Package it.tidalwave.util.spi

Class HierarchicFinderSupport<T,F extends Finder<T>>

java.lang.Object

it.tidalwave.util.spi.HierarchicFinderSupport<T,F>

All Implemented Interfaces:

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

Direct Known Subclasses:

FinderWithIdSupport, SimpleFinderSupport

public class HierarchicFinderSupport<T,F extends Finder<T>>
extends java.lang.Object
implements Finder<T>

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.

Author:

Fabrizio Giudici

See Also:

Serialized Form

Status: draft API

Nested Class Summary

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

Finder.InMemorySortCriterion<U>, Finder.SortCriterion, Finder.SortDirection

Field Summary

Fields

Modifier and Type	Field	Description
protected int	firstResult
protected int	maxResults

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	HierarchicFinderSupport()	Default constructor.
protected	HierarchicFinderSupport(HierarchicFinderSupport<T,F> other, java.lang.Object holder)	Clone constructor for subclasses.
protected	HierarchicFinderSupport(java.lang.String name)	Creates an instance with the given name (that will be used for diagnostics).

Method Summary

Modifier and Type	Method	Description
HierarchicFinderSupport<T,F>	clone()	Deprecated.
protected F	clone(java.lang.Object override)	Deprecated. Use clonedWith(Object) instead.
protected F	clonedWith(java.lang.Object override)	Create a clone of this object calling the special copy constructor by reflection.
protected java.util.List<T>	computeNeededResults()	Subclasses can implement this method where *only the requested* raw results must be retrieved.
protected java.util.List<T>	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.
F	from(int firstResult)	Tells the Finder that only a subset of found items will be returned, starting from the given position.
protected static <U> U	getSource(java.lang.Class<? extends U> type, U other, java.lang.Object override)	A utility method used by the copy constructor (see general documentation).
F	max(int maxResults)	Tells the Finder that only a maximum number of found items will be returned.
<U> Finder<U>	ofType(java.lang.Class<U> type)	Tells the Finder that the specified type of results is expected.
java.util.List<T>	results()	Performs the search and returns the found items.
F	sort(Finder.SortCriterion criterion)	Tells the Finder that results will be sorted according to the given criterion, in ascending direction.
F	sort(Finder.SortCriterion criterion, Finder.SortDirection direction)	Tells the Finder that results will be sorted according to the given criterion and direction.
F	withContext(java.lang.Object context)	Tells the Finder that results should be created with the given context.

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.tidalwave.util.Finder

firstResult, forEach, from, from, iterator, max, max, optionalFirstResult, optionalResult, result, stream

Field Detail

firstResult

@Nonnegative
protected final int firstResult

maxResults

@Nonnegative
protected final int maxResults

Constructor Detail

HierarchicFinderSupport

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

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

Parameters:

name - the name

HierarchicFinderSupport

protected HierarchicFinderSupport()

Default constructor.

HierarchicFinderSupport

protected HierarchicFinderSupport(@Nonnull
                                  HierarchicFinderSupport<T,F> other,
                                  @Nonnull
                                  java.lang.Object holder)

Clone constructor for subclasses.

Parameters:

other - the other instance to clone

holder - the holder object

Method Detail

clone

@Nonnull
public final HierarchicFinderSupport<T,F> clone()

Deprecated.

This method throws an exception since a Finder extending this class must be cloned with clonedWith(Object).

Overrides:

clone in class java.lang.Object

See Also:

clonedWith(Object)

clonedWith

@Nonnull
protected F clonedWith(@Nonnull
                       java.lang.Object override)

Create a clone of this object calling the special copy constructor by reflection.

Parameters:

override - the override object

Returns:

the clone

clone

@Nonnull
@Deprecated
protected F clone(@Nonnull
                  java.lang.Object override)

Deprecated.

Use clonedWith(Object) instead.

Create a clone of this object calling the special clone constructor by reflection.

Parameters:

override - the override object

Returns:

the clone

from

@Nonnull
public F 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<T>

Parameters:

firstResult - the index of the first result to return

Returns:

the Finder

max

@Nonnull
public F max(@Nonnegative
             int maxResults)

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

Specified by:

max in interface Finder<T>

Parameters:

maxResults - the max number of results to return

Returns:

the Finder

withContext

@Nonnull
public F withContext(@Nonnull
                     java.lang.Object context)

Tells the Finder that results should be created with the given context. This method can be called multiple times; contexts are accumulated.

Specified by:

withContext in interface Finder<T>

Parameters:

context - the context

Returns:

the Finder

ofType

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

Tells the Finder that the specified type of results is expected.

Specified by:

ofType in interface Finder<T>

Type Parameters:

U - the static type

Parameters:

type - the dynamic type

Returns:

the Finder

sort

@Nonnull
public F 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<T>

Parameters:

criterion - the sort criterion

direction - the sort direction

Returns:

the Finder

sort

@Nonnull
public final F 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<T>

Parameters:

criterion - the sort criterion

Returns:

the Finder

results

@Nonnull
public java.util.List<T> results()

Performs the search and returns the found items.

Specified by:

results in interface Finder<T>

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<T>

Returns:

the count of found items

computeResults

@Nonnull
protected java.util.List<T> 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<T> computeNeededResults()

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

Returns:

the unprocessed results

getSource

@Nonnull
protected static <U> U getSource(@Nonnull
                                 java.lang.Class<? extends U> type,
                                 @Nonnull
                                 U other,
                                 @Nonnull
                                 java.lang.Object override)

A utility method used by the copy constructor (see general documentation). If the override object is strictly of the specified type, it is returned; otherwise the other object is returned.

Type Parameters:

U - the static type of the source

Parameters:

type - the dynamic type of the source

other - the other finder

override - the holder object

Returns:

the override or other