945 lines
33 KiB
Java
945 lines
33 KiB
Java
/*
|
|
* Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation. Oracle designates this
|
|
* particular file as subject to the "Classpath" exception as provided
|
|
* by Oracle in the LICENSE file that accompanied this code.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
package java.util;
|
|
|
|
import java.util.function.Consumer;
|
|
|
|
/**
|
|
* This class provides a skeletal implementation of the {@link List}
|
|
* interface to minimize the effort required to implement this interface
|
|
* backed by a "random access" data store (such as an array). For sequential
|
|
* access data (such as a linked list), {@link AbstractSequentialList} should
|
|
* be used in preference to this class.
|
|
*
|
|
* <p>To implement an unmodifiable list, the programmer needs only to extend
|
|
* this class and provide implementations for the {@link #get(int)} and
|
|
* {@link List#size() size()} methods.
|
|
*
|
|
* <p>To implement a modifiable list, the programmer must additionally
|
|
* override the {@link #set(int, Object) set(int, E)} method (which otherwise
|
|
* throws an {@code UnsupportedOperationException}). If the list is
|
|
* variable-size the programmer must additionally override the
|
|
* {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods.
|
|
*
|
|
* <p>The programmer should generally provide a void (no argument) and collection
|
|
* constructor, as per the recommendation in the {@link Collection} interface
|
|
* specification.
|
|
*
|
|
* <p>Unlike the other abstract collection implementations, the programmer does
|
|
* <i>not</i> have to provide an iterator implementation; the iterator and
|
|
* list iterator are implemented by this class, on top of the "random access"
|
|
* methods:
|
|
* {@link #get(int)},
|
|
* {@link #set(int, Object) set(int, E)},
|
|
* {@link #add(int, Object) add(int, E)} and
|
|
* {@link #remove(int)}.
|
|
*
|
|
* <p>The documentation for each non-abstract method in this class describes its
|
|
* implementation in detail. Each of these methods may be overridden if the
|
|
* collection being implemented admits a more efficient implementation.
|
|
*
|
|
* <p>This class is a member of the
|
|
* <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
|
|
* Java Collections Framework</a>.
|
|
*
|
|
* @param <E> the type of elements in this list
|
|
*
|
|
* @author Josh Bloch
|
|
* @author Neal Gafter
|
|
* @since 1.2
|
|
*/
|
|
|
|
public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> {
|
|
/**
|
|
* Sole constructor. (For invocation by subclass constructors, typically
|
|
* implicit.)
|
|
*/
|
|
protected AbstractList() {
|
|
}
|
|
|
|
/**
|
|
* Appends the specified element to the end of this list (optional
|
|
* operation).
|
|
*
|
|
* <p>Lists that support this operation may place limitations on what
|
|
* elements may be added to this list. In particular, some
|
|
* lists will refuse to add null elements, and others will impose
|
|
* restrictions on the type of elements that may be added. List
|
|
* classes should clearly specify in their documentation any restrictions
|
|
* on what elements may be added.
|
|
*
|
|
* @implSpec
|
|
* This implementation calls {@code add(size(), e)}.
|
|
*
|
|
* <p>Note that this implementation throws an
|
|
* {@code UnsupportedOperationException} unless
|
|
* {@link #add(int, Object) add(int, E)} is overridden.
|
|
*
|
|
* @param e element to be appended to this list
|
|
* @return {@code true} (as specified by {@link Collection#add})
|
|
* @throws UnsupportedOperationException if the {@code add} operation
|
|
* is not supported by this list
|
|
* @throws ClassCastException if the class of the specified element
|
|
* prevents it from being added to this list
|
|
* @throws NullPointerException if the specified element is null and this
|
|
* list does not permit null elements
|
|
* @throws IllegalArgumentException if some property of this element
|
|
* prevents it from being added to this list
|
|
*/
|
|
public boolean add(E e) {
|
|
add(size(), e);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public abstract E get(int index);
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation always throws an
|
|
* {@code UnsupportedOperationException}.
