Package org.elasticsearch.common.util

Class LazyInitializable<T,​E extends java.lang.Exception>

  • public final class LazyInitializable<T,​E extends java.lang.Exception>
extends java.lang.Object
    Encapsulates a CheckedSupplier which is lazily invoked once on the first call to #getOrCompute(). The value which the supplier returns is memorized and will be served until #reset() is called. Each value returned by #getOrCompute(), newly minted or cached, will be passed to the onGet Consumer. On #reset() the value will be passed to the onReset Consumer and the next #getOrCompute() will regenerate the value.

    • Method Summary

      Modifier and Type Method Description
      T getOrCompute()
      Returns a value that was created by supplier.
      void reset()
      Clears the value, if it has been previously created by calling #getOrCompute().

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • LazyInitializable

        public LazyInitializable​(CheckedSupplier<T,​E> supplier)
        Creates the simple LazyInitializable instance.
        Parameters:
        supplier - The CheckedSupplier to generate values which will be served on #getOrCompute() invocations.

      • LazyInitializable

        public LazyInitializable​(CheckedSupplier<T,​E> supplier,
                         java.util.function.Consumer<T> onGet,
                         java.util.function.Consumer<T> onReset)
        Creates the complete LazyInitializable instance.
        Parameters:
        supplier - The CheckedSupplier to generate values which will be served on #getOrCompute() invocations.
        onGet - A Consumer which is called on each value, newly forged or stale, that is returned by #getOrCompute()
        onReset - A Consumer which is invoked on the value that will be erased when calling #reset()

    • Method Detail

      • getOrCompute

        public T getOrCompute()
               throws E extends java.lang.Exception
        Returns a value that was created by supplier. The value might have been previously created, if not it will be created now, thread safe of course.
        Throws:
        E extends java.lang.Exception

      • reset

        public void reset()
        Clears the value, if it has been previously created by calling #getOrCompute(). The onReset will be called on this value. The next call to #getOrCompute() will recreate the value.