< prev index next >
src/java.base/share/classes/java/util/List.java
Print this page
@@ -32,54 +32,54 @@
* interface has precise control over where in the list each element is
* inserted. The user can access elements by their integer index (position in
* the list), and search for elements in the list.<p>
*
* Unlike sets, lists typically allow duplicate elements. More formally,
- * lists typically allow pairs of elements <tt>e1</tt> and <tt>e2</tt>
- * such that <tt>e1.equals(e2)</tt>, and they typically allow multiple
+ * lists typically allow pairs of elements {@code e1} and {@code e2}
+ * such that {@code e1.equals(e2)}, and they typically allow multiple
* null elements if they allow null elements at all. It is not inconceivable
* that someone might wish to implement a list that prohibits duplicates, by
* throwing runtime exceptions when the user attempts to insert them, but we
* expect this usage to be rare.<p>
*
- * The <tt>List</tt> interface places additional stipulations, beyond those
- * specified in the <tt>Collection</tt> interface, on the contracts of the
- * <tt>iterator</tt>, <tt>add</tt>, <tt>remove</tt>, <tt>equals</tt>, and
- * <tt>hashCode</tt> methods. Declarations for other inherited methods are
+ * The {@code List} interface places additional stipulations, beyond those
+ * specified in the {@code Collection} interface, on the contracts of the
+ * {@code iterator}, {@code add}, {@code remove}, {@code equals}, and
+ * {@code hashCode} methods. Declarations for other inherited methods are
* also included here for convenience.<p>
*
- * The <tt>List</tt> interface provides four methods for positional (indexed)
+ * The {@code List} interface provides four methods for positional (indexed)
* access to list elements. Lists (like Java arrays) are zero based. Note
* that these operations may execute in time proportional to the index value
- * for some implementations (the <tt>LinkedList</tt> class, for
+ * for some implementations (the {@code LinkedList} class, for
* example). Thus, iterating over the elements in a list is typically
* preferable to indexing through it if the caller does not know the
* implementation.<p>
*
- * The <tt>List</tt> interface provides a special iterator, called a
- * <tt>ListIterator</tt>, that allows element insertion and replacement, and
+ * The {@code List} interface provides a special iterator, called a
+ * {@code ListIterator}, that allows element insertion and replacement, and
* bidirectional access in addition to the normal operations that the
- * <tt>Iterator</tt> interface provides. A method is provided to obtain a
+ * {@code Iterator} interface provides. A method is provided to obtain a
* list iterator that starts at a specified position in the list.<p>
*
- * The <tt>List</tt> interface provides two methods to search for a specified
+ * The {@code List} interface provides two methods to search for a specified
* object. From a performance standpoint, these methods should be used with
* caution. In many implementations they will perform costly linear
* searches.<p>
*
- * The <tt>List</tt> interface provides two methods to efficiently insert and
+ * The {@code List} interface provides two methods to efficiently insert and
* remove multiple elements at an arbitrary point in the list.<p>
*
* Note: While it is permissible for lists to contain themselves as elements,
- * extreme caution is advised: the <tt>equals</tt> and <tt>hashCode</tt>
+ * extreme caution is advised: the {@code equals} and {@code hashCode}
* methods are no longer well defined on such a list.
*
* <p>Some list implementations have restrictions on the elements that
* they may contain. For example, some implementations prohibit null elements,
* and some have restrictions on the types of their elements. Attempting to
* add an ineligible element throws an unchecked exception, typically
- * <tt>NullPointerException</tt> or <tt>ClassCastException</tt>. Attempting
+ * {@code NullPointerException} or {@code ClassCastException}. Attempting
* to query the presence of an ineligible element may throw an exception,
* or it may simply return false; some implementations will exhibit the former
* behavior and some will exhibit the latter. More generally, attempting an
* operation on an ineligible element whose completion would not result in
* the insertion of an ineligible element into the list may throw an
@@ -111,32 +111,32 @@
public interface List<E> extends Collection<E> {
// Query Operations
/**
* Returns the number of elements in this list. If this list contains
- * more than <tt>Integer.MAX_VALUE</tt> elements, returns
- * <tt>Integer.MAX_VALUE</tt>.
+ * more than {@code Integer.MAX_VALUE} elements, returns
+ * {@code Integer.MAX_VALUE}.