|
|
*
|
|
* @throws UnsupportedOperationException {@inheritDoc}
|
|
* @throws ClassCastException {@inheritDoc}
|
|
* @throws NullPointerException {@inheritDoc}
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public E set(int index, E element) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation always throws an
|
|
* {@code UnsupportedOperationException}.
|
|
*
|
|
* @throws UnsupportedOperationException {@inheritDoc}
|
|
* @throws ClassCastException {@inheritDoc}
|
|
* @throws NullPointerException {@inheritDoc}
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public void add(int index, E element) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation always throws an
|
|
* {@code UnsupportedOperationException}.
|
|
*
|
|
* @throws UnsupportedOperationException {@inheritDoc}
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public E remove(int index) {
|
|
throw new UnsupportedOperationException();
|
|
}
|
|
|
|
|
|
// Search Operations
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation first gets a list iterator (with
|
|
* {@code listIterator()}). Then, it iterates over the list until the
|
|
* specified element is found or the end of the list is reached.
|
|
*
|
|
* @throws ClassCastException {@inheritDoc}
|
|
* @throws NullPointerException {@inheritDoc}
|
|
*/
|
|
public int indexOf(Object o) {
|
|
ListIterator<E> it = listIterator();
|
|
if (o==null) {
|
|
while (it.hasNext())
|
|
if (it.next()==null)
|
|
return it.previousIndex();
|
|
} else {
|
|
while (it.hasNext())
|
|
if (o.equals(it.next()))
|
|
return it.previousIndex();
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation first gets a list iterator that points to the end
|
|
* of the list (with {@code listIterator(size())}). Then, it iterates
|
|
* backwards over the list until the specified element is found, or the
|
|
* beginning of the list is reached.
|
|
*
|
|
* @throws ClassCastException {@inheritDoc}
|
|
* @throws NullPointerException {@inheritDoc}
|
|
*/
|
|
public int lastIndexOf(Object o) {
|
|
ListIterator<E> it = listIterator(size());
|
|
if (o==null) {
|
|
while (it.hasPrevious())
|
|
if (it.previous()==null)
|
|
return it.nextIndex();
|
|
} else {
|
|
while (it.hasPrevious())
|
|
if (o.equals(it.previous()))
|
|
return it.nextIndex();
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
|
|
// Bulk Operations
|
|
|
|
/**
|
|
* Removes all of the elements from this list (optional operation).
|
|
* The list will be empty after this call returns.
|
|
*
|
|
* @implSpec
|
|
* This implementation calls {@code removeRange(0, size())}.
|
|
*
|
|
* <p>Note that this implementation throws an
|
|
* {@code UnsupportedOperationException} unless {@code remove(int
|
|
* index)} or {@code removeRange(int fromIndex, int toIndex)} is
|
|
* overridden.
|
|
*
|
|
* @throws UnsupportedOperationException if the {@code clear} operation
|
|
* is not supported by this list
|
|
*/
|
|
public void clear() {
|
|
removeRange(0, size());
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation gets an iterator over the specified collection
|
|
* and iterates over it, inserting the elements obtained from the
|
|
* iterator into this list at the appropriate position, one at a time,
|
|
* using {@code add(int, E)}.
|
|
* Many implementations will override this method for efficiency.
|
|
*
|
|
* <p>Note that this implementation throws an
|
|
* {@code UnsupportedOperationException} unless
|
|
* {@link #add(int, Object) add(int, E)} is overridden.
|
|
*
|
|
* @throws UnsupportedOperationException {@inheritDoc}
|
|
* @throws ClassCastException {@inheritDoc}
|
|
* @throws NullPointerException {@inheritDoc}
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public boolean addAll(int index, Collection<? extends E> c) {
|
|
rangeCheckForAdd(index);
|
|
boolean modified = false;
|
|
for (E e : c) {
|
|
add(index++, e);
|
|
modified = true;
|
|
}
|
|
return modified;
|
|
}
|
|
|
|
|
|
// Iterators
|
|
|
|
/**
|
|
* Returns an iterator over the elements in this list in proper sequence.
