| Methods Summary |
|---|
| public void | add(int index, E element)Inserts the specified element at the specified position in this list
(optional operation). Shifts the element currently at that position
(if any) and any subsequent elements to the right (adds one to their
indices).
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| public boolean | add(E e)Appends the specified element to the end of this list (optional
operation).
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.
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| public boolean | addAll(java.util.Collection c)Appends all of the elements in the specified collection to the end of
this list, in the order that they are returned by the specified
collection's iterator (optional operation). The behavior of this
operation is undefined if the specified collection is modified while
the operation is in progress. (Note that this will occur if the
specified collection is this list, and it's nonempty.)
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| public boolean | addAll(int index, java.util.Collection c)Inserts all of the elements in the specified collection into this
list at the specified position (optional operation). Shifts the
element currently at that position (if any) and any subsequent
elements to the right (increases their indices). The new elements
will appear in this list in the order that they are returned by the
specified collection's iterator. The behavior of this operation is
undefined if the specified collection is modified while the
operation is in progress. (Note that this will occur if the specified
collection is this list, and it's nonempty.)
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| public void | clear()Removes all of the elements from this list (optional operation).
The list will be empty after this call returns.
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| public boolean | contains(java.lang.Object o)Returns true if this list contains the specified element.
More formally, returns true if and only if this list contains
at least one element e such that
(o==null ? e==null : o.equals(e)).
|
| public boolean | containsAll(java.util.Collection c)Returns true if this list contains all of the elements of the
specified collection.
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| public boolean | equals(java.lang.Object o)Compares the specified object with this list for equality. Returns
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 equal. (Two elements e1 and
e2 are equal if (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. This
definition ensures that the equals method works properly across
different implementations of the List interface.
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| public E | get(int index)Returns the element at the specified position in this list.
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| public int | hashCode()Returns the hash code value for this list. The hash code of a list
is defined to be the result of the following calculation:
int hashCode = 1;
Iterator<E> i = list.iterator();
while (i.hasNext()) {
E obj = i.next();
hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode());
}
This ensures that list1.equals(list2) implies that
list1.hashCode()==list2.hashCode() for any two lists,
list1 and list2, as required by the general
contract of {@link Object#hashCode}.
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| public int | indexOf(java.lang.Object o)Returns the index of the first occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the lowest index i such that
(o==null ? get(i)==null : o.equals(get(i))),
or -1 if there is no such index.
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| public boolean | isEmpty()Returns true if this list contains no elements.
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| public java.util.Iterator | iterator()Returns an iterator over the elements in this list in proper sequence.
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| public int | lastIndexOf(java.lang.Object o)Returns the index of the last occurrence of the specified element
in this list, or -1 if this list does not contain the element.
More formally, returns the highest index i such that
(o==null ? get(i)==null : o.equals(get(i))),
or -1 if there is no such index.
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| public java.util.ListIterator | listIterator()Returns a list iterator over the elements in this list (in proper
sequence).
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| public java.util.ListIterator | listIterator(int index)Returns a list iterator of the elements in this list (in proper
sequence), starting at the specified position in this list.
The specified index indicates the first element that would be
returned by an initial call to {@link ListIterator#next next}.
An initial call to {@link ListIterator#previous previous} would
return the element with the specified index minus one.
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| public E | remove(int index)Removes the element at the specified position in this list (optional
operation). Shifts any subsequent elements to the left (subtracts one
from their indices). Returns the element that was removed from the
list.
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| public boolean | remove(java.lang.Object o)Removes the first occurrence of the specified element from this list,
if it is present (optional operation). If this list does not contain
the element, it is unchanged. More formally, removes the element with
the lowest index i such that
(o==null ? get(i)==null : o.equals(get(i)))
(if such an element exists). Returns true if this list
contained the specified element (or equivalently, if this list changed
as a result of the call).
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| public boolean | removeAll(java.util.Collection c)Removes from this list all of its elements that are contained in the
specified collection (optional operation).
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| public boolean | retainAll(java.util.Collection c)Retains only the elements in this list that are contained in the
specified collection (optional operation). In other words, removes
from this list all the elements that are not contained in the specified
collection.
|
| public E | set(int index, E element)Replaces the element at the specified position in this list with the
specified element (optional operation).
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| public int | size()Returns the number of elements in this list. If this list contains
more than Integer.MAX_VALUE elements, returns
Integer.MAX_VALUE.
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| public java.util.List | subList(int fromIndex, int toIndex)Returns a view of the portion of this list between the specified
fromIndex, inclusive, and toIndex, exclusive. (If
fromIndex and toIndex are equal, the returned list is
empty.) The returned list is backed by this list, so non-structural
changes in the returned list are reflected in this list, and vice-versa.
The returned list supports all of the optional list operations supported
by this list.
This method eliminates the need for explicit range operations (of
the sort that commonly exist for arrays). Any operation that expects
a list can be used as a range operation by passing a subList view
instead of a whole list. For example, the following idiom
removes a range of elements from a list:
list.subList(from, to).clear();
Similar idioms may be constructed for indexOf and
lastIndexOf, and all of the algorithms in the
Collections class can be applied to a subList.
The semantics of the list returned by this method become undefined if
the backing list (i.e., this list) is structurally modified in
any way other than via the returned list. (Structural modifications are
those that change the size of this list, or otherwise perturb it in such
a fashion that iterations in progress may yield incorrect results.)
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| public java.lang.Object[] | toArray()Returns an array containing all of the elements in this list in proper
sequence (from first to last element).
The returned array will be "safe" in that no references to it are
maintained by this list. (In other words, this method must
allocate a new array even if this list is backed by an array).
The caller is thus free to modify the returned array.
This method acts as bridge between array-based and collection-based
APIs.
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| public T[] | toArray(T[] a)Returns an array containing all of the elements in this list in
proper sequence (from first to last element); the runtime type of
the returned array is that of the specified array. If the list fits
in the specified array, it is returned therein. Otherwise, a new
array is allocated with the runtime type of the specified array and
the size of this list.
If the list fits in the specified array with room to spare (i.e.,
the array has more elements than the list), the element in the array
immediately following the end of the list is set to null.
(This is useful in determining the length of the list only if
the caller knows that the list does not contain any null elements.)
Like the {@link #toArray()} method, this method acts as bridge between
array-based and collection-based APIs. Further, this method allows
precise control over the runtime type of the output array, and may,
under certain circumstances, be used to save allocation costs.
Suppose x is a list known to contain only strings.
The following code can be used to dump the list into a newly
allocated array of String:
String[] y = x.toArray(new String[0]);
Note that toArray(new Object[0]) is identical in function to
toArray().
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