org.dbflute.optional

クラス OptionalEntity<ENTITY>

java.lang.Object

org.dbflute.optional.BaseOptional<ENTITY>

org.dbflute.optional.OptionalEntity<ENTITY>

型パラメータ:

ENTITY - The type of entity.

すべての実装されたインタフェース:

OptionalThing<ENTITY>

public class OptionalEntity<ENTITY>
extends BaseOptional<ENTITY>

The entity as optional object, which has entity instance in it.
You can handle null value by this methods without direct null handling.

 // if the data always exists as your business rule
 memberBhv.selectEntity(cb -> {
     cb.setupSelect_MemberStatus();
     cb.query().setMemberId_Equal(1);
 }).alwaysPresent(member -> {
     // called if present, or exception
     ... = member.getMemberName();
 });

 // if it might be no data, ...
 memberBhv.selectEntity(cb -> cb.acceptPK(1)).ifPresent(member -> {
     // called if present
     ... = member.getMemberName();
 }).orElse(() -> {
     // called if not present
 });
 

導入されたバージョン:

1.0.5F (2014/05/05 Monday)

作成者:

jflute

フィールドのサマリー

フィールド

修飾子とタイプ	フィールドと説明
protected static OptionalEntity<Object>	EMPTY_INSTANCE
protected static OptionalThingExceptionThrower	NOWAY_THROWER

クラスから継承されたフィールド org.dbflute.optional.BaseOptional

_obj, _thrower, IF_PRESENT_AFTER_EMPTY, IF_PRESENT_AFTER_NONE_FIRE

コンストラクタのサマリー

コンストラクタ

コンストラクタと説明
OptionalEntity(ENTITY entity, OptionalThingExceptionThrower thrower)

メソッドのサマリー

修飾子とタイプ	メソッドと説明
void	alwaysPresent(OptionalThingConsumer<ENTITY> entityLambda) Handle the entity in the optional object or exception if not present.
protected void	assertEntityLambdaNotNull(Object entityLambda)
protected <ARG> OptionalEntity<ARG>	createOptionalFilteredObject(ARG obj)
protected <ARG> OptionalEntity<ARG>	createOptionalFlatMappedObject(ARG obj)
protected <ARG> OptionalEntity<ARG>	createOptionalMappedObject(ARG obj)
static <EMPTY> OptionalEntity<EMPTY>	empty()
OptionalEntity<ENTITY>	filter(OptionalThingPredicate<ENTITY> entityLambda) Filter the entity by the predicate.
<RESULT> OptionalThing<RESULT>	flatMap(OptionalThingFunction<? super ENTITY,OptionalThing<RESULT>> entityLambda) Apply the flat-mapping of entity to result object.
ENTITY	get() Get the entity or exception if null.
OptionalThingIfPresentAfter	ifPresent(OptionalThingConsumer<ENTITY> entityLambda) Handle the wrapped entity if it is present.
boolean	isPresent() Is the entity instance present?
<RESULT> OptionalEntity<RESULT>	map(OptionalThingFunction<? super ENTITY,? extends RESULT> entityLambda) Apply the mapping of entity to result object.
static <ENTITY> OptionalEntity<ENTITY>	of(ENTITY entity)
static <ENTITY> OptionalEntity<ENTITY>	ofNullable(ENTITY entity, OptionalThingExceptionThrower noArgLambda)
ENTITY	orElse(ENTITY other) Get the wrapped instance or returns the specified thing.
ENTITY	orElseGet(OptionalThingSupplier<ENTITY> noArgLambda) Get the thing or get from the supplier.
ENTITY	orElseNull() 非推奨です。 basically use ifPresent() or use orElse(null)
<CAUSE extends Throwable> ENTITY	orElseThrow(OptionalThingSupplier<? extends CAUSE> noArgLambda) Get the thing or throw the exception.
static <EMPTY> OptionalEntity<EMPTY>	relationEmpty(Object entity, String relation)
protected static void	throwNonSetupSelectRelationAccessException(Object entity, String relation)

クラスから継承されたメソッド org.dbflute.optional.BaseOptional

callbackAlwaysPresent, callbackFilter, callbackFlatMapping, callbackIfPresent, callbackMapping, directlyGet, directlyGetOrElse, directlyGetOrElseGet, directlyGetOrElseThrow, equals, exists, hashCode, toOptional, toString

クラスから継承されたメソッド java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

フィールドの詳細

EMPTY_INSTANCE

protected static final OptionalEntity<Object> EMPTY_INSTANCE

NOWAY_THROWER

protected static final OptionalThingExceptionThrower NOWAY_THROWER

コンストラクタの詳細

OptionalEntity

public OptionalEntity(ENTITY entity,
                      OptionalThingExceptionThrower thrower)

パラメータ:

entity - The wrapped instance of entity. (NullAllowed)

thrower - The exception thrower when illegal access. (NotNull)

メソッドの詳細

empty

public static <EMPTY> OptionalEntity<EMPTY> empty()

型パラメータ:

EMPTY - The type of empty optional entity.

