com.datastax.driver.core

Class SimpleStatement

java.lang.Object

com.datastax.driver.core.Statement

com.datastax.driver.core.RegularStatement

com.datastax.driver.core.SimpleStatement

public class SimpleStatement
extends RegularStatement

A simple RegularStatement implementation built directly from a query string.

Field Summary

Fields inherited from class com.datastax.driver.core.Statement

idempotent, NULL_PAYLOAD_VALUE

Constructor Summary

Constructors

Constructor and Description
SimpleStatement(String query) Creates a new SimpleStatement with the provided query string (and no values).
SimpleStatement(String query, Object... values) Creates a new SimpleStatement with the provided query string and values.

Method Summary

Modifier and Type	Method and Description
static ByteBuffer[]	convert(Object[] values, ProtocolVersion protocolVersion, CodecRegistry codecRegistry) Utility method to serialize user-provided values.
String	getKeyspace() Returns the keyspace this query operates on.
Object	getObject(int i) Returns the ith value as the Java type matching its CQL type.
String	getQueryString(CodecRegistry codecRegistry) Returns the query string for this statement.
ByteBuffer	getRoutingKey(ProtocolVersion protocolVersion, CodecRegistry codecRegistry) Returns the routing key for the query.
ByteBuffer[]	getValues(ProtocolVersion protocolVersion, CodecRegistry codecRegistry) The values to use for this statement.
boolean	hasValues(CodecRegistry codecRegistry) Whether or not this statement has values, that is if getValues will return null or not.
SimpleStatement	setKeyspace(String keyspace) Sets the keyspace this query operates on.
SimpleStatement	setRoutingKey(ByteBuffer... routingKeyComponents) Sets the routing key for this query.
SimpleStatement	setRoutingKey(ByteBuffer routingKey) Sets the routing key for this query.
int	valuesCount() The number of values for this statement, that is the size of the array that will be returned by getValues.

Methods inherited from class com.datastax.driver.core.RegularStatement

getQueryString, hasValues, toString

Methods inherited from class com.datastax.driver.core.Statement

disableTracing, enableTracing, getConsistencyLevel, getDefaultTimestamp, getFetchSize, getRetryPolicy, getSerialConsistencyLevel, isIdempotent, isTracing, setConsistencyLevel, setDefaultTimestamp, setFetchSize, setIdempotent, setOutgoingPayload, setPagingState, setPagingState, setPagingStateUnsafe, setRetryPolicy, setSerialConsistencyLevel

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SimpleStatement

public SimpleStatement(String query)

Creates a new SimpleStatement with the provided query string (and no values).

Parameters:

query - the query string.

SimpleStatement

public SimpleStatement(String query,
                       Object... values)

Creates a new SimpleStatement with the provided query string and values.

This version of SimpleStatement is useful when you want to execute a query only once (and thus do not want to resort to prepared statement), but do not want to convert all column values to string (typically, if you have blob values, encoding them to a hexadecimal string is not very efficient). In that case, you can provide a query string with bind markers to this constructor along with the values for those bind variables. When executed, the server will prepare the provided, bind the provided values to that prepare statement and execute the resulting statement. Thus,

   session.execute(new SimpleStatement(query, value1, value2, value3));
 

is functionally equivalent to

   PreparedStatement ps = session.prepare(query);
   session.execute(ps.bind(value1, value2, value3));
 

except that the former version:

• Requires only one round-trip to a Cassandra node.
• Does not left any prepared statement stored in memory (neither client or server side) once it has been executed.

Note that the type of the values provided to this method will not be validated by the driver as is done by BoundStatement.bind(java.lang.Object...) since query is not parsed (and hence the driver cannot know what those value should be). The codec to serialize each value will be chosen in the codec registry associated with this session's cluster, based on the value's Java type (this is the equivalent to calling CodecRegistry.codecFor(Object)). If too many or too few values are provided, or if a value is not a valid one for the variable it is bound to, an InvalidQueryException will be thrown by Cassandra at execution time. A CodecNotFoundException may be thrown by this constructor however, if the codec registry does not know how to handle one of the values.

Parameters:

query - the query string.

values - values required for the execution of query.

Throws:

IllegalArgumentException - if the number of values is greater than 65535.

Method Detail

getQueryString

public String getQueryString(CodecRegistry codecRegistry)

Description copied from class: RegularStatement

Returns the query string for this statement.

Specified by:

getQueryString in class RegularStatement

Parameters:

codecRegistry - the codec registry that will be used if the actual implementation needs to serialize Java objects in the process of generating the query. Note that it might be possible to use the no-arg RegularStatement.getQueryString() depending on the type of statement this is called on.

Returns:

a valid CQL query string.

See Also:

RegularStatement.getQueryString()

getValues

public ByteBuffer[] getValues(ProtocolVersion protocolVersion,
                              CodecRegistry codecRegistry)

Description copied from class: RegularStatement

The values to use for this statement.

Note: Values for a RegularStatement (i.e. if this method does not return null) are not supported with the native protocol version 1: you will get an UnsupportedProtocolVersionException when submitting one if version 1 of the protocol is in use (i.e. if you've force version 1 through Cluster.Builder.withProtocolVersion(com.datastax.driver.core.ProtocolVersion) or you use Cassandra 1.2).

