com.google.common.collect

Class ImmutableList<E>

java.lang.Object

java.util.AbstractCollection<E>

com.google.common.collect.ImmutableCollection<E>

com.google.common.collect.ImmutableList<E>

All Implemented Interfaces:

Serializable, Iterable<E>, Collection<E>, List<E>, RandomAccess

@GwtCompatible(serializable=true,
               emulated=true)
public abstract class ImmutableList<E>
extends ImmutableCollection<E>
implements List<E>, RandomAccess

A high-performance, immutable, random-access List implementation. Does not permit null elements.

Unlike Collections#unmodifiableList, which is a view of a separate collection that can still change, an instance of ImmutableList contains its own private data and will never change. ImmutableList is convenient for public static final lists ("constant lists") and also lets you easily make a "defensive copy" of a list provided to your class by a caller.

Note: Although this class is not final, it cannot be subclassed as it has no public or protected constructors. Thus, instances of this type are guaranteed to be immutable.

See the Guava User Guide article on immutable collections.

Since:

2.0 (imported from Google Collections Library)

Author:

Kevin Bourrillion

See Also:

ImmutableMap, ImmutableSet, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ImmutableList.Builder<E> A builder for creating immutable list instances, especially public static final lists ("constant lists").

Method Summary

Methods

Modifier and Type	Method and Description
void	add(int index, E element) Deprecated. Unsupported operation.
boolean	addAll(int index, Collection<? extends E> newElements) Deprecated. Unsupported operation.
ImmutableList<E>	asList() Returns this list instance.
static <E> ImmutableList.Builder<E>	builder() Returns a new builder.
boolean	contains(Object object) Returns true if this collection contains the specified element.
static <E> ImmutableList<E>	copyOf(Collection<? extends E> elements) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	copyOf(E[] elements) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	copyOf(Iterable<? extends E> elements) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	copyOf(Iterator<? extends E> elements) Returns an immutable list containing the given elements, in order.
boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
int	hashCode() Returns a hash code value for the object.
int	indexOf(Object object) Returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.
UnmodifiableIterator<E>	iterator() Returns an unmodifiable iterator across the elements in this collection.
int	lastIndexOf(Object object) Returns the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element.
UnmodifiableListIterator<E>	listIterator() Returns a list iterator over the elements in this list (in proper sequence).
UnmodifiableListIterator<E>	listIterator(int index) Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list.
static <E> ImmutableList<E>	of() Returns the empty immutable list.
static <E> ImmutableList<E>	of(E element) Returns an immutable list containing a single element.
static <E> ImmutableList<E>	of(E e1, E e2) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10, E e11) Returns an immutable list containing the given elements, in order.
static <E> ImmutableList<E>	of(E e1, E e2, E e3, E e4, E e5, E e6, E e7, E e8, E e9, E e10, E e11, E e12, E... others) Returns an immutable list containing the given elements, in order.
E	remove(int index) Deprecated. Unsupported operation.
ImmutableList<E>	reverse() Returns a view of this immutable list in reverse order.
E	set(int index, E element) Deprecated. Unsupported operation.
ImmutableList<E>	subList(int fromIndex, int toIndex) Returns an immutable list of the elements between the specified fromIndex, inclusive, and toIndex, exclusive.

Methods inherited from class com.google.common.collect.ImmutableCollection

add, addAll, clear, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, size, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

add, addAll, clear, containsAll, get, isEmpty, remove, removeAll, retainAll, size, toArray, toArray

Method Detail

of

public static <E> ImmutableList<E> of()

Returns the empty immutable list. This set behaves and performs comparably to Collections#emptyList, and is preferable mainly for consistency and maintainability of your code.

of

public static <E> ImmutableList<E> of(E element)

Returns an immutable list containing a single element. This list behaves and performs comparably to Collections#singleton, but will not accept a null element. It is preferable mainly for consistency and maintainability of your code.

Throws:

NullPointerException - if element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7,
                      E e8)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7,
                      E e8,
                      E e9)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7,
                      E e8,
                      E e9,
                      E e10)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7,
                      E e8,
                      E e9,
                      E e10,
                      E e11)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

of

public static <E> ImmutableList<E> of(E e1,
                      E e2,
                      E e3,
                      E e4,
                      E e5,
                      E e6,
                      E e7,
                      E e8,
                      E e9,
                      E e10,
                      E e11,
                      E e12,
                      E... others)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any element is null

Since:

3.0 (source-compatible since 2.0)

copyOf

public static <E> ImmutableList<E> copyOf(Iterable<? extends E> elements)

Returns an immutable list containing the given elements, in order. If elements is a Collection, this method behaves exactly as copyOf(Collection); otherwise, it behaves exactly as copyOf(elements.iterator().

Throws:

NullPointerException - if any of elements is null

copyOf

public static <E> ImmutableList<E> copyOf(Collection<? extends E> elements)

Returns an immutable list containing the given elements, in order.

Despite the method name, this method attempts to avoid actually copying the data when it is safe to do so. The exact circumstances under which a copy will or will not be performed are undocumented and subject to change.

Note that if list is a List<String>, then ImmutableList.copyOf(list) returns an ImmutableList<String> containing each of the strings in list, while ImmutableList.of(list)} returns an ImmutableList<List<String>> containing one element (the given list itself).

This method is safe to use even when elements is a synchronized or concurrent collection that is currently being modified by another thread.

