Calcite-[5]-example-csv简析

一 源码下载

参照下文，下载编译源码

Calcite-[1]-Tutorial

运行CsvTest 总体感知csv样例工程

输出

Test ignored.FredEricJohnWilmaAlice100, Fred, 10, , , 30, 25, true, false, 1996-08-03110, Eric, 20, M, San Francisco, 3, 80, null, false, 2001-01-01110, John, 40, M, Vancouver, 2, null, false, true, 2002-05-03120, Wilma, 20, F, , 1, 5, null, true, 2005-09-07130, Alice, 40, F, Vancouver, 2, null, false, true, 2007-01-01FredEricJohnWilmaAliceTest ignored.SalesMarketingAccounts100, Fred, 10, , , 30, 25, true, false, 1996-08-03110, Eric, 20, M, San Francisco, 3, 80, null, false, 2001-01-01110, John, 40, M, Vancouver, 2, null, false, true, 2002-05-03120, Wilma, 20, F, , 1, 5, null, true, 2005-09-07130, Alice, 40, F, Vancouver, 2, null, false, true, 2007-01-01100, Fred, 10, , , 30, 25, true, false, 1996-08-03110, Eric, 20, M, San Francisco, 3, 80, null, false, 2001-01-01110, John, 40, M, Vancouver, 2, null, false, true, 2002-05-03120, Wilma, 20, F, , 1, 5, null, true, 2005-09-07130, Alice, 40, F, Vancouver, 2, null, false, true, 2007-01-01

二、简析1-model.json

model.json

{  "version": "1.0",  "defaultSchema": "SALES",  "schemas": [    {      "name": "SALES",      "type": "custom",      "factory": "org.apache.calcite.adapter.csv.CsvSchemaFactory",      "operand": {        "directory": "sales" }    }  ]}

（1）CsvSchemaFactory
CsvSchemaFactory根据directory构建CsvSchema
CsvSchemaFactory::create
根据json中的directory和flavor 构建一个CsvSchema(directoryFile, flavor);

简要如下：

public class CsvSchemaFactory implements SchemaFactory { public static final CsvSchemaFactory INSTANCE = new CsvSchemaFactory();  private CsvSchemaFactory() {  }  public Schema create(SchemaPlus parentSchema, String name,      Map<String, Object> operand) {    final String directory = (String) operand.get("directory");    File directoryFile = new File(directory);    String flavorName = (String) operand.get("flavor");    CsvTable.Flavor flavor = CsvTable.Flavor.SCANNABLE;    return new CsvSchema(directoryFile, flavor);  }}
（2）CsvSchema
CsvSchema：Schema mapped onto a directory of CSV files. Each table in the schema is a CSV file in that directory.
将文件和table做个映射，每个文件映射为一个table

public class CsvSchema extends AbstractSchema {  private final File directoryFile;  private final CsvTable.Flavor flavor;  private Map<String, Table> tableMap;

CsvSchema::createTableMap private Map<String, Table> createTableMap()        主要根据目录遍历所有 ".csv", ".csv.gz", ".json", ".json.gz"，对遍历的文件，调用createTable构建表CsvSchema::createTable   调用 CsvTranslatableTable or CsvScannableTable or CsvFilterableTable构建表