*
* @return the number of elements in this list
*/
int size();
/**
- * Returns <tt>true</tt> if this list contains no elements.
+ * Returns {@code true} if this list contains no elements.
*
- * @return <tt>true</tt> if this list contains no elements
+ * @return {@code true} if this list contains no elements
*/
boolean isEmpty();
/**
- * Returns <tt>true</tt> if this list contains the specified element.
- * More formally, returns <tt>true</tt> if and only if this list contains
- * at least one element <tt>e</tt> such that
- * <tt>(o==null ? e==null : o.equals(e))</tt>.
+ * Returns {@code true} if this list contains the specified element.
+ * More formally, returns {@code true} if and only if this list contains
+ * at least one element {@code e} such that
+ * <code>(o==null ? e==null : o.equals(e))</code>.
*
* @param o element whose presence in this list is to be tested
- * @return <tt>true</tt> if this list contains the specified element
+ * @return {@code true} if this list contains the specified element
* @throws ClassCastException if the type of the specified element
* is incompatible with this list
* (<a href="Collection.html#optional-restrictions">optional</a>)
* @throws NullPointerException if the specified element is null and this
* list does not permit null elements
@@ -177,29 +177,29 @@
* array is allocated with the runtime type of the specified array and
* the size of this list.
*
* <p>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 <tt>null</tt>.
+ * immediately following the end of the list is set to {@code null}.
* (This is useful in determining the length of the list <i>only</i> if
* the caller knows that the list does not contain any null elements.)
*
* <p>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.
*
- * <p>Suppose <tt>x</tt> is a list known to contain only strings.
+ * <p>Suppose {@code 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 <tt>String</tt>:
+ * allocated array of {@code String}:
*
* <pre>{@code
* String[] y = x.toArray(new String[0]);
* }</pre>
*
- * Note that <tt>toArray(new Object[0])</tt> is identical in function to
- * <tt>toArray()</tt>.
+ * Note that {@code toArray(new Object[0])} is identical in function to
+ * {@code toArray()}.
*
* @param a the array into which the elements of this list are to
* be stored, if it is big enough; otherwise, a new array of the
* same runtime type is allocated for this purpose.
* @return an array containing the elements of this list
@@ -223,12 +223,12 @@
* 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.
*
* @param e element to be appended to this list
- * @return <tt>true</tt> (as specified by {@link Collection#add})
- * @throws UnsupportedOperationException if the <tt>add</tt> operation
+ * @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
@@ -239,38 +239,38 @@
/**
* 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 <tt>i</tt> such that
- * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>
- * (if such an element exists). Returns <tt>true</tt> if this list
+ * the lowest index {@code i} such that
+ * <code>(o==null ? get(i)==null : o.equals(get(i)))</code>
+ * (if such an element exists). Returns {@code true} if this list
* contained the specified element (or equivalently, if this list changed
* as a result of the call).
*
* @param o element to be removed from this list, if present
- * @return <tt>true</tt> if this list contained the specified element
+ * @return {@code true} if this list contained the specified element
* @throws ClassCastException if the type of the specified element
* is incompatible with this list
* (<a href="Collection.html#optional-restrictions">optional</a>)
* @throws NullPointerException if the specified element is null and this
* list does not permit null elements
* (<a href="Collection.html#optional-restrictions">optional</a>)
- * @throws UnsupportedOperationException if the <tt>remove</tt> operation
+ * @throws UnsupportedOperationException if the {@code remove} operation
* is not supported by this list
*/
boolean remove(Object o);
// Bulk Modification Operations
/**
- * Returns <tt>true</tt> if this list contains all of the elements of the
+ * Returns {@code true} if this list contains all of the elements of the
* specified collection.
*
* @param c collection to be checked for containment in this list
- * @return <tt>true</tt> if this list contains all of the elements of the
+ * @return {@code true} if this list contains all of the elements of the
* specified collection
* @throws ClassCastException if the types of one or more elements
* in the specified collection are incompatible with this
* list
* (<a href="Collection.html#optional-restrictions">optional</a>)
@@ -290,12 +290,12 @@
* 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.)
*
* @param c collection containing elements to be added to this list
- * @return <tt>true</tt> if this list changed as a result of the call
- * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
+ * @return {@code true} if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the {@code addAll} operation
* is not supported by this list
* @throws ClassCastException if the class of an element of the specified
* collection prevents it from being added to this list
* @throws NullPointerException if the specified collection contains one
* or more null elements and this list does not permit null
@@ -318,32 +318,32 @@
* collection is this list, and it's nonempty.)
