com.google.common.collect

Interface Table<R,C,V>

Type Parameters:

R - the type of the table row keys

C - the type of the table column keys

V - the type of the mapped values

All Known Subinterfaces:

RowSortedTable<R,C,V>

All Known Implementing Classes:

ArrayTable, ForwardingTable, HashBasedTable, ImmutableTable, TreeBasedTable

@GwtCompatible
public interface Table<R,C,V>

A collection that associates an ordered pair of keys, called a row key and a column key, with a single value. A table may be sparse, with only a small fraction of row key / column key pairs possessing a corresponding value.

The mappings corresponding to a given row key may be viewed as a Map whose keys are the columns. The reverse is also available, associating a column with a row key / value map. Note that, in some implementations, data access by column key may have fewer supported operations or worse performance than data access by row key.

The methods returning collections or maps always return views of the underlying table. Updating the table can change the contents of those collections, and updating the collections will change the table.

All methods that modify the table are optional, and the views returned by the table may or may not be modifiable. When modification isn't supported, those methods will throw an UnsupportedOperationException.

See the Guava User Guide article on Table.

Since:

7.0

Author:

Jared Levy

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Table.Cell<R,C,V> Row key / column key / value triplet corresponding to a mapping in a table.

Method Summary

Methods

Modifier and Type	Method and Description
Set<Table.Cell<R,C,V>>	cellSet() Returns a set of all row key / column key / value triplets.
void	clear() Removes all mappings from the table.
Map<R,V>	column(C columnKey) Returns a view of all mappings that have the given column key.
Set<C>	columnKeySet() Returns a set of column keys that have one or more values in the table.
Map<C,Map<R,V>>	columnMap() Returns a view that associates each column key with the corresponding map from row keys to values.
boolean	contains(Object rowKey, Object columnKey) Returns true if the table contains a mapping with the specified row and column keys.
boolean	containsColumn(Object columnKey) Returns true if the table contains a mapping with the specified column.
boolean	containsRow(Object rowKey) Returns true if the table contains a mapping with the specified row key.
boolean	containsValue(Object value) Returns true if the table contains a mapping with the specified value.
boolean	equals(Object obj) Compares the specified object with this table for equality.
V	get(Object rowKey, Object columnKey) Returns the value corresponding to the given row and column keys, or null if no such mapping exists.
int	hashCode() Returns the hash code for this table.
boolean	isEmpty() Returns true if the table contains no mappings.
V	put(R rowKey, C columnKey, V value) Associates the specified value with the specified keys.
void	putAll(Table<? extends R,? extends C,? extends V> table) Copies all mappings from the specified table to this table.
V	remove(Object rowKey, Object columnKey) Removes the mapping, if any, associated with the given keys.
Map<C,V>	row(R rowKey) Returns a view of all mappings that have the given row key.
Set<R>	rowKeySet() Returns a set of row keys that have one or more values in the table.
Map<R,Map<C,V>>	rowMap() Returns a view that associates each row key with the corresponding map from column keys to values.
int	size() Returns the number of row key / column key / value mappings in the table.
Collection<V>	values() Returns a collection of all values, which may contain duplicates.

Method Detail

contains

boolean contains(@Nullable
               Object rowKey,
               @Nullable
               Object columnKey)

Returns true if the table contains a mapping with the specified row and column keys.

Parameters:

rowKey - key of row to search for

columnKey - key of column to search for

containsRow

boolean containsRow(@Nullable
                  Object rowKey)

Returns true if the table contains a mapping with the specified row key.

Parameters:

rowKey - key of row to search for

containsColumn

boolean containsColumn(@Nullable
                     Object columnKey)

Returns true if the table contains a mapping with the specified column.

Parameters:

columnKey - key of column to search for

containsValue

boolean containsValue(@Nullable
                    Object value)

Returns true if the table contains a mapping with the specified value.

Parameters:

value - value to search for

get

V get(@Nullable
    Object rowKey,
    @Nullable
    Object columnKey)

Returns the value corresponding to the given row and column keys, or null if no such mapping exists.

