net.URI; import java.net.URL; import java.util.List; import java.util.Map; import java.util.Set; import static com.google.common.collect.Iterables.transform; import static com.google.common.collect.Maps.transformValues; import static com.google.common.collect.Maps.uniqueIndex; import static java.nio.charset.StandardCharsets.UTF_8; import static java.util.Objects.requireNonNull; public class ArchiveClient { /** * SchemaName -> (TableName -> TableMetadata) */ private final Supplier<Map<String, Map<String, ArchiveTable>>> schemas; private final ArchiveConfig config; @Inject public ArchiveClient(ArchiveConfig config, JsonCodec<Map<String, List<ArchiveTable>>> catalogCodec) throws IOException { requireNonNull(config, "config is null"); requireNonNull(catalogCodec, "catalogCodec is null"); schemas = Suppliers.memoize(schemasSupplier(catalogCodec, config.getMetadata())); this.config = config; /* inputFilesInfo = config.getInputFilesInfo(); transformInfo = config.getTransformInfo();*/ } public Set<String> getSchemaNames() { return schemas.get().keySet(); } public Set<String> getTableNames(String schema) { requireNonNull(schema, "schema is null"); Map<String, ArchiveTable> tables = schemas.get().get(schema); if (tables == null) { return ImmutableSet.of(); } return tables.keySet(); } public ArchiveTable getTable(String schema, String tableName) { requireNonNull(schema, "schema is null"); requireNonNull(tableName, "tableName is null"); Map<String, ArchiveTable> tables = schemas.get().get(schema); if (tables == null) { return null; } return tables.get(tableName); } private static Supplier<Map<String, Map<String, ArchiveTable>>> schemasSupplier( final JsonCodec<Map<String, List<ArchiveTable>>> catalogCodec, final URI metadataUri) { return () -> { try { return lookupSchemas(metadataUri, catalogCodec); } catch (IOException e) { throw Throwables.propagate(e); } }; } private static Map<String, Map<String, ArchiveTable>> lookupSchemas(URI metadataUri, JsonCodec<Map<String, List<ArchiveTable>>> catalogCodec) throws IOException { URL result = metadataUri.toURL(); String json = Resources.toString(result, UTF_8); Map<String, List<ArchiveTable>> catalog = catalogCodec.fromJson(json); return ImmutableMap.copyOf(transformValues(catalog, resolveAndIndexTables(metadataUri))); } private static Function<List<ArchiveTable>, Map<String, ArchiveTable>> resolveAndIndexTables( final URI metadataUri) { return tables -> { Iterable<ArchiveTable> resolvedTables = transform(tables, tableUriResolver(metadataUri)); return ImmutableMap.copyOf(uniqueIndex(resolvedTables, ArchiveTable::getName)); }; } private static Function<ArchiveTable, ArchiveTable> tableUriResolver(final URI baseUri) { return table -> { return new ArchiveTable(table.getName(), table.getColumns()); }; } public ArchiveConfig getConfig() { return config; } /* public String getInputFilesInfo() { return config.getInputFilesInfo(); } public String getTransformInfo() { return config.getTransformInfo(); }*/ }