戻り値:

The fixed instance as empty. (NotNull)

of

public static <ENTITY> OptionalEntity<ENTITY> of(ENTITY entity)

型パラメータ:

ENTITY - The type of entity wrapped in the optional entity.

パラメータ:

entity - The wrapped entity for the optional object. (NotNull)

戻り値:

The new-created instance as existing optional object. (NotNull)

ofNullable

public static <ENTITY> OptionalEntity<ENTITY> ofNullable(ENTITY entity,
                                                         OptionalThingExceptionThrower noArgLambda)

型パラメータ:

ENTITY - The type of entity for the optional type.

パラメータ:

entity - The wrapped instance or entity. (NullAllowed)

noArgLambda - The exception thrower when illegal access. (NotNull)

戻り値:

The new-created instance as existing or empty optional object. (NotNull)

relationEmpty

public static <EMPTY> OptionalEntity<EMPTY> relationEmpty(Object entity,
                                                          String relation)

型パラメータ:

EMPTY - The type of empty optional entity.

パラメータ:

entity - The base entity of the relation for exception message. (NotNull)

relation - The property name of the relation for exception message. (NotNull)

戻り値:

The new-created instance as existing or empty optional object. (NotNull)

throwNonSetupSelectRelationAccessException

protected static void throwNonSetupSelectRelationAccessException(Object entity,
                                                                 String relation)

ifPresent

public OptionalThingIfPresentAfter ifPresent(OptionalThingConsumer<ENTITY> entityLambda)

Handle the wrapped entity if it is present.
You should call this if null entity handling is unnecessary (do nothing if null).
If exception is preferred when null entity, use required().

 memberBhv.selectEntity(cb -> {
     cb.setupSelect_MemberWithdrawal();
     cb.query().setMemberId_Equal(1);
 }).ifPresent(member -> { // called if value exists, or not called
     ... = member.getMemberName();
     member.getMemberWithdrawal().ifPresent(withdrawal -> { // also relation
         ... = withdrawal.getWithdrawalDatetime();
     });
 }).orElse(() -> {
     // called if no value
 });
 

パラメータ:

entityLambda - The callback interface to consume the optional entity. (NotNull)

戻り値:

The handler of after process when if not present. (NotNull)

isPresent

public boolean isPresent()

Is the entity instance present? (existing?)

 OptionalEntity<Member> optMember = memberBhv.selectEntity(cb -> {
     cb.query()...;
 });
 if (optMember.isPresent()) { // true if the entity exists
     Member member = optMember.get();
 } else {
     ...
 }
 

戻り値:

The determination, true or false.

get

public ENTITY get()

Get the entity or exception if null.

 OptionalEntity<Member> optMember = memberBhv.selectEntity(cb -> {
     cb.setupSelect_MemberStatus();
     cb.query().setMemberId_Equal(1);
 });

 // if the data always exists as your business rule
 Member member = optMember.get();

 // if it might be no data, isPresent(), orElse(), ...
 if (optMember.isPresent()) {
     Member member = optMember.get();
 } else {
     ...
 }
 

戻り値:

The entity instance wrapped in this optional object. (NotNull)

例外:

EntityAlreadyDeletedException - When the entity instance wrapped in this optional object is null, which means entity has already been deleted (point is not found).

filter

public OptionalEntity<ENTITY> filter(OptionalThingPredicate<ENTITY> entityLambda)

Filter the entity by the predicate.

 memberBhv.selectEntity(cb -> cb.acceptPK(1)).filter(member -> {
     // called if value exists, not called if not present
     return member.getMemberId() % 2 == 0;
 }).ifPresent(member -> {
     ...
 });
 

パラメータ:

entityLambda - The callback to predicate whether the entity is remained. (NotNull)

戻り値:

The filtered optional entity, might be empty. (NotNull)

createOptionalFilteredObject

protected <ARG> OptionalEntity<ARG> createOptionalFilteredObject(ARG obj)

定義:

createOptionalFilteredObject クラス内 BaseOptional<ENTITY>

型パラメータ:

ARG - The type of value for optional thing.