*
* @param index index at which to insert the first element from the
* specified collection
* @param c collection containing elements to be added to this list
- * @return <tt>true</tt> if this list changed as a result of the call
- * @throws UnsupportedOperationException if the <tt>addAll</tt> operation
+ * @return {@code true} if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the {@code addAll} operation
* is not supported by this list
* @throws ClassCastException if the class of an element of the specified
* collection prevents it from being added to this list
* @throws NullPointerException if the specified collection contains one
* or more null elements and this list does not permit null
* elements, or if the specified collection is null
* @throws IllegalArgumentException if some property of an element of the
* specified collection prevents it from being added to this list
* @throws IndexOutOfBoundsException if the index is out of range
- * (<tt>index < 0 || index > size()</tt>)
+ * ({@code index < 0 || index > size()})
*/
boolean addAll(int index, Collection<? extends E> c);
/**
* Removes from this list all of its elements that are contained in the
* specified collection (optional operation).
*
* @param c collection containing elements to be removed from this list
- * @return <tt>true</tt> if this list changed as a result of the call
- * @throws UnsupportedOperationException if the <tt>removeAll</tt> operation
+ * @return {@code true} if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the {@code removeAll} operation
* is not supported by this list
* @throws ClassCastException if the class of an element of this list
* is incompatible with the specified collection
* (<a href="Collection.html#optional-restrictions">optional</a>)
* @throws NullPointerException if this list contains a null element and the
@@ -360,12 +360,12 @@
* specified collection (optional operation). In other words, removes
* from this list all of its elements that are not contained in the
* specified collection.
*
* @param c collection containing elements to be retained in this list
- * @return <tt>true</tt> if this list changed as a result of the call
- * @throws UnsupportedOperationException if the <tt>retainAll</tt> operation
+ * @return {@code true} if this list changed as a result of the call
+ * @throws UnsupportedOperationException if the {@code retainAll} operation
* is not supported by this list
* @throws ClassCastException if the class of an element of this list
* is incompatible with the specified collection
* (<a href="Collection.html#optional-restrictions">optional</a>)
* @throws NullPointerException if this list contains a null element and the
@@ -485,31 +485,31 @@
/**
* Removes all of the elements from this list (optional operation).
* The list will be empty after this call returns.
*
- * @throws UnsupportedOperationException if the <tt>clear</tt> operation
+ * @throws UnsupportedOperationException if the {@code clear} operation
* is not supported by this list
*/
void clear();
// Comparison and hashing
/**
* Compares the specified object with this list for equality. Returns
- * <tt>true</tt> if and only if the specified object is also a list, both
+ * {@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 <tt>e1</tt> and
- * <tt>e2</tt> are <i>equal</i> if <tt>(e1==null ? e2==null :
- * e1.equals(e2))</tt>.) In other words, two lists are defined to be
+ * 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. This
* definition ensures that the equals method works properly across
- * different implementations of the <tt>List</tt> interface.
+ * different implementations of the {@code List} interface.
*
* @param o the object to be compared for equality with this list
- * @return <tt>true</tt> if the specified object is equal to this list
+ * @return {@code true} if the specified object is equal to this list
*/
boolean equals(Object o);
/**
* Returns the hash code value for this list. The hash code of a list
@@ -517,13 +517,13 @@
* <pre>{@code
* int hashCode = 1;
* for (E e : list)
* hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
* }</pre>
- * This ensures that <tt>list1.equals(list2)</tt> implies that
- * <tt>list1.hashCode()==list2.hashCode()</tt> for any two lists,
- * <tt>list1</tt> and <tt>list2</tt>, as required by the general
+ * This ensures that {@code list1.equals(list2)} implies that
+ * {@code list1.hashCode()==list2.hashCode()} for any two lists,
+ * {@code list1} and {@code list2}, as required by the general
* contract of {@link Object#hashCode}.
*
* @return the hash code value for this list
* @see Object#equals(Object)
* @see #equals(Object)
@@ -537,31 +537,31 @@
* Returns the element at the specified position in this list.
