com.neurosys.etl.common.transformers

Class ContextMapperTransformer

java.lang.Object

java.util.AbstractMap<K,V>

java.util.HashMap

com.neurosys.etl.common.transformers.ContextMapperTransformer

All Implemented Interfaces:

FunctionTransformer, Serializable, Cloneable, Function, Map, org.apache.commons.collections.Transformer

public class ContextMapperTransformer
extends HashMap
implements FunctionTransformer

Some Transformation processes require context/Scope with various interdependencies during the transformation process. The main transformation process is unchanged , however during the process some dependent branches of the process may require to tap the context contributed by other sub-transformations.

Map key using the #mapper's Mapper.getFieldName() or Mapper.getBehavior(Class) IntermediateResultMapperBehavior One can use a MapValueLookupTransformer or the more convenient ContextExtractorTransformer to extract back a particular context variable from the context Map.

For standard implementations ensure the Bean created is in THREAD SCOPE

Author:

Arjun Dhar TODO: Add to unit test case with concurrency testing + thread safe

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
ContextMapperTransformer()
ContextMapperTransformer(List<Mapper<org.apache.commons.collections.Transformer>> mappers)

Method Summary

Modifier and Type	Method and Description
Object	get(Object key)
protected Object	getContext(Object key)
List<Mapper<org.apache.commons.collections.Transformer>>	getMappers() List of Mappers that will act on the input to create context variables
Class<Reference>	getReferenceType() The Context can maintain a Strong Reference (null), WeakReference or SoftReference to the elements in it. Define the class if we explicitly want to dictate the type. Note: If threadSafe is true, it is recommended that the either a WeakReference or a SoftReference be adopted.
protected Map	initContext()
boolean	isThreadSafe() If true, ten for each thread a new context is provided
Object	put(Object key, Object value)
protected Object	setContext(Object key, Object value)
void	setMappers(List<Mapper<org.apache.commons.collections.Transformer>> mappers) List of Mappers that will act on the input to create context variables
void	setReferenceType(Class<Reference> referenceType) The Context can maintain a Strong Reference (null), WeakReference or SoftReference to the elements in it. Define the class if we explicitly want to dictate the type. Note: If threadSafe is true, it is recommended that the either a WeakReference or a SoftReference be adopted.
void	setThreadSafe(boolean threadSafe) If true, ten for each thread a new context is provided
Object	transform(Object input)

Methods inherited from class java.util.HashMap

clear, clone, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, forEach, getOrDefault, isEmpty, keySet, merge, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.neurosys.etl.common.transformers.FunctionTransformer

apply

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

ContextMapperTransformer

public ContextMapperTransformer()

ContextMapperTransformer

public ContextMapperTransformer(List<Mapper<org.apache.commons.collections.Transformer>> mappers)

Method Detail

initContext

protected Map initContext()

getContext

protected Object getContext(Object key)

setContext

protected Object setContext(Object key,
                            Object value)

transform

public Object transform(Object input)

Specified by:

transform in interface org.apache.commons.collections.Transformer

getMappers

public List<Mapper<org.apache.commons.collections.Transformer>> getMappers()

List of Mappers that will act on the input to create context variables

setMappers

public void setMappers(List<Mapper<org.apache.commons.collections.Transformer>> mappers)

List of Mappers that will act on the input to create context variables

isThreadSafe

public boolean isThreadSafe()

If true, ten for each thread a new context is provided

Default value:

true

setThreadSafe

public void setThreadSafe(boolean threadSafe)

If true, ten for each thread a new context is provided

Default value:

true

getReferenceType

public Class<Reference> getReferenceType()

The Context can maintain a Strong Reference (null), WeakReference or SoftReference to the elements in it.
Define the class if we explicitly want to dictate the type.

Note: If threadSafe is true, it is recommended that the either a WeakReference or a SoftReference be adopted.

Default value:

null

setReferenceType

public void setReferenceType(Class<Reference> referenceType)

The Context can maintain a Strong Reference (null), WeakReference or SoftReference to the elements in it.
Define the class if we explicitly want to dictate the type.

Note: If threadSafe is true, it is recommended that the either a WeakReference or a SoftReference be adopted.

Default value:

null

put

public Object put(Object key,
                  Object value)

Specified by:

put in interface Map

Overrides:

put in class HashMap

get

public Object get(Object key)

Specified by:

get in interface Map

Overrides:

get in class HashMap