Package com.google.common.collect

Class TreeBasedTable<R,C,V>

  • All Implemented Interfaces:
    RowSortedTable<R,C,V>, Table<R,C,V>, Serializable
    @GwtCompatible(serializable=true)
public class TreeBasedTable<R,C,V>
extends Object
    Implementation of 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 Table.column(C), columnKeySet(), and Table.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.

    Since:
    7.0
    Author:
    Jared Levy, Louis Wasserman
    See Also:
    Serialized Form

    • Method Detail

      • create

        public static <R extends Comparable,C extends Comparable,V> TreeBasedTable<R,C,V> create()
        Creates an empty 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.

      • create

        public 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.
        Parameters:
        rowComparator - the comparator that orders the row keys
        columnComparator - the comparator that orders the column keys

      • create

        public 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.

      • row

        public SortedMap<C,V> row(R rowKey)
        Returns a view of all mappings that have the given row key. For each row key / column key / value mapping in the table with that row key, the returned map associates the column key with the value. If no mappings in the table have the provided row key, an empty map is returned.

        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.

        Specified by:
        row in interface Table<R,C,V>
        Parameters:
        rowKey - key of row to search for in the table
        Returns:
        the corresponding map from column keys to values
        Since:
        10.0 (mostly source-compatible since 7.0)

      • rowKeySet

        public SortedSet<R> rowKeySet()
        Returns a set of row keys that have one or more values in the table. Changes to the set will update the underlying table, and vice versa.

        This method returns a SortedSet, instead of the Set specified in the Table interface.

        Specified by:
        rowKeySet in interface RowSortedTable<R,C,V>
        Specified by:
        rowKeySet in interface Table<R,C,V>
        Returns:
        set of row keys

      • rowMap

        public SortedMap<R,Map<C,V>> rowMap()
        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().

        This method returns a SortedMap, instead of the Map specified in the Table interface.

        Specified by:
        rowMap in interface RowSortedTable<R,C,V>
        Specified by:
        rowMap in interface Table<R,C,V>
        Returns:
        a map view from each row key to a secondary map from column keys to values

      • contains

        public boolean contains(@Nullable Object rowKey,
                        @Nullable 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>
        Parameters:
        rowKey - key of row to search for
        columnKey - key of column to search for

      • containsColumn

        public boolean containsColumn(@Nullable 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>
        Parameters:
        columnKey - key of column to search for

      • containsRow

        public boolean containsRow(@Nullable 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>
        Parameters:
        rowKey - key of row to search for

      • containsValue

        public boolean containsValue(@Nullable 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>
        Parameters:
        value - value to search for

      • get

        public V get(@Nullable Object rowKey,
             @Nullable 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>
        Parameters:
        rowKey - key of row to search for
        columnKey - key of column to search for

      • isEmpty

        public boolean isEmpty()
        Description copied from interface: Table
        Returns true if the table contains no mappings.
        Specified by:
        isEmpty in interface Table<R,C,V>

      • size

        public int size()
        Description copied from interface: Table
        Returns the number of row key / column key / value mappings in the table.
        Specified by:
        size in interface Table<R,C,V>

      • clear

        public void clear()
        Description copied from interface: Table
        Removes all mappings from the table.
        Specified by:
        clear in interface Table<R,C,V>

      • put

        @CanIgnoreReturnValue
public V put(R rowKey,
             C columnKey,
             V value)
        Description copied from interface: Table
        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.
        Specified by:
        put in interface Table<R,C,V>
        Parameters:
        rowKey - row key that the value should be associated with
        columnKey - column key that the value should be associated with
        value - value to be associated with the specified keys
        Returns:
        the value previously associated with the keys, or null if no mapping existed for the keys

      • remove

        @CanIgnoreReturnValue
public V remove(@Nullable Object rowKey,
                @Nullable 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>
        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

      • cellSet

        public Set<Table.Cell<R,C,V>> cellSet()
        Returns a set of all row key / column key / value triplets. Changes to the returned set will update the underlying table, and vice versa. The cell set does not support the 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.

        Specified by:
        cellSet in interface Table<R,C,V>
        Returns:
        set of table cells consisting of row key / column key / value triplets

      • column

        public Map<R,V> column(C columnKey)
        Returns a view of all mappings that have the given column key. For each row key / column key / value mapping in the table with that column key, the returned map associates the row key with the value. If no mappings in the table have the provided column key, an empty map is returned.

        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().

        Specified by:
        column in interface Table<R,C,V>
        Parameters:
        columnKey - key of column to search for in the table
        Returns:
        the corresponding map from row keys to values

      • columnKeySet

        public Set<C> columnKeySet()
        Returns a set of column keys that have one or more values in the table. Changes to the set will update the underlying table, and vice versa.

        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.

        Specified by:
        columnKeySet in interface Table<R,C,V>
        Returns:
        set of column keys

      • values

        public Collection<V> values()
        Returns a collection of all values, which may contain duplicates. Changes to the returned collection will update the underlying table, and vice versa.

        The collection's iterator traverses the values for the first row, the values for the second row, and so on.

        Specified by:
        values in interface Table<R,C,V>
        Returns:
        collection of values

      • columnMap

        public Map<C,Map<R,V>> columnMap()
        Description copied from interface: 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().

        Specified by:
        columnMap in interface Table<R,C,V>
        Returns:
        a map view from each column key to a secondary map from row keys to values

      • putAll

        public void putAll(Table<? extends R,? extends C,? extends V> table)
        Description copied from interface: 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.
        Specified by:
        putAll in interface Table<R,C,V>
        Parameters:
        table - the table to add to this table

      • equals

        public boolean equals(@Nullable Object obj)
        Description copied from class: java.lang.Object
        Indicates whether some other object is "equal to" this one.

        The equals method implements an equivalence relation on non-null object references:

        • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
        • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
        • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
        • It is consistent: for any non-null reference values 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.
        • For any non-null reference value 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.

        Specified by:
        equals in interface Table<R,C,V>
        Overrides:
        equals in class Object
        Parameters:
        obj - the reference object with which to compare.
        Returns:
        true if this object is the same as the obj argument; false otherwise.
        See Also:
        Object.hashCode(), HashMap

      • hashCode

        public int hashCode()
        Description copied from class: java.lang.Object
        Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

        The general contract of hashCode is:

        • Whenever it is invoked on the same object more than once during an execution of a Java application, the 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.
        • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
        • It is not required that if two objects are unequal according to the 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. (The hashCode may or may not be implemented as some function of an object's memory address at some point in time.)

        Specified by:
        hashCode in interface Table<R,C,V>
        Overrides:
        hashCode in class Object
        Returns:
        a hash code value for this object.
        See Also:
        Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

      • toString

        public String toString()
        Returns the string representation rowMap().toString().
        Overrides:
        toString in class Object
        Returns:
        a string representation of the object.