me.jaksa

Class FunctionalTransaction<T>

java.lang.Object

me.jaksa.FunctionalTransaction<T>

public class FunctionalTransaction<T>
extends Object

A lightweight transaction that returns a value. The FunctionalTransaction can have possible side effects and thus can have rollback and commit operations.

See Also:

VoidTransaction

Constructor Summary

Constructors

Constructor and Description
FunctionalTransaction(FunctionWithException<I,T> function, FunctionalTransaction<I> previous) Constructs a lightweight transaction chained to a previous one.
FunctionalTransaction(SupplierWithException<T> function) Constructs a lightweight transaction that can have a rollback and a commit.

Method Summary

Modifier and Type	Method and Description
<R> FunctionalTransaction<Pair<T,R>>	and(FunctionWithException<T,R> f) Creates another transaction and chains it to this one preserving the intermediate result.
FunctionalTransaction<T>	retry(int times) Specify the number of retires for the evaluation of this function.
<R> FunctionalTransaction<R>	then(FunctionWithException<T,R> function) Creates another transaction and chains it to this one.
FunctionalTransaction<T>	withCommit(java.util.function.Consumer<T> commit) Specify the commit for this function.
FunctionalTransaction<T>	withReset(java.util.function.Consumer<T> rollback) Alias for withRollback(Consumer)
FunctionalTransaction<T>	withRollback(java.util.function.Consumer<T> rollback) Specify the rollback for this function.
FunctionalTransaction<T>	withRollback(Runnable rollback) Specify the rollback for this function.
FunctionalTransaction<T>	withVerification(java.util.function.Function<T,Boolean> verification) Specify the verification for this function.

Methods inherited from class java.lang.Object

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

Constructor Detail

FunctionalTransaction

public FunctionalTransaction(SupplierWithException<T> function)

Constructs a lightweight transaction that can have a rollback and a commit.

Parameters:

function - the function to evaluate.

FunctionalTransaction

public FunctionalTransaction(FunctionWithException<I,T> function,
                             FunctionalTransaction<I> previous)

Constructs a lightweight transaction chained to a previous one.

Type Parameters:

I - the input type of the function

Parameters:

function - the function to evaluate.

previous - the FunctionalTransaction to attach to

Method Detail

withReset

public FunctionalTransaction<T> withReset(java.util.function.Consumer<T> rollback)

Alias for withRollback(Consumer)

Parameters:

rollback - the Runnable to perform in order to rollback any side effects of the transaction

Returns:

the transaction for chaining other invocations

withRollback

public FunctionalTransaction<T> withRollback(java.util.function.Consumer<T> rollback)

Specify the rollback for this function. Rollback will be performed after every unsuccessful attempt. The rollback should never throw an exception. The rollback will receive null if an exception has been thrown or the last value if the function failed during verification.

Parameters:

rollback - the Consumer to perform in order to rollback any side effects of the transaction

Returns:

the transaction for chaining other invocations

withRollback

public FunctionalTransaction<T> withRollback(Runnable rollback)

Specify the rollback for this function. Rollback will be performed after every unsuccessful attempt. The rollback should never throw an exception.

Parameters:

rollback - the Runnable to perform in order to rollback any side effects of the transaction

Returns:

the transaction for chaining other invocations

withCommit

public FunctionalTransaction<T> withCommit(java.util.function.Consumer<T> commit)

Specify the commit for this function. Commit will be performed only after a successful attempt. The commit should never throw an exception.

Parameters:

commit - the Consumer to perform in order to commit any side effects of this transaction

Returns:

the transaction for chaining other invocations

withVerification

public FunctionalTransaction<T> withVerification(java.util.function.Function<T,Boolean> verification)

Specify the verification for this function. Verification will be run to assess whether an attempt has been successful. If the function threw an Exception, verification is not necessary.

Parameters:

verification - - a Supplier that returns false if there has been an error

Returns:

the transaction for chaining other invocations

retry

public FunctionalTransaction<T> retry(int times)

Specify the number of retires for the evaluation of this function.

Parameters:

times - the number of times this transaction should be retried before giving up

Returns:

the transaction for chaining other invocations

then

public <R> FunctionalTransaction<R> then(FunctionWithException<T,R> function)

Creates another transaction and chains it to this one.

Type Parameters:

R - the return type of the new transaction

Parameters:

function - a function that takes the output of this transaction and returns a new value

Returns:

a new lightweight transaction chained to this one

and

public <R> FunctionalTransaction<Pair<T,R>> and(FunctionWithException<T,R> f)

Creates another transaction and chains it to this one preserving the intermediate result. The newly created transaction returns a Pair conatining the result of this transaction and the result of the function passed.

Type Parameters:

R - the return type of the new transaction

Parameters:

f - a function that takes the output of this transaction and returns a new value

Returns:

a new lightweight transaction chained to this one