sirius.kernel.commons

Class PriorityCollector<T>

java.lang.Object

sirius.kernel.commons.PriorityCollector<T>

Type Parameters:

T - the type of values to be collected

public class PriorityCollector<T>
extends Object

Provides a pull pattern just like DataCollector with an externally supplied order.

When asking methods to create or populate a List it's easier to create and pass along a PriorityCollector instead of having each method creating its own list and joining them afterwards.

Using a PriorityCollector, several methods can be supplied with the same instance and generate a list or a custom (externally) ordering. This greatly simplifies creating extensible systems which are enhanced by sub-components and where order of elements matter. The final list is sorted by comparing the priority. Therefore if a.priority < b.priority then a will occur before b in the list.

If the order of the provided elements does not matter, a DataCollector can be used.

See Also:

DataCollector

Field Summary

Fields

Modifier and Type	Field and Description
protected List<ComparableTuple<Integer,T>>	data
static int	DEFAULT_PRIORITY Provides a default constant which can be used if a collector is pre-populated with standard values and then enhanced by sub modules.

Constructor Summary

Constructors

Constructor and Description
PriorityCollector()

Method Summary

Modifier and Type	Method and Description
void	add(int priority, T entity) Adds the given entity with the given priority.
void	addDefault(T entity) Adds the given entity with the default priority.
static <T> PriorityCollector<T>	create() Creates a new PriorityCollector.
List<T>	getData() Returns the list of added entities sorted by priority.
int	size() Returns the number of items added to this collector.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PRIORITY

public static final int DEFAULT_PRIORITY

Provides a default constant which can be used if a collector is pre-populated with standard values and then enhanced by sub modules.

Using an agreed upon standard value makes it easy for component creators to provide values which will be inserted before or after the default value.

See Also:

Constant Field Values

data

protected List<ComparableTuple<Integer,T>> data

Constructor Detail

PriorityCollector

public PriorityCollector()

Method Detail

create

public static <T> PriorityCollector<T> create()

Creates a new PriorityCollector.

Boilerplate method, so one doesn't need to re-type the type parameters.

Type Parameters:

T - the type of value collect by the collector

Returns:

a new PriorityCollector

add

public void add(int priority,
                T entity)

Adds the given entity with the given priority.

Parameters:

priority - the priority to use for this element.

entity - the entity added to the collector.

addDefault

public void addDefault(T entity)

Adds the given entity with the default priority.

Parameters:

entity - the entity added to the collector.

See Also:

DEFAULT_PRIORITY

getData

public List<T> getData()

Returns the list of added entities sorted by priority.

The comparator used is < - therefore if a.priority < b.priority then a will occur before b in the list.

Returns:

the list of entities ordered by priority ascending

size

public int size()

Returns the number of items added to this collector.

Returns:

the number of items in this collector

toString

public String toString()

Overrides:

toString in class Object