|
|
*
|
|
* @implSpec
|
|
* This implementation returns a straightforward implementation of the
|
|
* iterator interface, relying on the backing list's {@code size()},
|
|
* {@code get(int)}, and {@code remove(int)} methods.
|
|
*
|
|
* <p>Note that the iterator returned by this method will throw an
|
|
* {@link UnsupportedOperationException} in response to its
|
|
* {@code remove} method unless the list's {@code remove(int)} method is
|
|
* overridden.
|
|
*
|
|
* <p>This implementation can be made to throw runtime exceptions in the
|
|
* face of concurrent modification, as described in the specification
|
|
* for the (protected) {@link #modCount} field.
|
|
*
|
|
* @return an iterator over the elements in this list in proper sequence
|
|
*/
|
|
public Iterator<E> iterator() {
|
|
return new Itr();
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation returns {@code listIterator(0)}.
|
|
*
|
|
* @see #listIterator(int)
|
|
*/
|
|
public ListIterator<E> listIterator() {
|
|
return listIterator(0);
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation returns a straightforward implementation of the
|
|
* {@code ListIterator} interface that extends the implementation of the
|
|
* {@code Iterator} interface returned by the {@code iterator()} method.
|
|
* The {@code ListIterator} implementation relies on the backing list's
|
|
* {@code get(int)}, {@code set(int, E)}, {@code add(int, E)}
|
|
* and {@code remove(int)} methods.
|
|
*
|
|
* <p>Note that the list iterator returned by this implementation will
|
|
* throw an {@link UnsupportedOperationException} in response to its
|
|
* {@code remove}, {@code set} and {@code add} methods unless the
|
|
* list's {@code remove(int)}, {@code set(int, E)}, and
|
|
* {@code add(int, E)} methods are overridden.
|
|
*
|
|
* <p>This implementation can be made to throw runtime exceptions in the
|
|
* face of concurrent modification, as described in the specification for
|
|
* the (protected) {@link #modCount} field.
|
|
*
|
|
* @throws IndexOutOfBoundsException {@inheritDoc}
|
|
*/
|
|
public ListIterator<E> listIterator(final int index) {
|
|
rangeCheckForAdd(index);
|
|
|
|
return new ListItr(index);
|
|
}
|
|
|
|
private class Itr implements Iterator<E> {
|
|
/**
|
|
* Index of element to be returned by subsequent call to next.
|
|
*/
|
|
int cursor = 0;
|
|
|
|
/**
|
|
* Index of element returned by most recent call to next or
|
|
* previous. Reset to -1 if this element is deleted by a call
|
|
* to remove.
|
|
*/
|
|
int lastRet = -1;
|
|
|
|
/**
|
|
* The modCount value that the iterator believes that the backing
|
|
* List should have. If this expectation is violated, the iterator
|
|
* has detected concurrent modification.
