Package ch.tocco.nice2.persist.core.api.exec.tasks2

Class GroupbyTask

java.lang.Object

ch.tocco.nice2.persist.core.api.exec.tasks2.GroupbyTask

All Implemented Interfaces:

OptionalTask<EntityList,com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity>>, PersistTask<EntityList,com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity>>

public final class GroupbyTask
extends Object
implements OptionalTask<EntityList,com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity>>

This task partitions a given entity list according to the result of resolving a path against each entity in the list. A path can "end in" an relation, like `relA.relB`, or in a field like `relA.unique_id` (a single field name is the simplest form). It returns a multi map where the key corresponds to the result of resolving the path against an entity in the list. Thus it is either an entity or the value of some field. The GroupbyTask.Key represents this: either one of GroupbyTask.Key.getEntity() or GroupbyTask.Key.getField() will be present. If the result is `null` then the special key GroupbyTask.Key.NULL is used.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GroupbyTask.Key

Constructor Summary

Constructors

Constructor	Description
GroupbyTask(Path path)
GroupbyTask(String path)

Method Summary

Modifier and Type	Method	Description
com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity>	doRun(EntityList entityHolders, CommandContext ctx)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface ch.tocco.nice2.persist.core.api.exec.OptionalTask

run

Methods inherited from interface ch.tocco.nice2.persist.core.api.exec.PersistTask

andThenDo, compose, compose2, composeWhen, discardResult, expand, expand, getDescription, ifElse, logTime, orWhen, orWhenNot, passWhen, passWhenNot, skipErrors, unwrap

Constructor Details

GroupbyTask

public GroupbyTask(Path path)

GroupbyTask

public GroupbyTask(String path)

Method Details

doRun

public com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity> doRun(EntityList entityHolders,
 CommandContext ctx)
                                                                          throws Exception

Specified by:

doRun in interface OptionalTask<EntityList,com.google.common.collect.ImmutableMultimap<GroupbyTask.Key,Entity>>

Throws:

Exception