public class HashBasedTable<R,C,V> extends Object
Table
using hash tables.
The views returned by column(C)
, columnKeySet()
, and columnMap()
have iterators that don't support remove()
. Otherwise,
all optional operations are supported. Null row keys, columns keys, and
values are not supported.
Lookups by row key are often faster than lookups by column key, because
the data is stored in a Map<R, Map<C, V>>
. A method call like column(columnKey).get(rowKey)
still runs quickly, since the row key is
provided. However, column(columnKey).size()
takes longer, since an
iteration across all row keys occurs.
Note that this implementation is not synchronized. If multiple threads access this table concurrently and one of the threads modifies the table, it must be synchronized externally.
See the Guava User Guide article on
Table
.
Table.Cell<R,C,V>
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. |
static <R,C,V> HashBasedTable<R,C,V> |
create()
Creates an empty
HashBasedTable . |
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.
|
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.
|
String |
toString()
Returns the string representation
rowMap().toString() . |
public static <R,C,V> HashBasedTable<R,C,V> create()
HashBasedTable
.public boolean contains(Object rowKey, Object columnKey)
Table
true
if the table contains a mapping with the specified
row and column keys.public boolean containsColumn(Object columnKey)
Table
true
if the table contains a mapping with the specified
column.containsColumn
in interface Table<R,C,V>
columnKey
- key of column to search forpublic boolean containsValue(Object value)
Table
true
if the table contains a mapping with the specified
value.containsValue
in interface Table<R,C,V>
value
- value to search forpublic V get(Object rowKey, Object columnKey)
Table
null
if no such mapping exists.public boolean equals(Object obj)
Table
Table.cellSet()
, are equal.public boolean containsRow(Object rowKey)
Table
true
if the table contains a mapping with the specified
row key.containsRow
in interface Table<R,C,V>
rowKey
- key of row to search forpublic int size()
Table
public void clear()
Table
public V put(R rowKey, C columnKey, V value)
Table
put
in interface Table<R,C,V>
rowKey
- row key that the value should be associated withcolumnKey
- column key that the value should be associated withvalue
- value to be associated with the specified keysnull
if
no mapping existed for the keyspublic V remove(Object rowKey, Object columnKey)
Table
public Set<Table.Cell<R,C,V>> cellSet()
add
or addAll
methods.
The set's iterator traverses the mappings for the first row, the mappings for the second row, and so on.
Each cell is an immutable snapshot of a row key / column key / value mapping, taken at the time the cell is returned by a method call to the set or its iterator.
public Map<C,V> row(R rowKey)
Table
Changes to the returned map will update the underlying table, and vice versa.
public Map<R,V> column(C columnKey)
Changes to the returned map will update the underlying table, and vice versa.
The returned map's views have iterators that don't support
remove()
.
public Set<R> rowKeySet()
Table
public Set<C> columnKeySet()
The returned set has an iterator that does not support remove()
.
The set's iterator traverses the columns of the first row, the columns of the second row, etc., skipping any columns that have appeared previously.
columnKeySet
in interface Table<R,C,V>
public Map<R,Map<C,V>> rowMap()
Table
put()
or putAll()
, or
setValue()
on its entries.
In contrast, the maps returned by rowMap().get()
have the same
behavior as those returned by Table.row(R)
. Those maps may support setValue()
, put()
, and putAll()
.
public Map<C,Map<R,V>> columnMap()
Table
put()
or putAll()
,
or setValue()
on its entries.
In contrast, the maps returned by columnMap().get()
have the
same behavior as those returned by Table.column(C)
. Those maps may support
setValue()
, put()
, and putAll()
.
public void putAll(Table<? extends R,? extends C,? extends V> table)
Table
Table.put(R, C, V)
with each row key / column key / value
mapping in table
.public int hashCode()
Table
Table.cellSet()
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