Package com.google.common.collect
Class ForwardingIterator<T extends @Nullable Object>
- java.lang.Object
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- com.google.common.collect.ForwardingObject
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- com.google.common.collect.ForwardingIterator<T>
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- All Implemented Interfaces:
Iterator<T>
- Direct Known Subclasses:
ForwardingListIterator
@GwtCompatible public abstract class ForwardingIterator<T extends @Nullable Object> extends ForwardingObject implements Iterator<T>
An iterator which forwards all its method calls to another iterator. Subclasses should override one or more methods to modify the behavior of the backing iterator as desired per the decorator pattern.default
method warning: This class forwards calls to only somedefault
methods. Specifically, it forwards calls only for methods that existed beforedefault
methods were introduced. For newer methods, likeforEachRemaining
, it inherits their default implementations. When those implementations invoke methods, they invoke methods on theForwardingIterator
.- Since:
- 2.0
- Author:
- Kevin Bourrillion
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Constructor Summary
Constructors Modifier Constructor Description protected
ForwardingIterator()
Constructor for use by subclasses.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract Iterator<T>
delegate()
Returns the backing delegate instance that methods are forwarded to.boolean
hasNext()
Returnstrue
if the iteration has more elements.T
next()
Returns the next element in the iteration.void
remove()
Removes from the underlying collection the last element returned by this iterator (optional operation).-
Methods inherited from class com.google.common.collect.ForwardingObject
toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Iterator
forEachRemaining
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Constructor Detail
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ForwardingIterator
protected ForwardingIterator()
Constructor for use by subclasses.
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Method Detail
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delegate
protected abstract Iterator<T> delegate()
Description copied from class:ForwardingObject
Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such asForwardingSet.delegate()
. Concrete subclasses override this method to supply the instance being decorated.- Specified by:
delegate
in classForwardingObject
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hasNext
public boolean hasNext()
Description copied from interface:java.util.Iterator
Returnstrue
if the iteration has more elements. (In other words, returnstrue
ifIterator.next()
would return an element rather than throwing an exception.)
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next
@CanIgnoreReturnValue public T next()
Description copied from interface:java.util.Iterator
Returns the next element in the iteration.
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remove
public void remove()
Description copied from interface:java.util.Iterator
Removes from the underlying collection the last element returned by this iterator (optional operation). This method can be called only once per call toIterator.next()
.The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method, unless an overriding class has specified a concurrent modification policy.
The behavior of an iterator is unspecified if this method is called after a call to the
forEachRemaining
method.
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