Package org.apache.cassandra.utils

Class AbstractGuavaIterator<T>

  • All Implemented Interfaces:
    com.google.common.collect.PeekingIterator<T>, java.util.Iterator<T>
    Direct Known Subclasses:
    KeyRangeIterator, RangeIterator
    @NotThreadSafe
public abstract class AbstractGuavaIterator<T>
extends java.lang.Object
implements com.google.common.collect.PeekingIterator<T>
    This is fork of the Guava AbstractIterator, the only difference is that the next variable is now protected so that the KeyRangeIterator.skipTo method can avoid early state changed.

    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected AbstractGuavaIterator()
      Constructor for use by subclasses.

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      protected abstract T computeNext()
      Returns the next element.
      protected T endOfData()
      Implementations of computeNext() must invoke this method when there are no elements left in the iteration.
      boolean hasNext()  
      T next()  
      T peek()
      Returns the next element in the iteration without advancing the iteration, according to the contract of PeekingIterator.peek().
      void remove()  
      protected boolean tryToComputeNext()  

      • Methods inherited from class java.lang.Object

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

      • Methods inherited from interface java.util.Iterator

        forEachRemaining

    • Constructor Detail

      • AbstractGuavaIterator

        protected AbstractGuavaIterator()
        Constructor for use by subclasses.

    • Method Detail

      • computeNext

        protected abstract T computeNext()
        Returns the next element. Note: the implementation must call endOfData() when there are no elements left in the iteration. Failure to do so could result in an infinite loop.

        The initial invocation of hasNext() or next() calls this method, as does the first invocation of hasNext or next following each successful call to next. Once the implementation either invokes endOfData or throws an exception, computeNext is guaranteed to never be called again.

        If this method throws an exception, it will propagate outward to the hasNext or next invocation that invoked this method. Any further attempts to use the iterator will result in an IllegalStateException.

        The implementation of this method may not invoke the hasNext, next, or peek() methods on this instance; if it does, an IllegalStateException will result.

        Returns:
        the next element if there was one. If endOfData was called during execution, the return value will be ignored.
        Throws:
        java.lang.RuntimeException - if any unrecoverable error happens. This exception will propagate outward to the hasNext(), next(), or peek() invocation that invoked this method. Any further attempts to use the iterator will result in an IllegalStateException.

      • endOfData

        protected final T endOfData()
        Implementations of computeNext() must invoke this method when there are no elements left in the iteration.
        Returns:
        null; a convenience so your computeNext implementation can use the simple statement return endOfData();

      • hasNext

        public final boolean hasNext()
        Specified by:
        hasNext in interface java.util.Iterator<T>

      • tryToComputeNext

        protected boolean tryToComputeNext()

      • next

        public final T next()
        Specified by:
        next in interface java.util.Iterator<T>
        Specified by:
        next in interface com.google.common.collect.PeekingIterator<T>

      • remove

        public void remove()
        Specified by:
        remove in interface java.util.Iterator<T>
        Specified by:
        remove in interface com.google.common.collect.PeekingIterator<T>

      • peek

        public final T peek()
        Returns the next element in the iteration without advancing the iteration, according to the contract of PeekingIterator.peek().

        Implementations of AbstractIterator that wish to expose this functionality should implement PeekingIterator.

        Specified by:
        peek in interface com.google.common.collect.PeekingIterator<T>