Package org.apache.cassandra.utils

Class AbstractGuavaIterator<T>

java.lang.Object
org.apache.cassandra.utils.AbstractGuavaIterator<T>
All Implemented Interfaces:
com.google.common.collect.PeekingIterator<T>, Iterator<T>
Direct Known Subclasses:
KeyRangeIterator, RangeIterator
@NotThreadSafe public abstract class AbstractGuavaIterator<T> extends 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.

  • Field Details

  • Constructor Details

    • AbstractGuavaIterator

      protected AbstractGuavaIterator()
      Constructor for use by subclasses.

  • Method Details

    • 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:
      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 Iterator<T>

    • tryToComputeNext

      protected boolean tryToComputeNext()

    • next

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

    • remove

      public void remove()
      Specified by:
      remove in interface 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>