Github user xubo245 commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2337#discussion_r190825696
--- Diff: docs/sdk-guide.md ---
@@ -398,3 +399,160 @@ Reference : [list of carbon properties](
http://carbondata.apache.org/configurati */
public static org.apache.carbondata.sdk.file.Schema getCarbonSchemaFromAvroSchema(String avroSchemaString);
```
+# SDK Reader
+This SDK reader reads CarbonData file and carbonindex file at a given path.
+External client can make use of this reader to read CarbonData files without CarbonSession.
+## Quick example
+```
+ // 1. Create carbon reader
+ String path = "./testWriteFiles";
+ CarbonReader reader = CarbonReader
+ .builder(path, "_temp")
+ .projection(new String[]{"name", "age"})
+ .build();
+
+ // 2. Read data
+ int i = 0;
+ while (reader.hasNext()) {
+ Object[] row = (Object[]) reader.readNextRow();
+ System.out.println(row[0] + "\t" + row[1]);
+ i++;
+ }
+
+ // 3. Close this reader
+ reader.close();
+```
+
+Find example code at [CarbonReaderExample](
https://github.com/apache/carbondata/blob/master/examples/spark2/src/main/java/org/apache/carbondata/examples/sdk/CarbonReaderExample.java) in the CarbonData repo.
+
+## API List
+
+### org.apache.carbondata.sdk.file.CarbonReader
+```
+ /**
+ * Return a new CarbonReaderBuilder instance
+ */
+ public static CarbonReaderBuilder builder(String tablePath, String tableName);
+```
+
+```
+ /**
+ * Read carbondata file and return the schema
+ */
+ public static List<ColumnSchema> readSchemaInDataFile(String dataFilePath);
+```
+
+```
+ /**
+ * Read schema file and return table info object
+ */
+ public static TableInfo readSchemaFile(String schemaFilePath);
+```
+
+```
+ /**
+ * Return true if has next row
+ */
+ public boolean hasNext();
+```
+
+```
+ /**
+ * Read and return next row object
+ */
+ public T readNextRow();
+```
+
+```
+ /**
+ * Close reader
+ */
+ public void close();
+```
+
+###org.apache.carbondata.sdk.file.CarbonReaderBuilder
+```
+ /**
+ * Construct a CarbonReaderBuilder with table path and table name
+ *
+ * @param tablePath table path
+ * @param tableName table name
+ */
+ CarbonReaderBuilder(String tablePath, String tableName);
+```
+
+```
+ /**
+ * Configure the projection column names of carbon reader
+ *
+ * @param projectionColumnNames projection column names
+ * @return CarbonReaderBuilder object
+ */
+ public CarbonReaderBuilder projection(String[] projectionColumnNames);
+```
+
+```
+ /**
+ * Configure the transactional status of table
+ *
+ * @param isTransactionalTable whether is transactional table or not
+ * @return CarbonReaderBuilder object
+ */
+ public CarbonReaderBuilder isTransactionalTable(boolean isTransactionalTable);
+```
+
+```
+ /**
+ * Configure the filter expression for carbon reader
+ *
+ * @param filterExpression filter expression
+ * @return CarbonReaderBuilder object
+ */
+ public CarbonReaderBuilder filter(Expression filterExpression);
+```
+
+```
+ /**
+ * Set the access key for S3
+ *
+ * @param key the string of access key for different S3 type,like: fs.s3a.access.key
+ * @param value the value of access key
+ * @return CarbonWriterBuilder
+ */
+ public CarbonReaderBuilder setAccessKey(String key, String value);
+```
+
+```
+ /**
+ * Set the secret key for S3
+ *
+ * @param key the string of secret key for different S3 type,like: fs.s3a.secret.key
+ * @param value the value of secret key
+ * @return CarbonWriterBuilder
+ */
+ public CarbonReaderBuilder setSecretKey(String key, String value);
+```
+
+```
+ /**
+ * Set the endpoint for S3
+ *
+ * @param key the string of endpoint for different S3 type,like: fs.s3a.endpoint
+ * @param value the value of endpoint
+ * @return CarbonWriterBuilder
+ */
+ public CarbonReaderBuilder setEndPoint(String key, String value);
--- End diff --
ok, AK and SK also have another interface
---
Locked
