sql/connector/JavaSchemaRequiredDataSource.java

0001 /*
0002  * Licensed to the Apache Software Foundation (ASF) under one or more
0003  * contributor license agreements.  See the NOTICE file distributed with
0004  * this work for additional information regarding copyright ownership.
0005  * The ASF licenses this file to You under the Apache License, Version 2.0
0006  * (the "License"); you may not use this file except in compliance with
0007  * the License.  You may obtain a copy of the License at
0008  *
0009  *    http://www.apache.org/licenses/LICENSE-2.0
0010  *
0011  * Unless required by applicable law or agreed to in writing, software
0012  * distributed under the License is distributed on an "AS IS" BASIS,
0013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
0014  * See the License for the specific language governing permissions and
0015  * limitations under the License.
0016  */
0017
0018 package test.org.apache.spark.sql.connector;
0019
0020 import java.util.Map;
0021
0022 import org.apache.spark.sql.connector.catalog.Table;
0023 import org.apache.spark.sql.connector.catalog.TableProvider;
0024 import org.apache.spark.sql.connector.expressions.Transform;
0025 import org.apache.spark.sql.connector.read.InputPartition;
0026 import org.apache.spark.sql.connector.read.ScanBuilder;
0027 import org.apache.spark.sql.types.StructType;
0028 import org.apache.spark.sql.util.CaseInsensitiveStringMap;
0029
0030 public class JavaSchemaRequiredDataSource implements TableProvider {
0031
0032   class MyScanBuilder extends JavaSimpleScanBuilder {
0033
0034     private StructType schema;
0035
0036     MyScanBuilder(StructType schema) {
0037       this.schema = schema;
0038     }
0039
0040     @Override
0041     public StructType readSchema() {
0042       return schema;
0043     }
0044
0045     @Override
0046     public InputPartition[] planInputPartitions() {
0047       return new InputPartition[0];
0048     }
0049   }
0050
0051   @Override
0052   public boolean supportsExternalMetadata() {
0053     return true;
0054   }
0055
0056   @Override
0057   public StructType inferSchema(CaseInsensitiveStringMap options) {
0058     throw new IllegalArgumentException("requires a user-supplied schema");
0059   }
0060
0061   @Override
0062   public Table getTable(
0063       StructType schema, Transform[] partitioning, Map<String, String> properties) {
0064     return new JavaSimpleBatchTable() {
0065
0066       @Override
0067       public StructType schema() {
0068         return schema;
0069       }
0070
0071       @Override
0072       public ScanBuilder newScanBuilder(CaseInsensitiveStringMap options) {
0073         return new MyScanBuilder(schema);
0074       }
0075     };
0076   }
0077 }