Package com.almworks.jira.structure.api.forest

Class ForestChange

Object

ForestChange

Direct Known Subclasses:

ForestChange.Add, ForestChange.Move, ForestChange.Remove, ForestChange.Reorder

@PublicApi
@Immutable
public abstract class ForestChange
extends Object

ForestChange represents a single change on a forest. A list of ForestChanges represent a difference between two forests. ForestChanges are used only to represent the difference - to optimize event processing, traffic and to provide data to make visual cues about the change. ForestChanges are not used to record history or provide additional information about the forest.

There are several types of the operations, all defined as the inner classes of ForestChange:

• ForestChange.Add - add operation
• ForestChange.Move - move operation
• ForestChange.Remove - remove operation
• ForestChange.Reorder - reorder operation

Note that Reorder operation can be expressed as a series of Move operations. Structure can use either one Reorder or several Move changes to express reordering.

All classes are immutable.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ForestChange.Add	Represents addition to the forest.
static class	ForestChange.Move	Represents moving one or more rows from their current places in forest under the specified position.
static class	ForestChange.Remove	Represents removal of one or more rows.
static class	ForestChange.Reorder	Represents a complete reorder of the direct children of a given row.
static interface	ForestChange.Visitor	The interface to use when making different actions depending on the specific type of the change.

Method Summary

Modifier and Type	Method	Description
abstract void	accept(ForestChange.Visitor visitor)	Apply the change to the visitor
static ForestChange	add(long under, long after, Forest added)	Creates an "add" forest change.
abstract void	apply(ArrayForest forest)	Given mutable forest, apply the change to it.
static ForestChange	move(long under, long after, LongList rows)	Creates a "move" forest change.
static ForestChange	remove(LongList rows)	Creates a "remove" forest change.
static ForestChange	reorder(long under, LongList children)	Creates a "reorder" forest change.

Methods inherited from class Object

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

Method Details

add

public static ForestChange add(long under,
 long after,
 Forest added)

Creates an "add" forest change.

Parameters:

under - the row under which the addition took place, or 0 if added at the top level

after - the previous sibling to the first added row, or 0 if added as a first row under the parent

added - forest that was added

Returns:

change

move

public static ForestChange move(long under,
 long after,
 LongList rows)

Creates a "move" forest change.

Parameters:

under - the row under which the moved rows were placed

after - the row after which the moved rows were placed

rows - a list of rows that were moved

Returns:

change

remove

public static ForestChange remove(LongList rows)

Creates a "remove" forest change.

Parameters:

rows - a list of rows that were removed from the forest

Returns:

change

reorder

public static ForestChange reorder(long under,
 LongList children)

Creates a "reorder" forest change.

Parameters:

under - the row under which the reordering took place, or 0 if added at the top level

children - row IDs of the children, in the desired new order

Returns:

change

apply

public abstract void apply(@NotNull
 ArrayForest forest)

Given mutable forest, apply the change to it.

Parameters:

forest - forest to change

accept

public abstract void accept(ForestChange.Visitor visitor)

Apply the change to the visitor

Parameters:

visitor - receiver of the call based on the type of this change