|
|
*/
|
|
int expectedModCount = modCount;
|
|
|
|
public boolean hasNext() {
|
|
return cursor != size();
|
|
}
|
|
|
|
public E next() {
|
|
checkForComodification();
|
|
try {
|
|
int i = cursor;
|
|
E next = get(i);
|
|
lastRet = i;
|
|
cursor = i + 1;
|
|
return next;
|
|
} catch (IndexOutOfBoundsException e) {
|
|
checkForComodification();
|
|
throw new NoSuchElementException(e);
|
|
}
|
|
}
|
|
|
|
public void remove() {
|
|
if (lastRet < 0)
|
|
throw new IllegalStateException();
|
|
checkForComodification();
|
|
|
|
try {
|
|
AbstractList.this.remove(lastRet);
|
|
if (lastRet < cursor)
|
|
cursor--;
|
|
lastRet = -1;
|
|
expectedModCount = modCount;
|
|
} catch (IndexOutOfBoundsException e) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
|
|
final void checkForComodification() {
|
|
if (modCount != expectedModCount)
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
|
|
private class ListItr extends Itr implements ListIterator<E> {
|
|
ListItr(int index) {
|
|
cursor = index;
|
|
}
|
|
|
|
public boolean hasPrevious() {
|
|
return cursor != 0;
|
|
}
|
|
|
|
public E previous() {
|
|
checkForComodification();
|
|
try {
|
|
int i = cursor - 1;
|
|
E previous = get(i);
|
|
lastRet = cursor = i;
|
|
return previous;
|
|
} catch (IndexOutOfBoundsException e) {
|
|
checkForComodification();
|
|
throw new NoSuchElementException(e);
|
|
}
|
|
}
|
|
|
|
public int nextIndex() {
|
|
return cursor;
|
|
}
|
|
|
|
public int previousIndex() {
|
|
return cursor-1;
|
|
}
|
|
|
|
public void set(E e) {
|
|
if (lastRet < 0)
|
|
throw new IllegalStateException();
|
|
checkForComodification();
|
|
|
|
try {
|
|
AbstractList.this.set(lastRet, e);
|
|
expectedModCount = modCount;
|
|
} catch (IndexOutOfBoundsException ex) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
|
|
public void add(E e) {
|
|
checkForComodification();
|
|
|
|
try {
|
|
int i = cursor;
|
|
AbstractList.this.add(i, e);
|
|
lastRet = -1;
|
|
cursor = i + 1;
|
|
expectedModCount = modCount;
|
|
} catch (IndexOutOfBoundsException ex) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* {@inheritDoc}
|
|
*
|
|
* @implSpec
|
|
* This implementation returns a list that subclasses
|
|
* {@code AbstractList}. The subclass stores, in private fields, the
|
|
* size of the subList (which can change over its lifetime), and the
|
|
* expected {@code modCount} value of the backing list. There are two
|
|
* variants of the subclass, one of which implements {@code RandomAccess}.
|
|
* If this list implements {@code RandomAccess} the returned list will
|
|
* be an instance of the subclass that implements {@code RandomAccess}.
|
|
*
|
|
* <p>The subclass's {@code set(int, E)}, {@code get(int)},
|
|
* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int,
|
|
* Collection)} and {@code removeRange(int, int)} methods all
|
|
* delegate to the corresponding methods on the backing abstract list,
|
|
* after bounds-checking the index and adjusting for the offset. The
|
|
* {@code addAll(Collection c)} method merely returns {@code addAll(size,
|
|
* c)}.
|
|
*
|
|
* <p>The {@code listIterator(int)} method returns a "wrapper object"
|
|
* over a list iterator on the backing list, which is created with the
|
|
* corresponding method on the backing list. The {@code iterator} method
|
|
* merely returns {@code listIterator()}, and the {@code size} method
|
|
* merely returns the subclass's {@code size} field.
|
|
*
|
|
* <p>All methods first check to see if the actual {@code modCount} of
|
|
* the backing list is equal to its expected value, and throw a
|
|
* {@code ConcurrentModificationException} if it is not.
|
|
*
|
|
* @throws IndexOutOfBoundsException if an endpoint index value is out of range
|
|
* {@code (fromIndex < 0 || toIndex > size)}
|
|
* @throws IllegalArgumentException if the endpoint indices are out of order
|
|
* {@code (fromIndex > toIndex)}
|
|
*/
|
|
public List<E> subList(int fromIndex, int toIndex) {
|
|
subListRangeCheck(fromIndex, toIndex, size());
|
|
return (this instanceof RandomAccess ?
