@Beta @GwtCompatible(emulated=true) public final class ArrayTable<R,C,V> extends Object implements Serializable
Fixed-size Table
implementation backed by a two-dimensional array.
The allowed row and column keys must be supplied when the table is created. The table always contains a mapping for every row key / column pair. The value corresponding to a given row and column is null unless another value is provided.
The table’s size is constant: the product of the number of supplied row keys and the number of supplied column keys. The remove
and clear
methods are not supported by the table or its views. The erase(java.lang.Object, java.lang.Object)
and eraseAll()
methods may be used instead.
The ordering of the row and column keys provided when the table is constructed determines the iteration ordering across rows and columns in the table’s views. None of the view iterators support Iterator.remove()
. If the table is modified after an iterator is created, the iterator remains valid.
This class requires less memory than the HashBasedTable
and TreeBasedTable
implementations, except when the table is sparse.
Null row keys or column keys are not permitted.
This class provides methods involving the underlying array structure, where the array indices correspond to the position of a row or column in the lists of allowed keys and values. See the at(int, int)
, set(int, int, V)
, toArray(java.lang.Class<V>)
, rowKeyList()
, and columnKeyList()
methods for more details.
Note that this implementation is not synchronized. If multiple threads access the same cell of an ArrayTable
concurrently and one of the threads modifies its value, there is no guarantee that the new value will be fully visible to the other threads. To guarantee that modifications are visible, synchronize access to the table. Unlike other Table
implementations, synchronization is unnecessary between a thread that writes to one cell and a thread that reads from another.
See the Guava User Guide article on Table
.
Table.Cell<R,C,V>
Modifier and Type | Method and Description |
---|---|
V |
at(int rowIndex,
int columnIndex)
Returns the value corresponding to the specified row and column indices.
|
Set<Table.Cell<R,C,V>> |
cellSet()
Returns an unmodifiable set of all row key / column key / value triplets.
|
void |
clear()
Deprecated.
Use
eraseAll() |
Map<R,V> |
column(C columnKey)
Returns a view of all mappings that have the given column key.
|
ImmutableList<C> |
columnKeyList()
Returns, as an immutable list, the column keys provided when the table was constructed, including those that are mapped to null values only.
|
ImmutableSet<C> |
columnKeySet()
Returns an immutable set of the valid column keys, including those that are associated with null values only.
|
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 provided keys are among the keys provided when the table was constructed. |
boolean |
containsColumn(Object columnKey)
Returns
true if the provided column key is among the column keys provided when the table was constructed. |
boolean |
containsRow(Object rowKey)
Returns
true if the provided row key is among the row keys provided when the table was constructed. |
boolean |
containsValue(Object value)
Returns
true if the table contains a mapping with the specified value. |
static <R,C,V> ArrayTable<R,C,V> |
create(Iterable<? extends R> rowKeys,
Iterable<? extends C> columnKeys)
Creates an empty
ArrayTable . |
static <R,C,V> ArrayTable<R,C,V> |
create(Table<R,C,V> table)
Creates an
ArrayTable with the mappings in the provided table. |
boolean |
equals(Object obj)
Compares the specified object with this table for equality.
|
V |
erase(Object rowKey,
Object columnKey)
Associates the value
null with the specified keys, assuming both keys are valid. |
void |
eraseAll()
Associates the value
null with every pair of allowed row and column keys. |
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()
Always returns
false . |
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)
Deprecated.
|
Map<C,V> |
row(R rowKey)
Returns a view of all mappings that have the given row key.
|
ImmutableList<R> |
rowKeyList()
Returns, as an immutable list, the row keys provided when the table was constructed, including those that are mapped to null values only.
|
ImmutableSet<R> |
rowKeySet()
Returns an immutable set of the valid row keys, including those that are associated with null values only.
|
Map<R,Map<C,V>> |
rowMap()
Returns a view that associates each row key with the corresponding map from column keys to values.
|
V |
set(int rowIndex,
int columnIndex,
V value)
Associates
value with the specified row and column indices. |
int |
size()
Returns the number of row key / column key / value mappings in the table.
|
V[][] |
toArray(Class<V> valueClass)
Returns a two-dimensional array with the table contents.
|
String |
toString()
Returns the string representation
rowMap().toString() . |
Collection<V> |
values()
Returns an unmodifiable collection of all values, which may contain duplicates.
|
public static <R,C,V> ArrayTable<R,C,V> create(Iterable<? extends R> rowKeys, Iterable<? extends C> columnKeys)
Creates an empty ArrayTable
.
rowKeys
- row keys that may be stored in the generated tablecolumnKeys
- column keys that may be stored in the generated tableNullPointerException
- if any of the provided keys is nullIllegalArgumentException
- if rowKeys
or columnKeys
contains duplicates or is emptypublic static <R,C,V> ArrayTable<R,C,V> create(Table<R,C,V> table)
Creates an ArrayTable
with the mappings in the provided table.
If table
includes a mapping with row key r
and a separate mapping with column key c
, the returned table contains a mapping with row key r
and column key c
. If that row key / column key pair in not in table
, the pair maps to null
in the generated table.
The returned table allows subsequent put
calls with the row keys in table.rowKeySet()
and the column keys in table.columnKeySet()
. Calling put(R, C, V)
with other keys leads to an IllegalArgumentException
.
The ordering of table.rowKeySet()
and table.columnKeySet()
determines the row and column iteration ordering of the returned table.
