Package org.dataloader

Class Try<V>

  • @PublicApi
public class Try<V>
extends java.lang.Object
    Try is class that allows you to hold the result of computation or the throwable it produced. This class is useful in BatchLoaders so you can mix a batch of calls where some the calls succeeded and some of them failed. You would make your batch loader declaration like : 
     BatchLoader<K,Try<V> batchLoader = new BatchLoader() { ... }
    DataLoader understands the use of Try and will take the exceptional path and complete the value promise with that exception value.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static <V> Try<V> alwaysFailed()
      This returns a Try that has always failed with a consistent exception.
      static <V> Try<V> failed​(java.lang.Throwable throwable)
      Creates a Try that has failed with the provided throwable
      <U> Try<U> flatMap​(java.util.function.Function<? super V,​Try<U>> mapper)
      Flats maps the Try into another Try type
      V get()  
      java.lang.Throwable getThrowable()  
      boolean isFailure()  
      boolean isSuccess()  
      <U> Try<U> map​(java.util.function.Function<? super V,​U> mapper)
      Maps the Try into another Try with a different type
      V orElse​(V other)
      Returns the successful value of the Try or other if it failed
      V orElseGet​(java.util.function.Supplier<V> otherSupplier)
      Returns the successful value of the Try or the supplied other if it failed
      Try<V> recover​(java.util.function.Function<java.lang.Throwable,​V> recoverFunction)
      Called the recover function of the Try failed otherwise returns this if it was successful.
      void reThrow()
      Rethrows the underlying throwable inside the unsuccessful Try
      static <V> Try<V> succeeded​(V value)
      Creates a Try that has succeeded with the provided value
      java.util.Optional<V> toOptional()
      Converts the Try into an Optional where unsuccessful tries are empty
      java.lang.String toString()  
      static <V> Try<V> tryCall​(java.util.concurrent.Callable<V> callable)
      Calls the callable and if it returns a value, the Try is successful with that value or if throws and exception the Try captures that
      static <V> java.util.concurrent.CompletableFuture<Try<V>> tryFuture​(java.util.concurrent.CompletionStage<V> completionStage)
      Creates a CompletableFuture that, when it completes, will capture into a Try whether the given completionStage was successful or not
      static <V> java.util.concurrent.CompletionStage<Try<V>> tryStage​(java.util.concurrent.CompletionStage<V> completionStage)
      Creates a CompletionStage that, when it completes, will capture into a Try whether the given completionStage was successful or not

      • Methods inherited from class java.lang.Object

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

    • Method Detail

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • succeeded

        public static <V> Try<V> succeeded​(V value)
        Creates a Try that has succeeded with the provided value
        Type Parameters:
        V - the value type
        Parameters:
        value - the successful value
        Returns:
        a successful Try

      • failed

        public static <V> Try<V> failed​(java.lang.Throwable throwable)
        Creates a Try that has failed with the provided throwable
        Type Parameters:
        V - the value type
        Parameters:
        throwable - the failed throwable
        Returns:
        a failed Try

      • alwaysFailed

        public static <V> Try<V> alwaysFailed()
        This returns a Try that has always failed with a consistent exception. Use this when you don't care about the exception but only that the Try failed.
        Type Parameters:
        V - the type of value
        Returns:
        a Try that has failed

      • tryCall

        public static <V> Try<V> tryCall​(java.util.concurrent.Callable<V> callable)
        Calls the callable and if it returns a value, the Try is successful with that value or if throws and exception the Try captures that
        Type Parameters:
        V - the value type
        Parameters:
        callable - the code to call
        Returns:
        a Try which is the result of the call

      • tryStage

        public static <V> java.util.concurrent.CompletionStage<Try<V>> tryStage​(java.util.concurrent.CompletionStage<V> completionStage)
        Creates a CompletionStage that, when it completes, will capture into a Try whether the given completionStage was successful or not
        Type Parameters:
        V - the value type
        Parameters:
        completionStage - the completion stage that will complete
        Returns:
        a CompletionStage Try which is the result of the call

      • tryFuture

        public static <V> java.util.concurrent.CompletableFuture<Try<V>> tryFuture​(java.util.concurrent.CompletionStage<V> completionStage)
        Creates a CompletableFuture that, when it completes, will capture into a Try whether the given completionStage was successful or not
        Type Parameters:
        V - the value type
        Parameters:
        completionStage - the completion stage that will complete
        Returns:
        a CompletableFuture Try which is the result of the call

      • get

        public V get()
        Returns:
        the successful value of this try
        Throws:
        java.lang.UnsupportedOperationException - if the Try is in fact in the unsuccessful state

      • getThrowable

        public java.lang.Throwable getThrowable()
        Returns:
        the failed throwable of this try
        Throws:
        java.lang.UnsupportedOperationException - if the Try is in fact in the successful state

      • isSuccess

        public boolean isSuccess()
        Returns:
        true if this Try succeeded and therefore has a value

      • isFailure

        public boolean isFailure()
        Returns:
        true if this Try failed and therefore has a throwable

      • map

        public <U> Try<U> map​(java.util.function.Function<? super V,​U> mapper)
        Maps the Try into another Try with a different type
        Type Parameters:
        U - the target type
        Parameters:
        mapper - the function to map the current Try to a new Try
        Returns:
        the mapped Try

      • flatMap

        public <U> Try<U> flatMap​(java.util.function.Function<? super V,​Try<U>> mapper)
        Flats maps the Try into another Try type
        Type Parameters:
        U - the target type
        Parameters:
        mapper - the flat map function
        Returns:
        a new Try

      • toOptional

        public java.util.Optional<V> toOptional()
        Converts the Try into an Optional where unsuccessful tries are empty
        Returns:
        a new optional

      • orElse

        public V orElse​(V other)
        Returns the successful value of the Try or other if it failed
        Parameters:
        other - the other value if the Try failed
        Returns:
        the value of the Try or an alternative

      • orElseGet

        public V orElseGet​(java.util.function.Supplier<V> otherSupplier)
        Returns the successful value of the Try or the supplied other if it failed
        Parameters:
        otherSupplier - the other value supplied if the Try failed
        Returns:
        the value of the Try or an alternative

      • reThrow

        public void reThrow()
             throws java.lang.Throwable
        Rethrows the underlying throwable inside the unsuccessful Try
        Throws:
        java.lang.Throwable - if the Try was in fact throwable
        java.lang.UnsupportedOperationException - if the try was in fact a successful Try

      • recover

        public Try<V> recover​(java.util.function.Function<java.lang.Throwable,​V> recoverFunction)
        Called the recover function of the Try failed otherwise returns this if it was successful.
        Parameters:
        recoverFunction - the function to recover from a throwable into a new value
        Returns:
        a Try of the same type