|
|
new RandomAccessSubList<>(this, fromIndex, toIndex) :
|
|
new SubList<>(this, fromIndex, toIndex));
|
|
}
|
|
|
|
static void subListRangeCheck(int fromIndex, int toIndex, int size) {
|
|
if (fromIndex < 0)
|
|
throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
|
|
if (toIndex > size)
|
|
throw new IndexOutOfBoundsException("toIndex = " + toIndex);
|
|
if (fromIndex > toIndex)
|
|
throw new IllegalArgumentException("fromIndex(" + fromIndex +
|
|
") > toIndex(" + toIndex + ")");
|
|
}
|
|
|
|
// Comparison and hashing
|
|
|
|
/**
|
|
* Compares the specified object with this list for equality. Returns
|
|
* {@code true} if and only if the specified object is also a list, both
|
|
* lists have the same size, and all corresponding pairs of elements in
|
|
* the two lists are <i>equal</i>. (Two elements {@code e1} and
|
|
* {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null :
|
|
* e1.equals(e2))}.) In other words, two lists are defined to be
|
|
* equal if they contain the same elements in the same order.
|
|
*
|
|
* @implSpec
|
|
* This implementation first checks if the specified object is this
|
|
* list. If so, it returns {@code true}; if not, it checks if the
|
|
* specified object is a list. If not, it returns {@code false}; if so,
|
|
* it iterates over both lists, comparing corresponding pairs of elements.
|
|
* If any comparison returns {@code false}, this method returns
|
|
* {@code false}. If either iterator runs out of elements before the
|
|
* other it returns {@code false} (as the lists are of unequal length);
|
|
* otherwise it returns {@code true} when the iterations complete.
|
|
*
|
|
* @param o the object to be compared for equality with this list
|
|
* @return {@code true} if the specified object is equal to this list
|
|
*/
|
|
public boolean equals(Object o) {
|
|
if (o == this)
|
|
return true;
|
|
if (!(o instanceof List))
|
|
return false;
|
|
|
|
ListIterator<E> e1 = listIterator();
|
|
ListIterator<?> e2 = ((List<?>) o).listIterator();
|
|
while (e1.hasNext() && e2.hasNext()) {
|
|
E o1 = e1.next();
|
|
Object o2 = e2.next();
|
|
if (!(o1==null ? o2==null : o1.equals(o2)))
|
|
return false;
|
|
}
|
|
return !(e1.hasNext() || e2.hasNext());
|
|
}
|
|
|
|
/**
|
|
* Returns the hash code value for this list.
|
|
*
|
|
* @implSpec
|
|
* This implementation uses exactly the code that is used to define the
|
|
* list hash function in the documentation for the {@link List#hashCode}
|
|
* method.
|
|
*
|
|
* @return the hash code value for this list
|
|
*/
|
|
public int hashCode() {
|
|
int hashCode = 1;
|
|
for (E e : this)
|
|
hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
|
|
return hashCode;
|
|
}
|
|
|
|
/**
|
|
* Removes from this list all of the elements whose index is between
|
|
* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
|
|
* Shifts any succeeding elements to the left (reduces their index).
|
|
* This call shortens the list by {@code (toIndex - fromIndex)} elements.
|
|
* (If {@code toIndex==fromIndex}, this operation has no effect.)
|
|
*
|
|
* <p>This method is called by the {@code clear} operation on this list
|
|
* and its subLists. Overriding this method to take advantage of
|
|
* the internals of the list implementation can <i>substantially</i>
|
|
* improve the performance of the {@code clear} operation on this list
|
|
* and its subLists.
|
|
*
|
|
* @implSpec
|
|
* This implementation gets a list iterator positioned before
|
|
* {@code fromIndex}, and repeatedly calls {@code ListIterator.next}
|
|
* followed by {@code ListIterator.remove} until the entire range has
|
|
* been removed. <b>Note: if {@code ListIterator.remove} requires linear
|
|
* time, this implementation requires quadratic time.</b>
|
|
*
|
|
* @param fromIndex index of first element to be removed
|
|
* @param toIndex index after last element to be removed
|
|
*/
|
|
protected void removeRange(int fromIndex, int toIndex) {
|
|
ListIterator<E> it = listIterator(fromIndex);
|
|
for (int i=0, n=toIndex-fromIndex; i<n; i++) {
|
|
it.next();
|
|
it.remove();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* The number of times this list has been <i>structurally modified</i>.
