@GwtCompatible(serializable=true) public class TreeBasedTable<R,C,V> extends Object
Table whose row keys and column keys are ordered by their natural
ordering or by supplied comparators. When constructing a TreeBasedTable, you may provide
comparators for the row keys and the column keys, or you may use natural ordering for both.
The rowKeySet() method returns a SortedSet and the rowMap() method
returns a SortedMap, instead of the Set and Map specified by the Table interface.
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.
Because a TreeBasedTable has unique sorted values for a given row, both row(rowKey) and rowMap().get(rowKey) are SortedMap instances, instead of the
Map specified in the Table interface.
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.
|
Comparator<? super C> |
columnComparator()
Deprecated.
Store the
Comparator alongside the Table. Or, if you know that the
Table contains at least one value, you can retrieve the Comparator with:
((SortedMap<C, V>) table.rowMap().values().iterator().next()).comparator();. |
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(@Nullable Object rowKey,
@Nullable Object columnKey)
Returns
true if the table contains a mapping with the specified row and column keys. |
boolean |
containsColumn(@Nullable Object columnKey)
Returns
true if the table contains a mapping with the specified column. |
boolean |
containsRow(@Nullable Object rowKey)
Returns
true if the table contains a mapping with the specified row key. |
boolean |
containsValue(@Nullable Object value)
Returns
true if the table contains a mapping with the specified value. |
static <R extends Comparable,C extends Comparable,V> |
create()
Creates an empty
TreeBasedTable that uses the natural orderings of both row and column
keys. |
static <R,C,V> TreeBasedTable<R,C,V> |
create(Comparator<? super R> rowComparator,
Comparator<? super C> columnComparator)
Creates an empty
TreeBasedTable that is ordered by the specified comparators. |
static <R,C,V> TreeBasedTable<R,C,V> |
create(TreeBasedTable<R,C,? extends V> table)
Creates a
TreeBasedTable with the same mappings and sort order as the specified TreeBasedTable. |
boolean |
equals(@Nullable Object obj)
Indicates whether some other object is "equal to" this one.
|
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. |
int |
hashCode()
Returns a hash code value for the object.
|
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(@Nullable Object rowKey,
@Nullable Object columnKey)
Removes the mapping, if any, associated with the given keys.
|
SortedMap<C,V> |
row(R rowKey)
Returns a view of all mappings that have the given row key.
|
Comparator<? super R> |
rowComparator()
Deprecated.
Use
table.rowKeySet().comparator() instead. |
SortedSet<R> |
rowKeySet()
Returns a set of row keys that have one or more values in the table.
|
SortedMap<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.
|
clone, finalize, getClass, notify, notifyAll, wait, wait, waitcellSet, clear, column, columnKeySet, columnMap, contains, containsColumn, containsRow, containsValue, equals, get, hashCode, isEmpty, put, putAll, remove, size, valuespublic static <R extends Comparable,C extends Comparable,V> TreeBasedTable<R,C,V> create()
TreeBasedTable that uses the natural orderings of both row and column
keys.
The method signature specifies R extends Comparable with a raw Comparable,
instead of R extends Comparable<? super R>, and the same for C. That's
necessary to support classes defined without generics.
public static <R,C,V> TreeBasedTable<R,C,V> create(Comparator<? super R> rowComparator, Comparator<? super C> columnComparator)
TreeBasedTable that is ordered by the specified comparators.rowComparator - the comparator that orders the row keyscolumnComparator - the comparator that orders the column keyspublic static <R,C,V> TreeBasedTable<R,C,V> create(TreeBasedTable<R,C,? extends V> table)
TreeBasedTable with the same mappings and sort order as the specified TreeBasedTable.@Deprecated public Comparator<? super R> rowComparator()
table.rowKeySet().comparator() instead.Ordering.natural()
is returned.@Deprecated public Comparator<? super C> columnComparator()
Comparator alongside the Table. Or, if you know that the
Table contains at least one value, you can retrieve the Comparator with:
((SortedMap<C, V>) table.rowMap().values().iterator().next()).comparator();.Ordering.natural() is returned.public SortedMap<C,V> row(R rowKey)
Changes to the returned map will update the underlying table, and vice versa.
Because a TreeBasedTable has unique sorted values for a given row, this method
returns a SortedMap, instead of the Map specified in the Table
interface.
public SortedMap<R,Map<C,V>> rowMap()
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().
This method returns a SortedMap, instead of the Map specified in the Table interface.
public boolean contains(@Nullable Object rowKey, @Nullable Object columnKey)
Tabletrue if the table contains a mapping with the specified row and column keys.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 forpublic 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 forpublic 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 forpublic V get(@Nullable Object rowKey, @Nullable Object columnKey)
Tablenull if no such
mapping exists.public boolean isEmpty()
Tabletrue if the table contains no mappings.public int size()
Tablepublic void clear()
Table@CanIgnoreReturnValue public V put(R rowKey, C columnKey, V value)
Tableput 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 keys@CanIgnoreReturnValue public V remove(@Nullable Object rowKey, @Nullable Object columnKey)
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.
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<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.
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().
public 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.public boolean equals(@Nullable Object obj)
java.lang.Object
The equals method implements an equivalence relation
on non-null object references:
x, x.equals(x) should return
true.
x and y, x.equals(y)
should return true if and only if
y.equals(x) returns true.
x, y, and z, if
x.equals(y) returns true and
y.equals(z) returns true, then
x.equals(z) should return true.
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.
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.
public int hashCode()
java.lang.ObjectHashMap.
The general contract of hashCode is:
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.
equals(Object)
method, then calling the hashCode method on each of
the two objects must produce the same integer result.
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 hash tables.
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™ programming language.)
hashCode in interface Table<R,C,V>hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)Copyright © 2010–2019. All rights reserved.