Package com.clickhouse.client

Interface ClickHouseResponse

All Superinterfaces:

AutoCloseable, Serializable

All Known Implementing Classes:

ClickHouseSimpleResponse, ClickHouseStreamResponse

public interface ClickHouseResponse
extends AutoCloseable, Serializable

This encapsulates a server reponse. Depending on concrete implementation, it could be either an in-memory list or a wrapped input stream with ClickHouseDataProcessor attached for deserialization. To get data returned from server, depending on actual needs, you have 3 options:

• use records() or stream() to get deserialized ClickHouseRecord one at a time
• use firstRecord() if you're certain that all you need is the first ClickHouseRecord
• use getInputStream() or pipe(OutputStream, int) if you prefer to handle stream instead of deserialized data

Field Summary

Fields

Modifier and Type	Field	Description
static final ClickHouseResponse	EMPTY	Empty response that can never be closed.

Method Summary

Modifier and Type	Method	Description
void	close()
default ClickHouseRecord	firstRecord()	Gets the first record only.
default <T> T	firstRecord(Class<T> objClass)	Gets the first record as mapped object.
List<ClickHouseColumn>	getColumns()	Gets list of columns.
ClickHouseInputStream	getInputStream()	Gets input stream of the response.
ClickHouseResponseSummary	getSummary()	Gets summary of this response.
boolean	isClosed()	Checks whether the response has been closed or not.
default void	pipe(OutputStream output, int bufferSize)	Pipes the contents of this response into the given output stream.
Iterable<ClickHouseRecord>	records()	Returns an iterable collection of records which can be walked through in a foreach loop.
<T> Iterable<T>	records(Class<T> objClass)	Returns an iterable collection of mapped objects which can be walked through in a foreach loop.
default Stream<ClickHouseRecord>	stream()	Gets stream of records to process.
default <T> Stream<T>	stream(Class<T> objClass)	Gets stream of mapped objects to process.

Field Details

EMPTY

static final ClickHouseResponse EMPTY

Empty response that can never be closed.

Method Details

getColumns

List<ClickHouseColumn> getColumns()

Gets list of columns.

Returns:

non-null list of column

getSummary

ClickHouseResponseSummary getSummary()

Gets summary of this response. Keep in mind that the summary may change over time until response is closed.

Returns:

non-null summary of this response

getInputStream

ClickHouseInputStream getInputStream()

Gets input stream of the response. In general, this is the most memory-efficient way for streaming data from server to client. However, this also means additional work is required for deserialization, especially when using a binary format.

Returns:

non-null input stream for getting raw data returned from server

firstRecord

default ClickHouseRecord firstRecord()

Gets the first record only. Please use records() instead if you need to access the rest of records.

Returns:

the first record

Throws:

NoSuchElementException - when there's no record at all

UncheckedIOException - when failed to read data(e.g. deserialization)

firstRecord

default <T> T firstRecord(Class<T> objClass)

Gets the first record as mapped object. Please use records(Class) instead if you need to access the rest of records.

Type Parameters:

T - type of the mapped object

Parameters:

objClass - non-null class of the mapped object

Returns:

mapped object of the first record

Throws:

NoSuchElementException - when there's no record at all

UncheckedIOException - when failed to read data(e.g. deserialization)

records

Iterable<ClickHouseRecord> records()

Returns an iterable collection of records which can be walked through in a foreach loop. Please pay attention that: 1) UncheckedIOException might be thrown when iterating through the collection; and 2) it's not supposed to be called for more than once.

Returns:

non-null iterable collection

Throws:

UncheckedIOException - when failed to read data(e.g. deserialization)

records

<T> Iterable<T> records(Class<T> objClass)

Returns an iterable collection of mapped objects which can be walked through in a foreach loop. When objClass is null or ClickHouseRecord, it's same as calling records().

Type Parameters:

T - type of the mapped object

Parameters:

objClass - non-null class of the mapped object

Returns:

non-null iterable collection

Throws:

UncheckedIOException - when failed to read data(e.g. deserialization)

pipe

default void pipe(OutputStream output,
 int bufferSize)
           throws IOException

Pipes the contents of this response into the given output stream. Keep in mind that it's caller's responsibility to flush and close the output stream.

Parameters:

output - non-null output stream, which will remain open

bufferSize - buffer size, 0 or negative value will be treated as ClickHouseClientOption.BUFFER_SIZE

Throws:

IOException - when error occurred reading or writing data

stream

default Stream<ClickHouseRecord> stream()

Gets stream of records to process.

Returns:

stream of records

stream

default <T> Stream<T> stream(Class<T> objClass)

Gets stream of mapped objects to process.

Returns:

stream of mapped objects

close

void close()

Specified by:

close in interface AutoCloseable

isClosed

boolean isClosed()

Checks whether the response has been closed or not.

Returns:

true if the response has been closed; false otherwise