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package java.util; |
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/** |
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* This class provides a skeletal implementation of the {@code List} |
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* This class provides a skeletal implementation of the {@link List} |
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* interface to minimize the effort required to implement this interface |
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* backed by a "random access" data store (such as an array). For sequential |
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* access data (such as a linked list), {@code AbstractSequentialList} should |
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* access data (such as a linked list), {@link AbstractSequentialList} should |
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* be used in preference to this class. |
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* |
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* <p>To implement an unmodifiable list, the programmer needs only to extend this |
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* class and provide implementations for the {@code get(int index)} and |
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* {@code size()} methods. |
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* <p>To implement an unmodifiable list, the programmer needs only to extend |
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* this class and provide implementations for the {@link #get(int)} and |
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* {@link List#size() size()} methods. |
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* |
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* <p>To implement a modifiable list, the programmer must additionally override |
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* the {@code set(int index, Object element)} method (which otherwise throws |
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* an {@code UnsupportedOperationException}. If the list is variable-size |
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* the programmer must additionally override the {@code add(int index, Object |
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* element)} and {@code remove(int index)} methods. |
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* <p>To implement a modifiable list, the programmer must additionally |
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* override the {@link #set(int, Object) set(int, E)} method (which otherwise |
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* throws an {@code UnsupportedOperationException}). If the list is |
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* variable-size the programmer must additionally override the |
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* {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods. |
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* |
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* <p>The programmer should generally provide a void (no argument) and collection |
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* constructor, as per the recommendation in the {@code Collection} interface |
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* constructor, as per the recommendation in the {@link Collection} interface |
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* specification. |
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* |
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* <p>Unlike the other abstract collection implementations, the programmer does |
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* <i>not</i> have to provide an iterator implementation; the iterator and |
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* list iterator are implemented by this class, on top of the "random access" |
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* methods: {@code get(int index)}, {@code set(int index, E element)}, |
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* {@code add(int index, E element)} and {@code remove(int index)}. |
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* methods: |
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* {@link #get(int)}, |
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* {@link #set(int, Object) set(int, E)}, |
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* {@link #add(int, Object) add(int, E)} and |
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* {@link #remove(int)}. |
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* |
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* <p>The documentation for each non-abstract methods in this class describes its |
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* <p>The documentation for each non-abstract method in this class describes its |
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* implementation in detail. Each of these methods may be overridden if the |
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* collection being implemented admits a more efficient implementation. |
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* |
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* @author Josh Bloch |
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* @author Neal Gafter |
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* @version %I%, %G% |
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* @see Collection |
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* @see List |
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* @see AbstractSequentialList |
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* @see AbstractCollection |
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* @since 1.2 |
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*/ |
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* <p>This implementation calls {@code add(size(), e)}. |
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* |
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* <p>Note that this implementation throws an |
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* {@code UnsupportedOperationException} unless {@code add(int, Object)} |
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* is overridden. |
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* {@code UnsupportedOperationException} unless |
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* {@link #add(int, Object) add(int, E)} is overridden. |
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* |
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* @param e element to be appended to this list |
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* @return {@code true} (as specified by {@link Collection#add}) |
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation gets an iterator over the specified collection and |
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* iterates over it, inserting the elements obtained from the iterator |
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* into this list at the appropriate position, one at a time, using |
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* {@code add(int, Object)}. Many implementations will override this |
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* method for efficiency. |
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* <p>This implementation gets an iterator over the specified collection |
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* and iterates over it, inserting the elements obtained from the |
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* iterator into this list at the appropriate position, one at a time, |
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* using {@code add(int, E)}. |
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* Many implementations will override this method for efficiency. |
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* |
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* <p>Note that this implementation throws an |
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* {@code UnsupportedOperationException} unless {@code add(int, Object)} |
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* is overridden. |
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* {@code UnsupportedOperationException} unless |
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* {@link #add(int, Object) add(int, E)} is overridden. |
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* |
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* @throws UnsupportedOperationException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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// Iterators |
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/** |
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* Returns an iterator over the elements in this list in proper |
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* sequence. <p> |
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* Returns an iterator over the elements in this list in proper sequence. |
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* |
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* This implementation returns a straightforward implementation of the |
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* <p>This implementation returns a straightforward implementation of the |
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* iterator interface, relying on the backing list's {@code size()}, |
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* {@code get(int)}, and {@code remove(int)} methods.<p> |
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* {@code get(int)}, and {@code remove(int)} methods. |
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* |
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* Note that the iterator returned by this method will throw an |
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* <p>Note that the iterator returned by this method will throw an |
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* {@code UnsupportedOperationException} in response to its |
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* {@code remove} method unless the list's {@code remove(int)} method is |
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* overridden.<p> |
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* overridden. |
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* |
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* This implementation can be made to throw runtime exceptions in the face |
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* of concurrent modification, as described in the specification for the |
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* (protected) {@code modCount} field. |
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* <p>This implementation can be made to throw runtime exceptions in the |
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* face of concurrent modification, as described in the specification |
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* for the (protected) {@code modCount} field. |
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* |
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* @return an iterator over the elements in this list in proper sequence |
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* |
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* {@code ListIterator} interface that extends the implementation of the |
