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java.lang.Objectcom.google.common.collect.HashBasedTable<R,C,V>
@GwtCompatible(serializable=true) @Beta public class HashBasedTable<R,C,V>
Implementation of 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.
| Nested Class Summary |
|---|
| Nested classes/interfaces inherited from interface com.google.common.collect.Table |
|---|
Table.Cell<R,C,V> |
| Method Summary | ||
|---|---|---|
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
|
create()
Creates an empty HashBasedTable. |
|
static
|
create(int expectedRows,
int expectedCellsPerRow)
Creates an empty HashBasedTable with the specified map sizes. |
|
static
|
create(Table<? extends R,? extends C,? extends V> table)
Creates a HashBasedTable with the same mappings as the specified
table. |
|
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. |
|
String |
toString()
Returns the string representation rowMap().toString(). |
|
Collection<V> |
values()
Returns a collection of all values, which may contain duplicates. |
|
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Method Detail |
|---|
public static <R,C,V> HashBasedTable<R,C,V> create()
HashBasedTable.
public static <R,C,V> HashBasedTable<R,C,V> create(int expectedRows,
int expectedCellsPerRow)
HashBasedTable with the specified map sizes.
expectedRows - the expected number of distinct row keysexpectedCellsPerRow - the expected number of column key / value
mappings in each row
IllegalArgumentException - if expectedRows or expectedCellsPerRow is negativepublic static <R,C,V> HashBasedTable<R,C,V> create(Table<? extends R,? extends C,? extends V> table)
HashBasedTable with the same mappings as the specified
table.
table - the table to copy
NullPointerException - if any of the row keys, column keys, or values
in table is null
public boolean contains(@Nullable
Object rowKey,
@Nullable
Object columnKey)
Tabletrue if the table contains a mapping with the specified
row and column keys.
contains in interface Table<R,C,V>rowKey - key of row to search forcolumnKey - key of column to search for
public boolean containsColumn(@Nullable
Object columnKey)
Tabletrue if the table contains a mapping with the specified
column.
containsColumn in interface Table<R,C,V>columnKey - key of column to search for
public boolean containsRow(@Nullable
Object rowKey)
Tabletrue if the table contains a mapping with the specified
row key.
containsRow in interface Table<R,C,V>rowKey - key of row to search for
public boolean containsValue(@Nullable
Object value)
Tabletrue if the table contains a mapping with the specified
value.
containsValue in interface Table<R,C,V>value - value to search for
public V get(@Nullable
Object rowKey,
@Nullable
Object columnKey)
Tablenull if no such mapping exists.
get in interface Table<R,C,V>rowKey - key of row to search forcolumnKey - key of column to search for
public boolean equals(@Nullable
Object obj)
TableTable.cellSet(), are equal.
equals in interface Table<R,C,V>
public V remove(@Nullable
Object rowKey,
@Nullable
Object columnKey)
Table
remove in interface Table<R,C,V>rowKey - row key of mapping to be removedcolumnKey - column key of mapping to be removed
null if
no such value existedpublic boolean isEmpty()
Tabletrue if the table contains no mappings.
isEmpty in interface Table<R,C,V>public int size()
Table
size in interface Table<R,C,V>public int hashCode()
TableTable.cellSet().
hashCode in interface Table<R,C,V>hashCode in class Objectpublic String toString()
rowMap().toString().
toString in class Objectpublic void clear()
Table
clear in interface Table<R,C,V>
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 keys
null if
no mapping existed for the keyspublic void putAll(Table<? extends R,? extends C,? extends V> table)
TableTable.put(R, C, V) with each row key / column key / value
mapping in table.
putAll in interface Table<R,C,V>table - the table to add to this tablepublic 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.
cellSet in interface Table<R,C,V>public Map<C,V> row(R rowKey)
TableChanges to the returned map will update the underlying table, and vice versa.
row in interface Table<R,C,V>rowKey - key of row to search for in the table
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().
column in interface Table<R,C,V>columnKey - key of column to search for in the table
public Set<R> rowKeySet()
Table
rowKeySet in interface Table<R,C,V>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 Collection<V> values()
The collection's iterator traverses the values for the first row, the values for the second row, and so on.
values in interface Table<R,C,V>public Map<R,Map<C,V>> rowMap()
Tableput() 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().
rowMap in interface Table<R,C,V>public Map<C,Map<R,V>> columnMap()
Tableput() 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().
columnMap in interface Table<R,C,V>
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