|
|
* Structural modifications are those that change the size of the
|
|
* list, or otherwise perturb it in such a fashion that iterations in
|
|
* progress may yield incorrect results.
|
|
*
|
|
* <p>This field is used by the iterator and list iterator implementation
|
|
* returned by the {@code iterator} and {@code listIterator} methods.
|
|
* If the value of this field changes unexpectedly, the iterator (or list
|
|
* iterator) will throw a {@code ConcurrentModificationException} in
|
|
* response to the {@code next}, {@code remove}, {@code previous},
|
|
* {@code set} or {@code add} operations. This provides
|
|
* <i>fail-fast</i> behavior, rather than non-deterministic behavior in
|
|
* the face of concurrent modification during iteration.
|
|
*
|
|
* <p><b>Use of this field by subclasses is optional.</b> If a subclass
|
|
* wishes to provide fail-fast iterators (and list iterators), then it
|
|
* merely has to increment this field in its {@code add(int, E)} and
|
|
* {@code remove(int)} methods (and any other methods that it overrides
|
|
* that result in structural modifications to the list). A single call to
|
|
* {@code add(int, E)} or {@code remove(int)} must add no more than
|
|
* one to this field, or the iterators (and list iterators) will throw
|
|
* bogus {@code ConcurrentModificationExceptions}. If an implementation
|
|
* does not wish to provide fail-fast iterators, this field may be
|
|
* ignored.
|
|
*/
|
|
protected transient int modCount = 0;
|
|
|
|
private void rangeCheckForAdd(int index) {
|
|
if (index < 0 || index > size())
|
|
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
|
|
}
|
|
|
|
private String outOfBoundsMsg(int index) {
|
|
return "Index: "+index+", Size: "+size();
|
|
}
|
|
|
|
/**
|
|
* An index-based split-by-two, lazily initialized Spliterator covering
|
|
* a List that access elements via {@link List#get}.
|
|
*
|
|
* If access results in an IndexOutOfBoundsException then a
|
|
* ConcurrentModificationException is thrown instead (since the list has
|
|
* been structurally modified while traversing).
|
|
*
|
|
* If the List is an instance of AbstractList then concurrent modification
|
|
* checking is performed using the AbstractList's modCount field.
|
|
*/
|
|
static final class RandomAccessSpliterator<E> implements Spliterator<E> {
|
|
|
|
private final List<E> list;
|
|
private int index; // current index, modified on advance/split
|
|
private int fence; // -1 until used; then one past last index
|
|
|
|
// The following fields are valid if covering an AbstractList
|
|
private final AbstractList<E> alist;
|
|
private int expectedModCount; // initialized when fence set
|
|
|
|
RandomAccessSpliterator(List<E> list) {
|
|
assert list instanceof RandomAccess;
|
|
|
|
this.list = list;
|
|
this.index = 0;
|
|
this.fence = -1;
|
|
|
|
this.alist = list instanceof AbstractList ? (AbstractList<E>) list : null;
|
|
this.expectedModCount = alist != null ? alist.modCount : 0;
|
|
}
|
|
|
|
/** Create new spliterator covering the given range */
|
|
private RandomAccessSpliterator(RandomAccessSpliterator<E> parent,
|
|
int origin, int fence) {
|
|
this.list = parent.list;
|
|
this.index = origin;
|
|
this.fence = fence;
|
|
|
|
this.alist = parent.alist;
|
|
this.expectedModCount = parent.expectedModCount;
