com.kabira.platform

Class QueryScope

java.lang.Object

com.kabira.platform.QueryScope

public final class QueryScope
extends java.lang.Object

Class used to define a set of remote nodes used for distributed queries.

This class allows applications to define queries that are done on a subset of nodes in the cluster.

When a query is executed using a user defined query scope, the current audit mode is used to verify the scope. If the default QueryScope.AuditMode.AUDIT_NODE_LIST audit mode is enabled, distributed queries are skipped if distribution is not active when the query is executed. If distribution is active, only those nodes that are active in the node list are used in the query, all other nodes are ignored. Otherwise, the auditing documented in the QueryScope.AuditMode enumeration is performed, and a ResourceUnavailableException exception is thrown if the audit fails.

When setAuditMode(AuditMode) is called, no audits are done at that time. Only when a query is executed is auditing done. This insures that auditing is performed before each execution of the query.

To support cluster wide queries, the QUERY_CLUSTER predefined instance of QueryScope can be used.

To disable node or cluster scoped queries, the QUERY_LOCAL predefined instance of QueryScope can be used.

See Also:

KeyQuery.setQueryScope(QueryScope), ManagedObject.extent(Class, QueryScope, LockMode), ManagedObject.cardinality(Class, QueryScope)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	QueryScope.AuditMode Possible audits that can be applied to the query.

Field Summary

Fields

Modifier and Type	Field and Description
static QueryScope	QUERY_CLUSTER The query will be done on all active nodes in the cluster.
static QueryScope	QUERY_LOCAL The query will be done only on the local node.

Constructor Summary

Constructors

Constructor and Description
QueryScope() Create a QueryScope instance with no nodes.
QueryScope(java.lang.String[] remoteNodes) Create a QueryScope instance

Method Summary

Modifier and Type	Method and Description
void	addNode(java.lang.String nodeName) Adds the specified node if not already present.
QueryScope.AuditMode	getAuditMode() Return the current audit mode.
java.lang.String[]	getNodes() Get the nodes defined for this query scope.
void	removeNode(java.lang.String nodeName) Removed the specified node.
void	setAuditMode(QueryScope.AuditMode auditMode) Set audit mode when queries are executed.

Methods inherited from class java.lang.Object

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

Field Detail

QUERY_LOCAL

public static final QueryScope QUERY_LOCAL

The query will be done only on the local node. This is the default scope.

QUERY_CLUSTER

public static final QueryScope QUERY_CLUSTER

The query will be done on all active nodes in the cluster.

Constructor Detail

QueryScope

public QueryScope()

Create a QueryScope instance with no nodes.

QueryScope

public QueryScope(java.lang.String[] remoteNodes)

Create a QueryScope instance

Parameters:

remoteNodes - Array of remote nodes.

Method Detail

addNode

public void addNode(java.lang.String nodeName)
             throws java.lang.UnsupportedOperationException

Adds the specified node if not already present.

Parameters:

nodeName - Node to add.

Throws:

java.lang.UnsupportedOperationException - The operation was called on QUERY_LOCAL or QUERY_CLUSTER.

removeNode

public void removeNode(java.lang.String nodeName)
                throws java.lang.UnsupportedOperationException

Removed the specified node. If not present, the remove is ignored.

Parameters:

nodeName - Node to remove.

Throws:

java.lang.UnsupportedOperationException - The operation was called on QUERY_LOCAL or QUERY_CLUSTER.

getNodes

public java.lang.String[] getNodes()

Get the nodes defined for this query scope.

If this method is called on QUERY_LOCAL or QUERY_CLUSTER instances, a zero length array is returned.

Returns:

Array of node names.

setAuditMode

public void setAuditMode(QueryScope.AuditMode auditMode)
                  throws java.lang.UnsupportedOperationException

Set audit mode when queries are executed.

Parameters:

auditMode - Audit mode to use.

Throws:

java.lang.UnsupportedOperationException - The operation was called on QUERY_LOCAL or QUERY_CLUSTER.

getAuditMode

public QueryScope.AuditMode getAuditMode()
                                  throws java.lang.UnsupportedOperationException

Return the current audit mode.

Returns:

Current audit mode.

Throws:

java.lang.UnsupportedOperationException - The operation was called on QUERY_LOCAL or QUERY_CLUSTER.