com.google.cloud.spanner

Class KeyRange

java.lang.Object

com.google.cloud.spanner.KeyRange

All Implemented Interfaces:

Serializable

public final class KeyRange
extends Object
implements Serializable

Represents a range of rows in a table or index.

A range has a start key and an end key. These keys can be open or closed, indicating if the range includes rows with that key.

For example, consider the following table definition:

     CREATE TABLE UserEvents (
       UserName STRING(MAX),
       EventDate STRING(10),
     ) PRIMARY KEY(UserName, EventDate);
 

The following keys name rows in this table:

• Key.of("Bob", "2014-09-23")
• Key.of("Alfred", "2015-06-12")

Since the UserEvents table's PRIMARY KEY clause names two columns, each UserEvents key has two elements; the first is the UserName, and the second is the EventDate.

Key ranges with multiple components are interpreted lexicographically by component using the table or index key's declared sort order. For example, the following range returns all events for user "Bob" that occurred in the year 2015:

     KeyRange.closedClosed(
         Key.of("Bob", "2015-01-01"),
         Key.of("Bob", "2015-12-31"))
 

Start and end keys can omit trailing key components. This affects the inclusion and exclusion of rows that exactly match the provided key components: if the key is closed, then rows that exactly match the provided components are included; if the key is open, then rows that exactly match are not included.

For example, the following range includes all events for "Bob" that occurred during and after the year 2000:

     KeyRange.closedClosed(
         Key.of("Bob", "2000-01-01"),
         Key.of("Bob"))
 

The next example retrieves all events for "Bob":

     KeyRange.prefix(Key.of("Bob"))
 

To retrieve events before the year 2000:

     KeyRange.closedOpen(
         Key.of("Bob"),
         Key.of("Bob", "2000-01-01"))
 

The following range includes all rows in the table:

     KeyRange.all()
 

This range returns all users whose UserName begins with any character from A to C:

     KeyRange.closedOpen(Key.of("A"), Key.of("D"))
 

This range returns all users whose UserName begins with B:

     KeyRange.closedOpen(Key.of("B"), Key.of("C"))
 

Key ranges honor column sort order. For example, suppose a table is defined as follows:

     CREATE TABLE DescendingSortedTable {
       Key INT64,
       ...
     ) PRIMARY KEY(Key DESC);
 

The following range retrieves all rows with key values between 1 and 100 inclusive:

     KeyRange.closedClosed(Key.of(100), Key.of(1))
 

Note that 100 is passed as the start, and 1 is passed as the end, because Key is a descending column in the schema.

KeyRange instances are immutable.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	KeyRange.Builder Builder for KeyRange instances.
static class	KeyRange.Endpoint Defines whether a range includes or excludes its endpoint keys.

Method Summary

Modifier and Type	Method and Description
static KeyRange	closedClosed(Key start, Key end) Returns a key range from start inclusive to end inclusive.
static KeyRange	closedOpen(Key start, Key end) Returns a key range from start inclusive to end exclusive.
boolean	equals(Object o)
KeyRange.Endpoint	geEndType() Indicates whether the end key is inclusive (CLOSED) or exclusive (OPEN).
Key	getEnd() Returns the end key of the range.
Key	getStart() Returns the start key of the range.
KeyRange.Endpoint	getStartType() Indicates whether the start key is inclusive (CLOSED) or exclusive (OPEN).
int	hashCode()
static KeyRange.Builder	newBuilder() Returns a new builder for constructing a range.
static KeyRange	openClosed(Key start, Key end) Returns a key range from start exclusive to end inclusive.
static KeyRange	openOpen(Key start, Key end) Returns a key range from start exclusive to end exclusive.
static KeyRange	prefix(Key prefix) Returns a key range that covers all keys where the first prefix.size() components match prefix exactly.
KeyRange.Builder	toBuilder() Returns a builder initialized with the value of this range.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

closedOpen

public static KeyRange closedOpen(Key start,
                                  Key end)

Returns a key range from start inclusive to end exclusive.

closedClosed

public static KeyRange closedClosed(Key start,
                                    Key end)

Returns a key range from start inclusive to end inclusive.

openOpen

public static KeyRange openOpen(Key start,
                                Key end)

Returns a key range from start exclusive to end exclusive.

openClosed

public static KeyRange openClosed(Key start,
                                  Key end)

Returns a key range from start exclusive to end inclusive.

prefix

public static KeyRange prefix(Key prefix)

Returns a key range that covers all keys where the first prefix.size() components match prefix exactly.

newBuilder

public static KeyRange.Builder newBuilder()

Returns a new builder for constructing a range.

getStart

public Key getStart()

Returns the start key of the range.

getStartType

public KeyRange.Endpoint getStartType()

Indicates whether the start key is inclusive (CLOSED) or exclusive (OPEN).

getEnd

public Key getEnd()

Returns the end key of the range.

geEndType

public KeyRange.Endpoint geEndType()

Indicates whether the end key is inclusive (CLOSED) or exclusive (OPEN).

toBuilder

public KeyRange.Builder toBuilder()

Returns a builder initialized with the value of this range.

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object