|
|
}
|
|
|
|
private int getFence() { // initialize fence to size on first use
|
|
int hi;
|
|
List<E> lst = list;
|
|
if ((hi = fence) < 0) {
|
|
if (alist != null) {
|
|
expectedModCount = alist.modCount;
|
|
}
|
|
hi = fence = lst.size();
|
|
}
|
|
return hi;
|
|
}
|
|
|
|
public Spliterator<E> trySplit() {
|
|
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
|
|
return (lo >= mid) ? null : // divide range in half unless too small
|
|
new RandomAccessSpliterator<>(this, lo, index = mid);
|
|
}
|
|
|
|
public boolean tryAdvance(Consumer<? super E> action) {
|
|
if (action == null)
|
|
throw new NullPointerException();
|
|
int hi = getFence(), i = index;
|
|
if (i < hi) {
|
|
index = i + 1;
|
|
action.accept(get(list, i));
|
|
checkAbstractListModCount(alist, expectedModCount);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
public void forEachRemaining(Consumer<? super E> action) {
|
|
Objects.requireNonNull(action);
|
|
List<E> lst = list;
|
|
int hi = getFence();
|
|
int i = index;
|
|
index = hi;
|
|
for (; i < hi; i++) {
|
|
action.accept(get(lst, i));
|
|
}
|
|
checkAbstractListModCount(alist, expectedModCount);
|
|
}
|
|
|
|
public long estimateSize() {
|
|
return (long) (getFence() - index);
|
|
}
|
|
|
|
public int characteristics() {
|
|
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
|
|
}
|
|
|
|
private static <E> E get(List<E> list, int i) {
|
|
try {
|
|
return list.get(i);
|
|
} catch (IndexOutOfBoundsException ex) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
|
|
static void checkAbstractListModCount(AbstractList<?> alist, int expectedModCount) {
|
|
if (alist != null && alist.modCount != expectedModCount) {
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
}
|
|
}
|
|
|
|
private static class SubList<E> extends AbstractList<E> {
|
|
private final AbstractList<E> root;
|
|
private final SubList<E> parent;
|
|
private final int offset;
|
|
protected int size;
|
|
|
|
/**
|
|
* Constructs a sublist of an arbitrary AbstractList, which is
|
|
* not a SubList itself.
|
|
*/
|
|
public SubList(AbstractList<E> root, int fromIndex, int toIndex) {
|
|
this.root = root;
|
|
this.parent = null;
|
|
this.offset = fromIndex;
|
|
this.size = toIndex - fromIndex;
|
|
this.modCount = root.modCount;
|
|
}
|
|
|
|
/**
|
|
* Constructs a sublist of another SubList.
|
|
*/
|
|
protected SubList(SubList<E> parent, int fromIndex, int toIndex) {
|
|
this.root = parent.root;
|
|
this.parent = parent;
|
|
this.offset = parent.offset + fromIndex;
|
|
this.size = toIndex - fromIndex;
|
|
this.modCount = root.modCount;
|
|
}
|
|
|
|
public E set(int index, E element) {
|
|
Objects.checkIndex(index, size);
|
|
checkForComodification();
|
|
return root.set(offset + index, element);
|
|
}
|
|
|
|
public E get(int index) {
|
|
Objects.checkIndex(index, size);
|
|
checkForComodification();
|
|
return root.get(offset + index);
|
|
}
|
|
|
|
public int size() {
|
|
checkForComodification();
|
|
return size;
|
|
}
|
|
|
|
public void add(int index, E element) {
|
|
rangeCheckForAdd(index);
|
|
checkForComodification();
|
|
root.add(offset + index, element);
|
|
updateSizeAndModCount(1);
|
|
}
|
|
|
|
public E remove(int index) {
|
|
Objects.checkIndex(index, size);
|
|
checkForComodification();
|
|
E result = root.remove(offset + index);