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* {@code Iterator} interface returned by the {@code iterator()} method. |
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* The {@code ListIterator} implementation relies on the backing list's |
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* {@code get(int)}, {@code set(int, Object)}, {@code add(int, Object)} |
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* {@code get(int)}, {@code set(int, E)}, {@code add(int, E)} |
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* and {@code remove(int)} methods. |
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* |
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* <p>Note that the list iterator returned by this implementation will |
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* throw an {@code UnsupportedOperationException} in response to its |
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* {@code remove}, {@code set} and {@code add} methods unless the |
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* list's {@code remove(int)}, {@code set(int, Object)}, and |
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* {@code add(int, Object)} methods are overridden. |
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* list's {@code remove(int)}, {@code set(int, E)}, and |
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* {@code add(int, E)} methods are overridden. |
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* |
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* <p>This implementation can be made to throw runtime exceptions in the |
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* face of concurrent modification, as described in the specification for |
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* If this list implements {@code RandomAccess} the returned list will |
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* be an instance of the subclass that implements {@code RandomAccess}. |
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* |
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* <p>The subclass's {@code set(int, Object)}, {@code get(int)}, |
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* {@code add(int, Object)}, {@code remove(int)}, {@code addAll(int, |
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* <p>The subclass's {@code set(int, E)}, {@code get(int)}, |
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* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int, |
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* Collection)} and {@code removeRange(int, int)} methods all |
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* delegate to the corresponding methods on the backing abstract list, |
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* after bounds-checking the index and adjusting for the offset. The |
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* {@code ConcurrentModificationException} if it is not. |
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* |
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* @throws IndexOutOfBoundsException endpoint index value out of range |
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* {@code (fromIndex < 0 || toIndex > size)} |
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* {@code (fromIndex < 0 || toIndex > size)} |
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* @throws IllegalArgumentException if the endpoint indices are out of order |
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* {@code (fromIndex > toIndex)} |
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* {@code (fromIndex > toIndex)} |
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*/ |
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public List<E> subList(int fromIndex, int toIndex) { |
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return (this instanceof RandomAccess ? |
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* the two lists are <i>equal</i>. (Two elements {@code e1} and |
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* {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null : |
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* e1.equals(e2))}.) In other words, two lists are defined to be |
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* equal if they contain the same elements in the same order.<p> |
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* equal if they contain the same elements in the same order. |
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* |
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* This implementation first checks if the specified object is this |
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* <p>This implementation first checks if the specified object is this |
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* list. If so, it returns {@code true}; if not, it checks if the |
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* specified object is a list. If not, it returns {@code false}; if so, |
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* it iterates over both lists, comparing corresponding pairs of elements. |
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} |
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/** |
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* Returns the hash code value for this list. <p> |
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* Returns the hash code value for this list. |
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* |
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< |
* This implementation uses exactly the code that is used to define the |
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> |
* <p>This implementation uses exactly the code that is used to define the |
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* list hash function in the documentation for the {@link List#hashCode} |
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* method. |
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* |
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* Shifts any succeeding elements to the left (reduces their index). |
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* This call shortens the ArrayList by {@code (toIndex - fromIndex)} |
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* elements. (If {@code toIndex==fromIndex}, this operation has no |
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< |
* effect.)<p> |
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> |
* effect.) |
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* |
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< |
* This method is called by the {@code clear} operation on this list |
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> |
* <p>This method is called by the {@code clear} operation on this list |
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* and its subLists. Overriding this method to take advantage of |
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* the internals of the list implementation can <i>substantially</i> |
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* improve the performance of the {@code clear} operation on this list |
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< |
* and its subLists.<p> |
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> |
* and its subLists. |
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* |
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< |
* This implementation gets a list iterator positioned before |
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> |
* <p>This implementation gets a list iterator positioned before |
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* {@code fromIndex}, and repeatedly calls {@code ListIterator.next} |
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* followed by {@code ListIterator.remove} until the entire range has |
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* been removed. <b>Note: if {@code ListIterator.remove} requires linear |
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* The number of times this list has been <i>structurally modified</i>. |
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* Structural modifications are those that change the size of the |
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* list, or otherwise perturb it in such a fashion that iterations in |
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< |
* progress may yield incorrect results.<p> |
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> |
* progress may yield incorrect results. |
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* |
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< |
* This field is used by the iterator and list iterator implementation |
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> |
* <p>This field is used by the iterator and list iterator implementation |
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* returned by the {@code iterator} and {@code listIterator} methods. |
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* If the value of this field changes unexpectedly, the iterator (or list |
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* iterator) will throw a {@code ConcurrentModificationException} in |
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* response to the {@code next}, {@code remove}, {@code previous}, |
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* {@code set} or {@code add} operations. This provides |
| 577 |
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* <i>fail-fast</i> behavior, rather than non-deterministic behavior in |
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< |
* the face of concurrent modification during iteration.<p> |
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> |
* the face of concurrent modification during iteration. |
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* |
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< |
* <b>Use of this field by subclasses is optional.</b> If a subclass |
| 580 |
> |
* <p><b>Use of this field by subclasses is optional.</b> If a subclass |
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* wishes to provide fail-fast iterators (and list iterators), then it |
| 582 |
< |
* merely has to increment this field in its {@code add(int, Object)} and |
| 582 |
> |
* merely has to increment this field in its {@code add(int, E)} and |
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* {@code remove(int)} methods (and any other methods that it overrides |
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* that result in structural modifications to the list). A single call to |
| 585 |
< |
* {@code add(int, Object)} or {@code remove(int)} must add no more than |
| 585 |
> |
* {@code add(int, E)} or {@code remove(int)} must add no more than |
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* one to this field, or the iterators (and list iterators) will throw |
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* bogus {@code ConcurrentModificationExceptions}. If an implementation |
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* does not wish to provide fail-fast iterators, this field may be |
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fromIndex, toIndex); |
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} |
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} |
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– |
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