com.google.common.collect

Class HashBasedTable<R,C,V>

java.lang.Object

com.google.common.collect.AbstractTable<R,C,V>

com.google.common.collect.StandardTable<R,C,V>

com.google.common.collect.HashBasedTable<R,C,V>

All Implemented Interfaces:

Table<R,C,V>, java.io.Serializable

@GwtCompatible(serializable=true)
public class HashBasedTable<R,C,V>
extends StandardTable<R,C,V>

Implementation of Table using linked hash tables. This guarantees predictable iteration order of the various views.

The views returned by StandardTable.column(C), StandardTable.columnKeySet(), and StandardTable.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.

Since:

7.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	HashBasedTable.Factory<C,V>

Nested classes/interfaces inherited from class com.google.common.collect.StandardTable

StandardTable.Row, StandardTable.RowMap

Nested classes/interfaces inherited from class com.google.common.collect.AbstractTable

AbstractTable.CellSet, AbstractTable.Values

Nested classes/interfaces inherited from interface com.google.common.collect.Table

Table.Cell<R,C,V>

Field Summary

Fields

Modifier and Type	Field and Description
private static long	serialVersionUID

Fields inherited from class com.google.common.collect.StandardTable

backingMap, factory

Constructor Summary

Constructors

Constructor and Description
HashBasedTable(java.util.Map<R,java.util.Map<C,V>> backingMap, HashBasedTable.Factory<C,V> factory)

Method Summary

Modifier and Type	Method and Description
boolean	contains(java.lang.Object rowKey, java.lang.Object columnKey) Returns true if the table contains a mapping with the specified row and column keys.
boolean	containsColumn(java.lang.Object columnKey) Returns true if the table contains a mapping with the specified column.
boolean	containsRow(java.lang.Object rowKey) Returns true if the table contains a mapping with the specified row key.
boolean	containsValue(java.lang.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.
static <R,C,V> HashBasedTable<R,C,V>	create(int expectedRows, int expectedCellsPerRow) Creates an empty HashBasedTable with the specified map sizes.
static <R,C,V> HashBasedTable<R,C,V>	create(Table<? extends R,? extends C,? extends V> table) Creates a HashBasedTable with the same mappings as the specified table.
boolean	equals(java.lang.Object obj) Compares the specified object with this table for equality.
V	get(java.lang.Object rowKey, java.lang.Object columnKey) Returns the value corresponding to the given row and column keys, or null if no such mapping exists.
V	remove(java.lang.Object rowKey, java.lang.Object columnKey) Removes the mapping, if any, associated with the given keys.

Methods inherited from class com.google.common.collect.StandardTable

cellIterator, cellSet, cellSpliterator, clear, column, columnKeySet, columnMap, createColumnKeyIterator, createRowMap, isEmpty, put, row, rowKeySet, rowMap, size, values

Methods inherited from class com.google.common.collect.AbstractTable

createCellSet, createValues, hashCode, putAll, toString, valuesIterator, valuesSpliterator

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

Constructor Detail

HashBasedTable

HashBasedTable(java.util.Map<R,java.util.Map<C,V>> backingMap,
               HashBasedTable.Factory<C,V> factory)

Method Detail

create

public static <R,C,V> HashBasedTable<R,C,V> create()

Creates an empty HashBasedTable.

create

public static <R,C,V> HashBasedTable<R,C,V> create(int expectedRows,
                                                   int expectedCellsPerRow)

Creates an empty HashBasedTable with the specified map sizes.

Parameters:

expectedRows - the expected number of distinct row keys

expectedCellsPerRow - the expected number of column key / value mappings in each row

Throws:

java.lang.IllegalArgumentException - if expectedRows or expectedCellsPerRow is negative

create

public static <R,C,V> HashBasedTable<R,C,V> create(Table<? extends R,? extends C,? extends V> table)

Creates a HashBasedTable with the same mappings as the specified table.

Parameters:

table - the table to copy

Throws:

java.lang.NullPointerException - if any of the row keys, column keys, or values in table is null

contains

public boolean contains(java.lang.Object rowKey,
                        java.lang.Object columnKey)

Description copied from interface: Table

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

Specified by:

contains in interface Table<R,C,V>

Overrides:

contains in class StandardTable<R,C,V>

Parameters:

rowKey - key of row to search for

columnKey - key of column to search for

containsColumn

public boolean containsColumn(java.lang.Object columnKey)

Description copied from interface: Table

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

Specified by:

containsColumn in interface Table<R,C,V>

Overrides:

containsColumn in class StandardTable<R,C,V>

Parameters:

columnKey - key of column to search for

containsRow

public boolean containsRow(java.lang.Object rowKey)

Description copied from interface: Table

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

Specified by:

containsRow in interface Table<R,C,V>

Overrides:

containsRow in class StandardTable<R,C,V>

Parameters:

rowKey - key of row to search for

containsValue

public boolean containsValue(java.lang.Object value)

Description copied from interface: Table

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

Specified by:

containsValue in interface Table<R,C,V>

Overrides:

containsValue in class StandardTable<R,C,V>

Parameters:

value - value to search for

get

public V get(java.lang.Object rowKey,
             java.lang.Object columnKey)

Description copied from interface: Table

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

Specified by:

get in interface Table<R,C,V>

Overrides:

get in class StandardTable<R,C,V>

Parameters:

rowKey - key of row to search for

columnKey - key of column to search for

equals

public boolean equals(java.lang.Object obj)

Description copied from interface: 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.

Specified by:

equals in interface Table<R,C,V>

Overrides:

equals in class AbstractTable<R,C,V>

remove

public V remove(java.lang.Object rowKey,
                java.lang.Object columnKey)

Description copied from interface: Table

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

Specified by:

remove in interface Table<R,C,V>

Overrides:

remove in class StandardTable<R,C,V>

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