|
|
updateSizeAndModCount(-1);
|
|
return result;
|
|
}
|
|
|
|
protected void removeRange(int fromIndex, int toIndex) {
|
|
checkForComodification();
|
|
root.removeRange(offset + fromIndex, offset + toIndex);
|
|
updateSizeAndModCount(fromIndex - toIndex);
|
|
}
|
|
|
|
public boolean addAll(Collection<? extends E> c) {
|
|
return addAll(size, c);
|
|
}
|
|
|
|
public boolean addAll(int index, Collection<? extends E> c) {
|
|
rangeCheckForAdd(index);
|
|
int cSize = c.size();
|
|
if (cSize==0)
|
|
return false;
|
|
checkForComodification();
|
|
root.addAll(offset + index, c);
|
|
updateSizeAndModCount(cSize);
|
|
return true;
|
|
}
|
|
|
|
public Iterator<E> iterator() {
|
|
return listIterator();
|
|
}
|
|
|
|
public ListIterator<E> listIterator(int index) {
|
|
checkForComodification();
|
|
rangeCheckForAdd(index);
|
|
|
|
return new ListIterator<E>() {
|
|
private final ListIterator<E> i =
|
|
root.listIterator(offset + index);
|
|
|
|
public boolean hasNext() {
|
|
return nextIndex() < size;
|
|
}
|
|
|
|
public E next() {
|
|
if (hasNext())
|
|
return i.next();
|
|
else
|
|
throw new NoSuchElementException();
|
|
}
|
|
|
|
public boolean hasPrevious() {
|
|
return previousIndex() >= 0;
|
|
}
|
|
|
|
public E previous() {
|
|
if (hasPrevious())
|
|
return i.previous();
|
|
else
|
|
throw new NoSuchElementException();
|
|
}
|
|
|
|
public int nextIndex() {
|
|
return i.nextIndex() - offset;
|
|
}
|
|
|
|
public int previousIndex() {
|
|
return i.previousIndex() - offset;
|
|
}
|
|
|
|
public void remove() {
|
|
i.remove();
|
|
updateSizeAndModCount(-1);
|
|
}
|
|
|
|
public void set(E e) {
|
|
i.set(e);
|
|
}
|
|
|
|
public void add(E e) {
|
|
i.add(e);
|
|
updateSizeAndModCount(1);
|
|
}
|
|
};
|
|
}
|
|
|
|
public List<E> subList(int fromIndex, int toIndex) {
|
|
subListRangeCheck(fromIndex, toIndex, size);
|
|
return new SubList<>(this, fromIndex, toIndex);
|
|
}
|
|
|
|
private void rangeCheckForAdd(int index) {
|
|
if (index < 0 || index > size)
|
|
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
|
|
}
|
|
|
|
private String outOfBoundsMsg(int index) {
|
|
return "Index: "+index+", Size: "+size;
|
|
}
|
|
|
|
private void checkForComodification() {
|
|
if (root.modCount != this.modCount)
|
|
throw new ConcurrentModificationException();
|
|
}
|
|
|
|
private void updateSizeAndModCount(int sizeChange) {
|
|
SubList<E> slist = this;
|
|
do {
|
|
slist.size += sizeChange;
|
|
slist.modCount = root.modCount;
|
|
slist = slist.parent;
|
|
} while (slist != null);
|
|
}
|
|
}
|
|
|
|
private static class RandomAccessSubList<E>
|
|
extends SubList<E> implements RandomAccess {
|
|
|
|
/**
|
|
* Constructs a sublist of an arbitrary AbstractList, which is
|
|
* not a RandomAccessSubList itself.
|
|
*/
|
|
RandomAccessSubList(AbstractList<E> root,
|
|
int fromIndex, int toIndex) {
|
|
super(root, fromIndex, toIndex);
|
|
}
|
|
|
|
/**
|
|
* Constructs a sublist of another RandomAccessSubList.
|
|
*/
|
|
RandomAccessSubList(RandomAccessSubList<E> parent,
|
|
int fromIndex, int toIndex) {
|
|
super(parent, fromIndex, toIndex);
|
|
}
|
|
|
|
public List<E> subList(int fromIndex, int toIndex) {
|
|
subListRangeCheck(fromIndex, toIndex, size);
|
|
return new RandomAccessSubList<>(this, fromIndex, toIndex);
|
|
}
|
|
}
|
|
}
|