*
* @param index index of the element to return
* @return the element at the specified position in this list
* @throws IndexOutOfBoundsException if the index is out of range
- * (<tt>index < 0 || index >= size()</tt>)
+ * ({@code index < 0 || index >= size()})
*/
E get(int index);
/**
* Replaces the element at the specified position in this list with the
* specified element (optional operation).
*
* @param index index of the element to replace
* @param element element to be stored at the specified position
* @return the element previously at the specified position
- * @throws UnsupportedOperationException if the <tt>set</tt> operation
+ * @throws UnsupportedOperationException if the {@code set} 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 the specified
* element prevents it from being added to this list
* @throws IndexOutOfBoundsException if the index is out of range
- * (<tt>index < 0 || index >= size()</tt>)
+ * ({@code index < 0 || index >= size()})
*/
E set(int index, E element);
/**
* Inserts the specified element at the specified position in this list
@@ -569,20 +569,20 @@
* (if any) and any subsequent elements to the right (adds one to their
* indices).
*
* @param index index at which the specified element is to be inserted
* @param element element to be inserted
- * @throws UnsupportedOperationException if the <tt>add</tt> operation
+ * @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 the specified
* element prevents it from being added to this list
* @throws IndexOutOfBoundsException if the index is out of range
- * (<tt>index < 0 || index > size()</tt>)
+ * ({@code index < 0 || index > size()})
*/
void add(int index, E element);
/**
* Removes the element at the specified position in this list (optional
@@ -590,25 +590,25 @@
* from their indices). Returns the element that was removed from the
* list.
*
* @param index the index of the element to be removed
* @return the element previously at the specified position
- * @throws UnsupportedOperationException if the <tt>remove</tt> operation
+ * @throws UnsupportedOperationException if the {@code remove} operation
* is not supported by this list
* @throws IndexOutOfBoundsException if the index is out of range
- * (<tt>index < 0 || index >= size()</tt>)
+ * ({@code index < 0 || index >= size()})
*/
E remove(int index);
// Search Operations
/**
* 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 <tt>i</tt> such that
- * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
+ * More formally, returns the lowest index {@code i} such that
+ * <code>(o==null ? get(i)==null : o.equals(get(i)))</code>,
* or -1 if there is no such index.
*
* @param o element to search for
* @return the index of the first occurrence of the specified element in
* this list, or -1 if this list does not contain the element
@@ -622,12 +622,12 @@
int indexOf(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 <tt>i</tt> such that
- * <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
+ * More formally, returns the highest index {@code i} such that
+ * <code>(o==null ? get(i)==null : o.equals(get(i)))</code>,
* or -1 if there is no such index.
*
* @param o element to search for
* @return the index of the last occurrence of the specified element in
* this list, or -1 if this list does not contain the element
@@ -671,12 +671,12 @@
// View
/**
* Returns a view of the portion of this list between the specified
- * <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive. (If
- * <tt>fromIndex</tt> and <tt>toIndex</tt> are equal, the returned list is
+ * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. (If
+ * {@code fromIndex} and {@code 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.<p>
*
@@ -686,13 +686,13 @@
* instead of a whole list. For example, the following idiom
* removes a range of elements from a list:
* <pre>{@code
* list.subList(from, to).clear();
* }</pre>
- * Similar idioms may be constructed for <tt>indexOf</tt> and
- * <tt>lastIndexOf</tt>, and all of the algorithms in the
- * <tt>Collections</tt> class can be applied to a subList.<p>
+ * Similar idioms may be constructed for {@code indexOf} and
+ * {@code lastIndexOf}, and all of the algorithms in the
+ * {@code Collections} class can be applied to a subList.<p>
*
* The semantics of the list returned by this method become undefined if
* the backing list (i.e., this list) is <i>structurally modified</i> 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
@@ -700,12 +700,12 @@
*
* @param fromIndex low endpoint (inclusive) of the subList
* @param toIndex high endpoint (exclusive) of the subList
* @return a view of the specified range within this list
* @throws IndexOutOfBoundsException for an illegal endpoint index value
- * (<tt>fromIndex < 0 || toIndex > size ||
- * fromIndex > toIndex</tt>)
+ * ({@code fromIndex < 0 || toIndex > size ||
+ * fromIndex > toIndex})
*/
List<E> subList(int fromIndex, int toIndex);
/**
* Creates a {@link Spliterator} over the elements in this list.
< prev index next >