com.google.common.collect
Class ImmutableBiMap<K,V>

java.lang.Object
  com.google.common.collect.ImmutableMap<K,V>
      com.google.common.collect.ImmutableBiMap<K,V>

All Implemented Interfaces:

BiMap<K,V>, Serializable, Map<K,V>

@GwtCompatible(serializable=true,
               emulated=true)
public abstract class ImmutableBiMap<K,V>
extends ImmutableMap<K,V>
implements BiMap<K,V>

An immutable BiMap with reliable user-specified iteration order. Does not permit null keys or values. An ImmutableBiMap and its inverse have the same iteration ordering.

An instance of ImmutableBiMap contains its own data and will never change. ImmutableBiMap is convenient for public static final maps ("constant maps") and also lets you easily make a "defensive copy" of a bimap 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 class are guaranteed to be immutable.

Since:

2 (imported from Google Collections Library)

Author:

Jared Levy

See Also:

Serialized Form

of

public static <K,V> ImmutableBiMap<K,V> of()

Returns the empty bimap.

of

public static <K,V> ImmutableBiMap<K,V> of(K k1,
                                           V v1)

Returns an immutable bimap containing a single entry.

of

public static <K,V> ImmutableBiMap<K,V> of(K k1,
                                           V v1,
                                           K k2,
                                           V v2)

Returns an immutable map containing the given entries, in order.

Throws:

IllegalArgumentException - if duplicate keys or values are added

of

public static <K,V> ImmutableBiMap<K,V> of(K k1,
                                           V v1,
                                           K k2,
                                           V v2,
                                           K k3,
                                           V v3)

Returns an immutable map containing the given entries, in order.

Throws:

IllegalArgumentException - if duplicate keys or values are added

of

public static <K,V> ImmutableBiMap<K,V> of(K k1,
                                           V v1,
                                           K k2,
                                           V v2,
                                           K k3,
                                           V v3,
                                           K k4,
                                           V v4)

Returns an immutable map containing the given entries, in order.

Throws:

IllegalArgumentException - if duplicate keys or values are added

of

public static <K,V> ImmutableBiMap<K,V> of(K k1,
                                           V v1,
                                           K k2,
                                           V v2,
                                           K k3,
                                           V v3,
                                           K k4,
                                           V v4,
                                           K k5,
                                           V v5)

Returns an immutable map containing the given entries, in order.

Throws:

IllegalArgumentException - if duplicate keys or values are added

builder

public static <K,V> ImmutableBiMap.Builder<K,V> builder()

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

copyOf

public static <K,V> ImmutableBiMap<K,V> copyOf(Map<? extends K,? extends V> map)

Returns an immutable bimap containing the same entries as map. If map somehow contains entries with duplicate keys (for example, if it is a SortedMap whose comparator is not consistent with equals), the results of this method are undefined.

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.

Throws:

IllegalArgumentException - if two keys have the same value

NullPointerException - if any key or value in map is null

inverse

public abstract ImmutableBiMap<V,K> inverse()

Returns the inverse view of this bimap, which maps each of this bimap's values to its associated key. The two bimaps are backed by the same data; any changes to one will appear in the other.

Note:There is no guaranteed correspondence between the iteration order of a bimap and that of its inverse.

The inverse of an ImmutableBiMap is another ImmutableBiMap.

Specified by:

inverse in interface BiMap<K,V>

Returns:

the inverse view of this bimap

containsKey

public boolean containsKey(@Nullable
                           Object key)

Description copied from interface: java.util.Map

Returns true if this map contains a mapping for the specified key. More formally, returns true if and only if this map contains a mapping for a key k such that (key==null ? k==null : key.equals(k)). (There can be at most one such mapping.)

Specified by:

containsKey in interface Map<K,V>

Overrides:

containsKey in class ImmutableMap<K,V>

Parameters:

key - key whose presence in this map is to be tested

Returns:

true if this map contains a mapping for the specified key

containsValue

public boolean containsValue(@Nullable
                             Object value)

Description copied from interface: java.util.Map

Returns true if this map maps one or more keys to the specified value. More formally, returns true if and only if this map contains at least one mapping to a value v such that (value==null ? v==null : value.equals(v)). This operation will probably require time linear in the map size for most implementations of the Map interface.

Specified by:

containsValue in interface Map<K,V>

Specified by:

containsValue in class ImmutableMap<K,V>

Parameters:

value - value whose presence in this map is to be tested

Returns:

true if this map maps one or more keys to the specified value

entrySet

public ImmutableSet<Map.Entry<K,V>> entrySet()

Description copied from class: ImmutableMap

Returns an immutable set of the mappings in this map. The entries are in the same order as the parameters used to build this map.

Specified by:

entrySet in interface Map<K,V>

Specified by:

entrySet in class ImmutableMap<K,V>

Returns:

a set view of the mappings contained in this map

get

public V get(@Nullable
             Object key)

Description copied from interface: java.util.Map

Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

More formally, if this map contains a mapping from a key k to a value v such that (key==null ? k==null : key.equals(k)), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

If this map permits null values, then a return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

Specified by:

get in interface Map<K,V>

Specified by:

get in class ImmutableMap<K,V>

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which the specified key is mapped, or null if this map contains no mapping for the key

keySet

public ImmutableSet<K> keySet()

Description copied from class: ImmutableMap

Returns an immutable set of the keys in this map. These keys are in the same order as the parameters used to build this map.

Specified by:

keySet in interface Map<K,V>

Specified by:

keySet in class ImmutableMap<K,V>

Returns:

a set view of the keys contained in this map

values

public ImmutableSet<V> values()

Returns an immutable set of the values in this map. The values are in the same order as the parameters used to build this map.

Specified by:

values in interface BiMap<K,V>

Specified by:

values in interface Map<K,V>

Specified by:

values in class ImmutableMap<K,V>

Returns:

a collection view of the values contained in this map

forcePut

public V forcePut(K key,
                  V value)

Guaranteed to throw an exception and leave the bimap unmodified.

Specified by:

forcePut in interface BiMap<K,V>

Parameters:

key - the key with which the specified value is to be associated

value - the value to be associated with the specified key

Returns:

the value which was previously associated with the key, which may be null, or null if there was no previous entry

Throws:

UnsupportedOperationException - always

isEmpty

public boolean isEmpty()

Description copied from interface: java.util.Map

Returns true if this map contains no key-value mappings.

Specified by:

isEmpty in interface Map<K,V>

Overrides:

isEmpty in class ImmutableMap<K,V>

Returns:

true if this map contains no key-value mappings

size

public int size()

Description copied from interface: java.util.Map

Returns the number of key-value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Map<K,V>

Returns:

the number of key-value mappings in this map

equals

public boolean equals(@Nullable
                      Object object)

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 Map<K,V>

Overrides:

equals in class ImmutableMap<K,V>

Parameters:

object - 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(), Hashtable

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 hashtables such as those provided by java.util.Hashtable.

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 hashtables.

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 Map<K,V>

Overrides:

hashCode in class ImmutableMap<K,V>

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

toString

public String toString()

Description copied from class: java.lang.Object

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class ImmutableMap<K,V>

Returns:

a string representation of the object.