it.tidalwave.util.spi
Class FinderSupport<Type,ExtendedFinder extends Finder<Type>>

java.lang.Object
  it.tidalwave.util.spi.FinderSupport<Type,ExtendedFinder>

All Implemented Interfaces:

Finder<Type>, java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:

Composite.EmptyFinder, SimpleFinderSupport

public abstract class FinderSupport<Type,ExtendedFinder extends Finder<Type>>
extends java.lang.Object
implements Finder<Type>, java.lang.Cloneable

A support class for implementing a Finder. Subclasses only need to implement the computeResults() method where raw results are retrieved (with raw we mean that they shouldn't be filtered or sorted, as post-processing will be performed by this class) and a clone constructor. If you don't need to extend the Finder with extra methods, please use the simplified SimpleFinderSupport.

Version:

$Id$

Author:

Fabrizio Giudici

See Also:

Serialized Form

Status: draft API

Nested Class Summary

Nested classes/interfaces inherited from interface it.tidalwave.util.Finder

Finder.FilterSortCriterion<Type>, Finder.SortCriterion, Finder.SortDirection

Field Summary

protected int	firstResult
protected int	maxResults
protected java.util.List<it.tidalwave.util.spi.FinderSupport.Sorter<Type>>	sorters

Constructor Summary

protected	FinderSupport()
protected	FinderSupport(java.lang.String name) Creates an instance with the given name (that will be used for diagnostics).

Method Summary

FinderSupport<Type,ExtendedFinder>	clone() Clones this object.
protected java.util.List<? extends Type>	computeNeededResults() Subclasses can implement this method where *only the requested* raw results must be retrieved.
protected java.util.List<? extends Type>	computeResults() Subclasses can implement this method where *all* the raw results must be actually retrieved.
int	count() Performs the search and returns the count of found items.
Type	firstResult() Performs the search and returns only the first found item.
ExtendedFinder	from(int firstResult) Tells the Finder that only a subset of found items will be returned, starting from the given position.
ExtendedFinder	max(int maxResults) Tells the Finder that only a maximum number of found items will be returned.
<AnotherType> Finder<AnotherType>	ofType(java.lang.Class<AnotherType> type)
Type	result() Performs the search assuming that it will return a single item and returns it.
java.util.List<? extends Type>	results() Performs the search and returns the found items.
ExtendedFinder	sort(Finder.SortCriterion criterion) Tells the Finder that results will be sorted according to the given criterion, in ascending direction.
ExtendedFinder	sort(Finder.SortCriterion criterion, Finder.SortDirection direction) Tells the Finder that results will be sorted according to the given criterion and direction.

Methods inherited from class java.lang.Object

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

Field Detail

firstResult

@Nonnegative
protected int firstResult

maxResults

@Nonnegative
protected int maxResults

sorters

@Nonnull
protected java.util.List<it.tidalwave.util.spi.FinderSupport.Sorter<Type>> sorters

Constructor Detail

FinderSupport

protected FinderSupport(@Nonnull
                        java.lang.String name)

Creates an instance with the given name (that will be used for diagnostics).

Parameters:

name - the name

FinderSupport

protected FinderSupport()

Method Detail

clone

@Nonnull
public FinderSupport<Type,ExtendedFinder> clone()

Clones this object. This operation is called whenever a parameter-setting method is called in fluent-interface style.

Overrides:

clone in class java.lang.Object

Returns:

the cloned object

from

@Nonnull
public ExtendedFinder from(@Nonnegative
                                   int firstResult)

Tells the Finder that only a subset of found items will be returned, starting from the given position.

Specified by:

from in interface Finder<Type>

Returns:

the Finder

max

@Nonnull
public ExtendedFinder max(@Nonnegative
                                  int maxResults)

Tells the Finder that only a maximum number of found items will be returned.

Specified by:

max in interface Finder<Type>

Returns:

the Finder

ofType

@Nonnull
public <AnotherType> Finder<AnotherType> ofType(@Nonnull
                                                        java.lang.Class<AnotherType> type)

Specified by:

ofType in interface Finder<Type>

Returns:

the Finder

sort

@Nonnull
public ExtendedFinder sort(@Nonnull
                                   Finder.SortCriterion criterion,
                                   @Nonnull
                                   Finder.SortDirection direction)

Tells the Finder that results will be sorted according to the given criterion and direction.

Specified by:

sort in interface Finder<Type>

Parameters:

criterion - the sort criterion

direction - the sort direction

Returns:

the Finder

sort

@Nonnull
public final ExtendedFinder sort(@Nonnull
                                         Finder.SortCriterion criterion)

Tells the Finder that results will be sorted according to the given criterion, in ascending direction.

Specified by:

sort in interface Finder<Type>

Parameters:

criterion - the sort criterion

Returns:

the Finder

result

@Nonnull
public Type result()
            throws NotFoundException

Performs the search assuming that it will return a single item and returns it. This method fails if the search returns more than one single item.

Specified by:

result in interface Finder<Type>

Returns:

the found item

Throws:

NotFoundException - if the search didn't find anything

firstResult

@Nonnull
public Type firstResult()
                 throws NotFoundException

Performs the search and returns only the first found item.

Specified by:

firstResult in interface Finder<Type>

Returns:

the first found item

Throws:

NotFoundException - if the search didn't find anything

results

@Nonnull
public java.util.List<? extends Type> results()

Performs the search and returns the found items.

Specified by:

results in interface Finder<Type>

Returns:

the searched items

count

@Nonnegative
public int count()

Performs the search and returns the count of found items.

Specified by:

count in interface Finder<Type>

Returns:

the count of found items

computeResults

@Nonnull
protected java.util.List<? extends Type> computeResults()

Subclasses can implement this method where *all* the raw results must be actually retrieved.

Returns:

the unprocessed results

computeNeededResults

@Nonnull
protected java.util.List<? extends Type> computeNeededResults()

Subclasses can implement this method where *only the requested* raw results must be retrieved.

Returns:

the unprocessed results