パラメータ:

obj - The plain object for the optional thing. (NullAllowed: if null, return s empty optional)

戻り値:

The new-created instance of optional thing. (NotNull)

map

public <RESULT> OptionalEntity<RESULT> map(OptionalThingFunction<? super ENTITY,? extends RESULT> entityLambda)

Apply the mapping of entity to result object.

 memberBhv.selectEntity(cb -> cb.acceptPK(1)).map(member -> {
     // called if value exists, not called if not present
     return new MemberWebBean(member);
 }).alwaysPresent(member -> {
     ...
 });
 

型パラメータ:

RESULT - The type of mapping result.

パラメータ:

entityLambda - The callback interface to apply, null return allowed as empty. (NotNull)

戻り値:

The optional thing as mapped result. (NotNull, EmptyOptionalAllowed: if not present or callback returns null)

createOptionalMappedObject

protected <ARG> OptionalEntity<ARG> createOptionalMappedObject(ARG obj)

定義:

createOptionalMappedObject クラス内 BaseOptional<ENTITY>

型パラメータ:

ARG - The type of value for optional thing.

パラメータ:

obj - The plain object for the optional thing. (NullAllowed: if null, return s empty optional)

戻り値:

The new-created instance of optional thing. (NotNull)

flatMap

public <RESULT> OptionalThing<RESULT> flatMap(OptionalThingFunction<? super ENTITY,OptionalThing<RESULT>> entityLambda)

Apply the flat-mapping of entity to result object.

 memberBhv.selectEntity(cb -> cb.acceptPK(1)).flatMap(member -> {
     // called if value exists, not called if not present
     return member.getMemberWithdrawal();
 }).ifPresent(withdrawal -> {
     ...
 });
 

型パラメータ:

RESULT - The type of mapping result.

パラメータ:

entityLambda - The callback interface to apply, cannot return null. (NotNull)

戻り値:

The optional thing as mapped result. (NotNull, EmptyOptionalAllowed: when not present)

createOptionalFlatMappedObject

protected <ARG> OptionalEntity<ARG> createOptionalFlatMappedObject(ARG obj)

定義:

createOptionalFlatMappedObject クラス内 BaseOptional<ENTITY>

型パラメータ:

ARG - The type of value for optional thing.

パラメータ:

obj - The plain object for the optional thing. (NullAllowed: if null, return s empty optional)

戻り値:

The new-created instance of optional thing. (NotNull)

orElse

public ENTITY orElse(ENTITY other)

Get the wrapped instance or returns the specified thing.

パラメータ:

other - The object instance to be returned when the optional is empty. (NullAllowed)

戻り値:

The wrapped instance or specified other object. (NullAllowed:)

orElseGet

public ENTITY orElseGet(OptionalThingSupplier<ENTITY> noArgLambda)

Get the thing or get from the supplier.

パラメータ:

noArgLambda - The supplier of other instance if null. (NotNull)

戻り値:

The object instance wrapped in this optional thing or specified value. (NullAllowed: if null specified)

orElseThrow

public <CAUSE extends Throwable> ENTITY orElseThrow(OptionalThingSupplier<? extends CAUSE> noArgLambda)
                                             throws CAUSE extends Throwable

Get the thing or throw the exception.

型パラメータ:

CAUSE - The type of cause.

パラメータ:

noArgLambda - The supplier of exception if null. (NotNull)

戻り値:

The object instance wrapped in this optional object. (NotNull: if null, exception)

例外:

CAUSE - When the value is null.

CAUSE extends Throwable

alwaysPresent

public void alwaysPresent(OptionalThingConsumer<ENTITY> entityLambda)

Handle the entity in the optional object or exception if not present.

 memberBhv.selectEntity(cb -> {
     cb.setupSelect_MemberStatus();
     cb.query().setMemberId_Equal(1);
 }).alwaysPresent(member -> { // called if value exists, or exception
     ... = member.getMemberName();
     member.getMemberStatus().alwaysPresent(status -> { // also relation
         ... = status.getMemberStatusName();
     });
 });
 

パラメータ:

entityLambda - The callback interface to consume the optional value. (NotNull)

例外:

EntityAlreadyDeletedException - When the entity instance wrapped in this optional object is null, which means entity has already been deleted (point is not found).

orElseNull

public ENTITY orElseNull()

非推奨です。 basically use ifPresent() or use orElse(null)

Get the entity instance or null if not present.
basically use ifPresent() if might be not present, this is for emergency

戻り値:

The object instance wrapped in this optional object or null. (NullAllowed: if not present)

assertEntityLambdaNotNull

protected void assertEntityLambdaNotNull(Object entityLambda)