Package org.apache.accumulo.core.iterators

Interface IteratorEnvironment

public interface IteratorEnvironment

Method Summary

Modifier and Type	Method	Description
default IteratorEnvironment	cloneWithSamplingEnabled()	Returns a new iterator environment object that can be used to create deep copies over sample data.
default Authorizations	getAuthorizations()	Return the Scan Authorizations used in this Iterator.
default IteratorUtil.IteratorScope	getIteratorScope()	Return the executed scope of the Iterator.
default PluginEnvironment	getPluginEnv()	Returns an object containing information about the server where this iterator was run.
default SamplerConfiguration	getSamplerConfiguration()
default TableId	getTableId()	Return the table Id associated with this iterator.
default boolean	isFullMajorCompaction()	Return true if the compaction is a full major compaction.
default boolean	isRunningLowOnMemory()	Return whether or not the server is running low on memory
default boolean	isSamplingEnabled()	There are at least two conditions under which sampling will be enabled for an environment.
default boolean	isUserCompaction()	True if compaction was user initiated.

Method Details

getIteratorScope

default IteratorUtil.IteratorScope getIteratorScope()

Return the executed scope of the Iterator. Value will be one of the following: IteratorUtil.IteratorScope.scan, IteratorUtil.IteratorScope.minc, IteratorUtil.IteratorScope.majc

isFullMajorCompaction

default boolean isFullMajorCompaction()

Return true if the compaction is a full major compaction. Will throw IllegalStateException if getIteratorScope() != IteratorUtil.IteratorScope.majc.

getAuthorizations

default Authorizations getAuthorizations()

Return the Scan Authorizations used in this Iterator. Will throw UnsupportedOperationException if getIteratorScope() != IteratorUtil.IteratorScope.scan.

cloneWithSamplingEnabled

default IteratorEnvironment cloneWithSamplingEnabled()

Returns a new iterator environment object that can be used to create deep copies over sample data. The new object created will use the current sampling configuration for the table. The existing iterator environment object will not be modified.

Since sample data could be created in many different ways, a good practice for an iterator is to verify the sampling configuration is as expected.

 
   class MyIter implements SortedKeyValueIterator<Key,Value> {
     SortedKeyValueIterator<Key,Value> source;
     SortedKeyValueIterator<Key,Value> sampleIter;
     @Override
     void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options,
       IteratorEnvironment env) {
       IteratorEnvironment sampleEnv = env.cloneWithSamplingEnabled();
       //do some sanity checks on sampling config
       validateSamplingConfiguration(sampleEnv.getSamplerConfiguration());
       sampleIter = source.deepCopy(sampleEnv);
       this.source = source;
     }
   }
 
 

Throws:

SampleNotPresentException - when sampling is not configured for table.

Since:

1.8.0

isSamplingEnabled

default boolean isSamplingEnabled()

There are at least two conditions under which sampling will be enabled for an environment. One condition is when sampling is enabled for the scan that starts everything. Another possibility is for a deep copy created with an environment created by calling cloneWithSamplingEnabled()

Returns:

true if sampling is enabled for this environment.

Since:

1.8.0

getSamplerConfiguration

default SamplerConfiguration getSamplerConfiguration()

Returns:

sampling configuration is sampling is enabled for environment, otherwise returns null.

Since:

1.8.0

isUserCompaction

default boolean isUserCompaction()

True if compaction was user initiated.

Since:

2.0.0

getPluginEnv

default PluginEnvironment getPluginEnv()

Returns an object containing information about the server where this iterator was run. To obtain a table configuration, use the following methods:

 iterEnv.getPluginEnv().getConfiguration(env.getTableId())
 

Since:

2.1.0

getTableId

default TableId getTableId()

Return the table Id associated with this iterator.

Since:

2.0.0

isRunningLowOnMemory

default boolean isRunningLowOnMemory()

Return whether or not the server is running low on memory

Returns:

true if server is running low on memory

Since:

3.0.0