Parameters:

rowKey - key of row to search for

columnKey - key of column to search for

isEmpty

boolean isEmpty()

Returns true if the table contains no mappings.

size

int size()

Returns the number of row key / column key / value mappings in the table.

equals

boolean equals(@Nullable
             Object obj)

Compares the specified object with this table for equality. Two tables are equal when their cell views, as returned by cellSet(), are equal.

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

int hashCode()

Returns the hash code for this table. The hash code of a table is defined as the hash code of its cell view, as returned by cellSet().

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)

clear

void clear()

Removes all mappings from the table.

put

V put(R rowKey,
    C columnKey,
    V value)

Associates the specified value with the specified keys. If the table already contained a mapping for those keys, the old value is replaced with the specified value.

Parameters:

rowKey - row key that the value should be associated with

columnKey - column key that the value should be associated with

value - value to be associated with the specified keys

Returns:

the value previously associated with the keys, or null if no mapping existed for the keys

putAll

void putAll(Table<? extends R,? extends C,? extends V> table)

Copies all mappings from the specified table to this table. The effect is equivalent to calling put(R, C, V) with each row key / column key / value mapping in table.

Parameters:

table - the table to add to this table

remove

V remove(@Nullable
       Object rowKey,
       @Nullable
       Object columnKey)

Removes the mapping, if any, associated with the given keys.

Parameters:

rowKey - row key of mapping to be removed

columnKey - column key of mapping to be removed

Returns:

the value previously associated with the keys, or null if no such value existed

row

Map<C,V> row(R rowKey)

Returns a view of all mappings that have the given row key. For each row key / column key / value mapping in the table with that row key, the returned map associates the column key with the value. If no mappings in the table have the provided row key, an empty map is returned.

Changes to the returned map will update the underlying table, and vice versa.

Parameters:

rowKey - key of row to search for in the table

Returns:

the corresponding map from column keys to values

column

Map<R,V> column(C columnKey)

Returns a view of all mappings that have the given column key. For each row key / column key / value mapping in the table with that column key, the returned map associates the row key with the value. If no mappings in the table have the provided column key, an empty map is returned.

Changes to the returned map will update the underlying table, and vice versa.

Parameters:

columnKey - key of column to search for in the table

Returns:

the corresponding map from row keys to values

cellSet

Set<Table.Cell<R,C,V>> cellSet()

Returns a set of all row key / column key / value triplets. Changes to the returned set will update the underlying table, and vice versa. The cell set does not support the add or addAll methods.

Returns:

set of table cells consisting of row key / column key / value triplets

rowKeySet

Set<R> rowKeySet()

Returns a set of row keys that have one or more values in the table. Changes to the set will update the underlying table, and vice versa.

Returns:

set of row keys

columnKeySet

Set<C> columnKeySet()

Returns a set of column keys that have one or more values in the table. Changes to the set will update the underlying table, and vice versa.

Returns:

set of column keys

values

Collection<V> values()

Returns a collection of all values, which may contain duplicates. Changes to the returned collection will update the underlying table, and vice versa.

Returns:

collection of values

rowMap

Map<R,Map<C,V>> rowMap()

Returns a view that associates each row key with the corresponding map from column keys to values. Changes to the returned map will update this table. The returned map does not support put() or putAll(), or setValue() on its entries.

In contrast, the maps returned by rowMap().get() have the same behavior as those returned by row(R). Those maps may support setValue(), put(), and putAll().

Returns:

a map view from each row key to a secondary map from column keys to values

columnMap

Map<C,Map<R,V>> columnMap()

Returns a view that associates each column key with the corresponding map from row keys to values. Changes to the returned map will update this table. The returned map does not support put() or putAll(), or setValue() on its entries.

In contrast, the maps returned by columnMap().get() have the same behavior as those returned by column(C). Those maps may support setValue(), put(), and putAll().

Returns:

a map view from each column key to a secondary map from row keys to values