SystemAdmin (samza-api 1.7.0-SNAPSHOT API)

All Known Implementing Classes:

SinglePartitionWithoutOffsetsSystemAdmin
```
public interface SystemAdmin
```
Helper interface attached to an underlying system to fetch information about streams, partitions, offsets, etc. This interface is useful for providing utility methods that Samza needs in order to interact with a system.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`default boolean`	`clearStream(StreamSpec streamSpec)` Clear the entire stream described by the spec.
`default boolean`	`createStream(StreamSpec streamSpec)` Create a stream described by the spec.
`default void`	`deleteMessages(java.util.Map<SystemStreamPartition,java.lang.String> offsets)` Delete records up to (and including) the provided ssp offsets for all system stream partitions specified in the map
`default java.util.Set<SystemStream>`	`getAllSystemStreams()` Fetch the set of all available streams
`java.util.Map<SystemStreamPartition,java.lang.String>`	`getOffsetsAfter(java.util.Map<SystemStreamPartition,java.lang.String> offsets)` Fetches the offsets for the messages immediately after the supplied offsets for a group of SystemStreamPartitions.
`default java.util.Map<SystemStreamPartition,SystemStreamMetadata.SystemStreamPartitionMetadata>`	`getSSPMetadata(java.util.Set<SystemStreamPartition> ssps)` Fetch metadata from a system for a set of SSPs.
`java.util.Map<java.lang.String,SystemStreamMetadata>`	`getSystemStreamMetadata(java.util.Set<java.lang.String> streamNames)` Fetch metadata from a system for a set of streams.
`default java.util.Map<java.lang.String,SystemStreamMetadata>`	`getSystemStreamPartitionCounts(java.util.Set<java.lang.String> streamNames, long cacheTTL)` Get partitions counts only.
`default boolean`	`isStopped()` To give the status of current systemAdmin
`java.lang.Integer`	`offsetComparator(java.lang.String offset1, java.lang.String offset2)` Compare the two offsets.
`default java.lang.String`	`resolveStartpointToOffset(SystemStreamPartition systemStreamPartition, Startpoint startpoint)` Resolves the startpoint to a system specific offset.
`default void`	`start()`
`default void`	`stop()`
`default void`	`validateStream(StreamSpec streamSpec)` Validates the stream described by the streamSpec on the system.

- Method Detail
  - start
```
default void start()
```
  - stop
```
default void stop()
```
  - isStopped
```
default boolean isStopped()
```
    To give the status of current systemAdmin
    
    Returns:
    
    boolean stopped or not;
  - getOffsetsAfter
```
java.util.Map<SystemStreamPartition,java.lang.String> getOffsetsAfter(java.util.Map<SystemStreamPartition,java.lang.String> offsets)
```
    Fetches the offsets for the messages immediately after the supplied offsets for a group of SystemStreamPartitions.
    
    Parameters:
    
    offsets - Map from SystemStreamPartition to current offsets.
    
    Returns:
    
    Map from SystemStreamPartition to offsets immediately after the current offsets.
  - getSystemStreamMetadata
```
java.util.Map<java.lang.String,SystemStreamMetadata> getSystemStreamMetadata(java.util.Set<java.lang.String> streamNames)
```
    Fetch metadata from a system for a set of streams.
    
    Parameters:
    
    streamNames - The streams to to fetch metadata for.
    
    Returns:
    
    A map from stream name to SystemStreamMetadata for each stream requested in the parameter set.
  - getSSPMetadata
```
default java.util.Map<SystemStreamPartition,SystemStreamMetadata.SystemStreamPartitionMetadata> getSSPMetadata(java.util.Set<SystemStreamPartition> ssps)
```
    Fetch metadata from a system for a set of SSPs. Implementors should override this if there is a more efficient implementation than delegating to getSystemStreamMetadata(java.util.Set<java.lang.String>).
    
    Parameters:
    
    ssps - SSPs for which to get metadata
    
    Returns:
    
    A map from SystemStreamPartition to the SystemStreamPartitionMetadata, with an entry for each SSP in ssps for which metadata could be found
    
    Throws:
    
    java.lang.RuntimeException - if there was an error fetching metadata
  - offsetComparator
```
java.lang.Integer offsetComparator(java.lang.String offset1,
                                   java.lang.String offset2)
```
    Compare the two offsets. -1, 0, +1 means offset1 < offset2, offset1 == offset2 and offset1 > offset2 respectively. Return null if those two offsets are not comparable
    
    Parameters:
    
    offset1 - First offset for comparison.
    
    offset2 - Second offset for comparison.
    
    Returns:
    
    -1 if offset1 < offset2; 0 if offset1 == offset2; 1 if offset1 > offset2. Null if not comparable
  - createStream
```
default boolean createStream(StreamSpec streamSpec)
```
    Create a stream described by the spec.
    
    Parameters:
    
    streamSpec - The spec, or blueprint from which the physical stream will be created on the system.
    
    Returns:
    
    true if the stream was actually created and not pre-existing. false if the stream was pre-existing. A RuntimeException will be thrown if creation fails.
  - validateStream
```
default void validateStream(StreamSpec streamSpec)
                     throws StreamValidationException
```
    Validates the stream described by the streamSpec on the system. A StreamValidationException should be thrown for any validation error.
    
    Parameters:
    
    streamSpec - The spec, or blueprint for the physical stream on the system.
    
    Throws:
    
    StreamValidationException - if validation fails.
  - clearStream
```
default boolean clearStream(StreamSpec streamSpec)
```
    Clear the entire stream described by the spec.
    
    Parameters:
    
    streamSpec - The spec for the physical stream on the system.
    
    Returns:
    
    true if the stream was successfully cleared. false if clearing stream failed.
  - deleteMessages
```
default void deleteMessages(java.util.Map<SystemStreamPartition,java.lang.String> offsets)
```
    Delete records up to (and including) the provided ssp offsets for all system stream partitions specified in the map
    
    Parameters:
    
    offsets - a map from system stream partition to offset
  - getSystemStreamPartitionCounts
```
default java.util.Map<java.lang.String,SystemStreamMetadata> getSystemStreamPartitionCounts(java.util.Set<java.lang.String> streamNames,
                                                                                            long cacheTTL)
```
    Get partitions counts only. Should be more efficient then getSystemStreamMetadata, but if not implemented revert to getSystemStreamMetadata.
    
    Parameters:
    
    streamNames - set of streams to query.
    
    cacheTTL - cacheTTL to use if caching the values.
    
    Returns:
    
    A map from stream name to SystemStreamMetadata for each stream requested in the parameter set.
  - getAllSystemStreams
```
default java.util.Set<SystemStream> getAllSystemStreams()
```
    Fetch the set of all available streams
    
    Returns:
    
    The set of all available SystemStreams.
  - resolveStartpointToOffset
```
default java.lang.String resolveStartpointToOffset(SystemStreamPartition systemStreamPartition,
                                                   Startpoint startpoint)
```
    Resolves the startpoint to a system specific offset.
    
    Parameters:
    
    startpoint - represents the startpoint.
    
    systemStreamPartition - represents the system stream partition.
    
    Returns:
    
    the resolved offset.

Interface SystemAdmin

Method Summary

Method Detail

start

stop

isStopped

getOffsetsAfter

getSystemStreamMetadata

getSSPMetadata

offsetComparator

createStream

validateStream

clearStream

deleteMessages

getSystemStreamPartitionCounts

getAllSystemStreams

resolveStartpointToOffset