NullPointerException
- if table
has a null keyIllegalArgumentException
- if the provided table is emptypublic ImmutableList<R> rowKeyList()
Returns, as an immutable list, the row keys provided when the table was constructed, including those that are mapped to null values only.
public ImmutableList<C> columnKeyList()
Returns, as an immutable list, the column keys provided when the table was constructed, including those that are mapped to null values only.
public V at(int rowIndex, int columnIndex)
Returns the value corresponding to the specified row and column indices. The same value is returned by get(rowKeyList().get(rowIndex), columnKeyList().get(columnIndex))
, but this method runs more quickly.
rowIndex
- position of the row key in rowKeyList()
columnIndex
- position of the row key in columnKeyList()
IndexOutOfBoundsException
- if either index is negative, rowIndex
is greater then or equal to the number of allowed row keys, or columnIndex
is greater then or equal to the number of allowed column keyspublic V set(int rowIndex, int columnIndex, @Nullable V value)
Associates value
with the specified row and column indices. The logic put(rowKeyList().get(rowIndex), columnKeyList().get(columnIndex), value)
has the same behavior, but this method runs more quickly.
rowIndex
- position of the row key in rowKeyList()
columnIndex
- position of the row key in columnKeyList()
value
- value to store in the tableIndexOutOfBoundsException
- if either index is negative, rowIndex
is greater then or equal to the number of allowed row keys, or columnIndex
is greater then or equal to the number of allowed column keys@GwtIncompatible(value="reflection") public V[][] toArray(Class<V> valueClass)
Returns a two-dimensional array with the table contents. The row and column indices correspond to the positions of the row and column in the iterables provided during table construction. If the table lacks a mapping for a given row and column, the corresponding array element is null.
Subsequent table changes will not modify the array, and vice versa.
valueClass
- class of values stored in the returned array@Deprecated public void clear()
eraseAll()
Not supported. Use eraseAll()
instead.
public void eraseAll()
Associates the value null
with every pair of allowed row and column keys.
public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey)
Returns true
if the provided keys are among the keys provided when the table was constructed.
public boolean containsColumn(@Nullable Object columnKey)
Returns true
if the provided column key is among the column keys provided when the table was constructed.
containsColumn
in interface Table<R,C,V>
columnKey
- key of column to search forpublic boolean containsRow(@Nullable Object rowKey)
Returns true
if the provided row key is among the row keys provided when the table was constructed.
containsRow
in interface Table<R,C,V>
rowKey
- key of row to search forpublic boolean containsValue(@Nullable Object value)
Table
Returns 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(@Nullable Object rowKey, @Nullable Object columnKey)
Table
Returns the value corresponding to the given row and column keys, or null
if no such mapping exists.
public boolean isEmpty()
Always returns false
.
public V put(R rowKey, C columnKey, @Nullable 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.
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 keysIllegalArgumentException
- if rowKey
is not in rowKeySet()
or columnKey
is not in columnKeySet()
.public 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 Table.put(R, C, V)
with each row key / column key / value mapping in table
.
If table
is an ArrayTable
, its null values will be stored in this table, possibly replacing values that were previously non-null.
putAll
in interface Table<R,C,V>
table
- the table to add to this tableNullPointerException
- if table
has a null keyIllegalArgumentException
- if any of the provided table’s row keys or column keys is not in rowKeySet()
or columnKeySet()
@Deprecated public V remove(Object rowKey, Object columnKey)
erase(java.lang.Object, java.lang.Object)
Not supported. Use erase(java.lang.Object, java.lang.Object)
instead.
public V erase(@Nullable Object rowKey, @Nullable Object columnKey)
Associates the value null
with the specified keys, assuming both keys are valid. If either key is null or isn’t among the keys provided during construction, this method has no effect.
This method is equivalent to put(rowKey, columnKey, null)
when both provided keys are valid.
rowKey
- row key of mapping to be erasedcolumnKey
- column key of mapping to be erasednull
if no mapping existed for the keyspublic int size()
Table
Returns the number of row key / column key / value mappings in the table.
public Set<Table.Cell<R,C,V>> cellSet()
Returns an unmodifiable set of all row key / column key / value triplets. Changes to the table will update the returned set.
The returned set’s iterator traverses the mappings with the first row key, the mappings with the second row key, and so on.
The value in the returned cells may change if the table subsequently changes.
public Map<R,V> column(C columnKey)
Returns a view of all mappings that have the given column key. If the column key isn’t in columnKeySet()
, an empty immutable map is returned.
Otherwise, for each row key in rowKeySet()
, the returned map associates the row key with the corresponding value in the table. Changes to the returned map will update the underlying table, and vice versa.
public ImmutableSet<C> columnKeySet()
Returns an immutable set of the valid column keys, including those that are associated with null values only.
columnKeySet
in interface Table<R,C,V>
public Map<C,Map<R,V>> columnMap()
Table
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 Table.column(C)
. Those maps may support setValue()
, put()
, and putAll()
.
public Map<C,V> row(R rowKey)
Returns a view of all mappings that have the given row key. If the row key isn’t in rowKeySet()
, an empty immutable map is returned.
Otherwise, for each column key in columnKeySet()
, the returned map associates the column key with the corresponding value in the table. Changes to the returned map will update the underlying table, and vice versa.
public ImmutableSet<R> rowKeySet()
Returns an immutable set of the valid row keys, including those that are associated with null values only.
public Map<R,Map<C,V>> rowMap()
Table
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 Table.row(R)
. Those maps may support setValue()
, put()
, and putAll()
.
public Collection<V> values()
Returns an unmodifiable collection of all values, which may contain duplicates. Changes to the table will update the returned collection.
The returned collection’s iterator traverses the values of the first row key, the values of the second row key, and so on.
public boolean equals(@Nullable Object obj)
Table
Compares the specified object with this table for equality. Two tables are equal when their cell views, as returned by Table.cellSet()
, are equal.
public int hashCode()
Table
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 Table.cellSet()
.