Throws:

NullPointerException - if any of elements is null

copyOf

public static <E> ImmutableList<E> copyOf(Iterator<? extends E> elements)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any of elements is null

copyOf

public static <E> ImmutableList<E> copyOf(E[] elements)

Returns an immutable list containing the given elements, in order.

Throws:

NullPointerException - if any of elements is null

Since:

3.0

iterator

public UnmodifiableIterator<E> iterator()

Description copied from class: ImmutableCollection

Returns an unmodifiable iterator across the elements in this collection.

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in interface List<E>

Specified by:

iterator in class ImmutableCollection<E>

Returns:

an iterator over the elements contained in this collection

listIterator

public UnmodifiableListIterator<E> listIterator()

Description copied from interface: java.util.List

Returns a list iterator over the elements in this list (in proper sequence).

Specified by:

listIterator in interface List<E>

Returns:

a list iterator over the elements in this list (in proper sequence)

listIterator

public UnmodifiableListIterator<E> listIterator(int index)

Description copied from interface: java.util.List

Returns a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list. The specified index indicates the first element that would be returned by an initial call to next. An initial call to previous would return the element with the specified index minus one.

Specified by:

listIterator in interface List<E>

Parameters:

index - index of the first element to be returned from the list iterator (by a call to next)

Returns:

a list iterator over the elements in this list (in proper sequence), starting at the specified position in the list

indexOf

public int indexOf(@Nullable
          Object object)

Description copied from interface: java.util.List

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.

Specified by:

indexOf in interface List<E>

Parameters:

object - element to search for

Returns:

the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element

lastIndexOf

public int lastIndexOf(@Nullable
              Object object)

Description copied from interface: java.util.List

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.

Specified by:

lastIndexOf in interface List<E>

Parameters:

object - element to search for

Returns:

the index of the last occurrence of the specified element in this list, or -1 if this list does not contain the element

contains

public boolean contains(@Nullable
               Object object)

Description copied from class: java.util.AbstractCollection

Returns true if this collection contains the specified element. More formally, returns true if and only if this collection contains at least one element e such that (o==null ? e==null : o.equals(e)).

This implementation iterates over the elements in the collection, checking each element in turn for equality with the specified element.

Specified by:

contains in interface Collection<E>

Specified by:

contains in interface List<E>

Overrides:

contains in class ImmutableCollection<E>

Parameters:

object - element whose presence in this collection is to be tested

Returns:

true if this collection contains the specified element

subList

public ImmutableList<E> subList(int fromIndex,
                       int toIndex)

Returns an immutable list of the elements between the specified fromIndex, inclusive, and toIndex, exclusive. (If fromIndex and toIndex are equal, the empty immutable list is returned.)

Specified by:

subList in interface List<E>

Parameters:

fromIndex - low endpoint (inclusive) of the subList

toIndex - high endpoint (exclusive) of the subList

Returns:

a view of the specified range within this list

addAll

@Deprecated
public final boolean addAll(int index,
                        Collection<? extends E> newElements)

Deprecated. Unsupported operation.

Guaranteed to throw an exception and leave the list unmodified.

Specified by:

addAll in interface List<E>

Parameters:

index - index at which to insert the first element from the specified collection

newElements - collection containing elements to be added to this list

Returns:

true if this list changed as a result of the call

Throws:

UnsupportedOperationException - always

set

@Deprecated
public final E set(int index,
               E element)

Deprecated. Unsupported operation.

Guaranteed to throw an exception and leave the list unmodified.

Specified by:

set in interface List<E>

Parameters:

index - index of the element to replace

element - element to be stored at the specified position

Returns:

the element previously at the specified position

Throws:

UnsupportedOperationException - always

add

@Deprecated
public final void add(int index,
                  E element)

Deprecated. Unsupported operation.

Guaranteed to throw an exception and leave the list unmodified.

Specified by:

add in interface List<E>

Parameters:

index - index at which the specified element is to be inserted

element - element to be inserted

Throws:

UnsupportedOperationException - always

remove

@Deprecated
public final E remove(int index)

Deprecated. Unsupported operation.

Guaranteed to throw an exception and leave the list unmodified.

Specified by:

remove in interface List<E>

Parameters:

index - the index of the element to be removed

Returns:

the element previously at the specified position

Throws:

UnsupportedOperationException - always

asList

public final ImmutableList<E> asList()

Returns this list instance.

Overrides:

asList in class ImmutableCollection<E>

Since:

2.0

reverse

public ImmutableList<E> reverse()

Returns a view of this immutable list in reverse order. For example, ImmutableList.of(1, 2, 3).reverse() is equivalent to ImmutableList.of(3, 2, 1).

Returns:

a view of this immutable list in reverse order

Since:

7.0

equals

public boolean equals(@Nullable
             Object obj)

Description copied from class: java.lang.Object

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

• It is reflexive: for any non-null reference value x, x.equals(x) should return true.
• It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
• It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
• It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
• For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Specified by:

equals in interface Collection<E>

Specified by:

equals in interface List<E>

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), HashMap

hashCode

public int hashCode()

Description copied from class: java.lang.Object

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

• Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
• If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
• It is not required that if two objects are unequal according to the Object.equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java^TM programming language.)

Specified by:

hashCode in interface Collection<E>

Specified by:

hashCode in interface List<E>

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

builder

public static <E> ImmutableList.Builder<E> builder()

Returns a new builder. The generated builder is equivalent to the builder created by the ImmutableList.Builder constructor.