Specified by:

getValues in class RegularStatement

Parameters:

protocolVersion - the protocol version that will be used to serialize the values.

codecRegistry - the codec registry that will be used to serialize the values.

See Also:

SimpleStatement(String, Object...)

valuesCount

public int valuesCount()

The number of values for this statement, that is the size of the array that will be returned by getValues.

Returns:

the number of values.

hasValues

public boolean hasValues(CodecRegistry codecRegistry)

Description copied from class: RegularStatement

Whether or not this statement has values, that is if getValues will return null or not.

Specified by:

hasValues in class RegularStatement

Parameters:

codecRegistry - the codec registry that will be used if the actual implementation needs to serialize Java objects in the process of determining if the query has values. Note that it might be possible to use the no-arg RegularStatement.hasValues() depending on the type of statement this is called on.

Returns:

false if RegularStatement.getValues(com.datastax.driver.core.ProtocolVersion, com.datastax.driver.core.CodecRegistry) returns null, true otherwise.

See Also:

RegularStatement.hasValues()

getObject

public Object getObject(int i)

Returns the ith value as the Java type matching its CQL type.

Parameters:

i - the index to retrieve.

Returns:

the value of the ith value of this statement.

Throws:

IllegalStateException - if this statement does not have values.

IndexOutOfBoundsException - if i is not a valid index for this object.

getRoutingKey

public ByteBuffer getRoutingKey(ProtocolVersion protocolVersion,
                                CodecRegistry codecRegistry)

Returns the routing key for the query.

Unless the routing key has been explicitly set through setRoutingKey(java.nio.ByteBuffer), this method will return null to avoid having to parse the query string to retrieve the partition key.

Specified by:

getRoutingKey in class Statement

Parameters:

protocolVersion - unused by this implementation (no internal serialization is required to compute the key).

codecRegistry - unused by this implementation (no internal serialization is required to compute the key).

Returns:

the routing key set through setRoutingKey(java.nio.ByteBuffer) if such a key was set, null otherwise.

See Also:

Statement.getRoutingKey(com.datastax.driver.core.ProtocolVersion, com.datastax.driver.core.CodecRegistry)

setRoutingKey

public SimpleStatement setRoutingKey(ByteBuffer routingKey)

Sets the routing key for this query.

This method allows you to manually provide a routing key for this query. It is thus optional since the routing key is only an hint for token aware load balancing policy but is never mandatory.

If the partition key for the query is composite, use the setRoutingKey(ByteBuffer...) method instead to build the routing key.

Parameters:

routingKey - the raw (binary) value to use as routing key.

Returns:

this SimpleStatement object.

See Also:

Statement.getRoutingKey(com.datastax.driver.core.ProtocolVersion, com.datastax.driver.core.CodecRegistry)

getKeyspace

public String getKeyspace()

Returns the keyspace this query operates on.

Unless the keyspace has been explicitly set through setKeyspace(java.lang.String), this method will return null to avoid having to parse the query string.

Specified by:

getKeyspace in class Statement

Returns:

the keyspace set through setKeyspace(java.lang.String) if such keyspace was set, null otherwise.

See Also:

Statement.getKeyspace()

setKeyspace

public SimpleStatement setKeyspace(String keyspace)

Sets the keyspace this query operates on.

This method allows you to manually provide a keyspace for this query. It is thus optional since the value returned by this method is only an hint for token aware load balancing policy but is never mandatory.

Do note that if the query does not use a fully qualified keyspace, then you do not need to set the keyspace through that method as the currently logged in keyspace will be used.

Parameters:

keyspace - the name of the keyspace this query operates on.

Returns:

this SimpleStatement object.

See Also:

Statement.getKeyspace()

setRoutingKey

public SimpleStatement setRoutingKey(ByteBuffer... routingKeyComponents)

Sets the routing key for this query.

See setRoutingKey(ByteBuffer) for more information. This method is a variant for when the query partition key is composite and thus the routing key must be built from multiple values.

Parameters:

routingKeyComponents - the raw (binary) values to compose to obtain the routing key.

Returns:

this SimpleStatement object.

See Also:

Statement.getRoutingKey(com.datastax.driver.core.ProtocolVersion, com.datastax.driver.core.CodecRegistry)

convert

public static ByteBuffer[] convert(Object[] values,
                                   ProtocolVersion protocolVersion,
                                   CodecRegistry codecRegistry)

Utility method to serialize user-provided values.

This method is useful in situations where there is no metadata available and the underlying CQL type for the values is not known.

This situation happens when a SimpleStatement or a BuiltStatement (Query Builder) contain values; in these places, the driver has no way to determine the right CQL type to use.

This method performs a best-effort heuristic to guess which codec to use. Note that this is not particularly efficient as the codec registry needs to iterate over the registered codecs until it finds a suitable one.

Parameters:

values - The values to convert.

protocolVersion - The protocol version to use.

codecRegistry - The CodecRegistry to use.

Returns:

The converted values.