org.modeshape.jcr.query

Class QueryContext

java.lang.Object

org.modeshape.jcr.query.QueryContext

@ThreadSafe
public class QueryContext
extends Object

An immutable context in which queries are to be executed. Each query context defines the information that is available during query execution.

The only mutable state on this context is whether the query has been cancelled.

Field Summary

Fields

Modifier and Type	Field and Description
protected BufferManager	bufferManager
protected ExecutionContext	context
protected PlanHints	hints
protected RepositoryIndexes	indexDefns
protected NodeTypes	nodeTypes
protected Map<String,NodeCache>	overriddenNodeCachesByWorkspaceName
protected Problems	problems
protected static AtomicLong	QUERY_COUNTER
protected RepositoryCache	repositoryCache
protected Schemata	schemata
protected TypeSystem	typeSystem
protected Map<String,Object>	variables
protected Set<String>	workspaceNames

Constructor Summary

Constructors

Modifier	Constructor and Description
	QueryContext(ExecutionContext context, RepositoryCache repositoryCache, Set<String> workspaceNames, Map<String,NodeCache> overriddenNodeCachesByWorkspaceName, Schemata schemata, RepositoryIndexes indexDefns, NodeTypes nodeTypes, BufferManager bufferManager, PlanHints hints, Problems problems, Map<String,Object> variables) Create a new context for query execution.
protected	QueryContext(ExecutionContext context, RepositoryCache repositoryCache, Set<String> workspaceNames, Map<String,NodeCache> overriddenNodeCachesByWorkspaceName, Schemata schemata, RepositoryIndexes indexDefns, NodeTypes nodeTypes, BufferManager bufferManager, PlanHints hints, Problems problems, Map<String,Object> variables, long id) Create a new context for query execution.
	QueryContext(ExecutionContext context, RepositoryCache repositoryCache, Set<String> workspaceNames, Schemata schemata, RepositoryIndexes indexDefns, NodeTypes nodeTypes, BufferManager bufferManager) Create a new context for query execution.
	QueryContext(ExecutionContext context, RepositoryCache repositoryCache, Set<String> workspaceNames, Schemata schemata, RepositoryIndexes indexDefns, NodeTypes nodeTypes, BufferManager bufferManager, PlanHints hints, Problems problems) Create a new context for query execution.
protected	QueryContext(QueryContext original) Create a new context that is a copy of the supplied context.

Method Summary

Modifier and Type	Method and Description
boolean	cancel() Cancel the query if it is currently running.
boolean	equals(Object obj)
BufferManager	getBufferManager()
ExecutionContext	getExecutionContext() Get the execution context in which the query is to be evaluated
PlanHints	getHints() Get the plan hints.
RepositoryIndexes	getIndexDefinitions() Get the current index definitions.
NamespaceRegistry	getNamespaceRegistry() Get the namespace registry with durable prefixes as used by the query indexes.
NodeCache	getNodeCache(String workspaceName) Get the NodeCache for the given workspace name.
NodeTypes	getNodeTypes() Get an immutable snapshot of the node types.
Problems	getProblems() Get the problem container used by this query context.
RepositoryCache	getRepositoryCache() Get the RepositoryCache instance that should be used to load the result tuple values.
Schemata	getSchemata() Get the definition of the tables available within this query context.
TypeSystem	getTypeSystem() Get the interface for working with literal values and types.
Map<String,Object>	getVariables() Get the variables that are to be substituted into the BindVariableName used in the query.
Set<String>	getWorkspaceNames() Get the names of each workspace that is to be queried.
int	hashCode()
long	id() Get the local identifier used within the query engine to identify a query context.
boolean	isCancelled()
QueryContext	with(Map<String,Object> variables) Obtain a copy of this context, except that the copy uses the supplied variables.
QueryContext	with(PlanHints hints) Obtain a copy of this context, except that the copy uses the supplied hints.
QueryContext	with(Problems problems) Obtain a copy of this context, except that the copy uses the supplied problem container.
QueryContext	with(Schemata schemata) Obtain a copy of this context, except that the copy uses the supplied schemata.

Methods inherited from class java.lang.Object

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

Field Detail

QUERY_COUNTER

protected static final AtomicLong QUERY_COUNTER

context

protected final ExecutionContext context

repositoryCache

protected final RepositoryCache repositoryCache

typeSystem

protected final TypeSystem typeSystem

hints

protected final PlanHints hints

nodeTypes

protected final NodeTypes nodeTypes

schemata

protected final Schemata schemata

indexDefns

protected final RepositoryIndexes indexDefns

problems

protected final Problems problems

variables

protected final Map<String,Object> variables

workspaceNames

protected final Set<String> workspaceNames

overriddenNodeCachesByWorkspaceName

protected final Map<String,NodeCache> overriddenNodeCachesByWorkspaceName

bufferManager

protected final BufferManager bufferManager

Constructor Detail

QueryContext

protected QueryContext(ExecutionContext context,
                       RepositoryCache repositoryCache,
                       Set<String> workspaceNames,
                       Map<String,NodeCache> overriddenNodeCachesByWorkspaceName,
                       Schemata schemata,
                       RepositoryIndexes indexDefns,
                       NodeTypes nodeTypes,
                       BufferManager bufferManager,
                       PlanHints hints,
                       Problems problems,
                       Map<String,Object> variables,
                       long id)

Create a new context for query execution.

Parameters:

context - the context in which the query is being executed; may not be null

repositoryCache - the repository cache that should be used to load results; may be null if no results are to be loaded

workspaceNames - the name of each workspace to be queried, or an empty set if all the workspaces should be queried; may not be null

overriddenNodeCachesByWorkspaceName - the NodeCache instances that should be used to load results, which will be used instead of the RepositoryCache's NodeCache for a given workspace name; may be null or empty

schemata - the schemata

indexDefns - the definitions for the currently-defined indexes; never null

nodeTypes - the snapshot of the node types; may not be null

bufferManager - the buffer manager; may not be null

hints - the hints, or null if there are no hints

problems - the problems container, or null if a new problems container should be created

variables - the mapping of variables and values, or null if there are no such variables

id - the identifier for this query context

Throws:

IllegalArgumentException - if the context, workspace name, or schemata are null

QueryContext

public QueryContext(ExecutionContext context,
                    RepositoryCache repositoryCache,
                    Set<String> workspaceNames,
                    Map<String,NodeCache> overriddenNodeCachesByWorkspaceName,
                    Schemata schemata,
                    RepositoryIndexes indexDefns,
                    NodeTypes nodeTypes,
                    BufferManager bufferManager,
                    PlanHints hints,
                    Problems problems,
                    Map<String,Object> variables)

Create a new context for query execution.

Parameters:

context - the context in which the query is being executed; may not be null

repositoryCache - the repository cache that should be used to load results; may be null if no results are to be loaded

workspaceNames - the name of each workspace to be queried, or an empty set if all the workspaces should be queried; may not be null

overriddenNodeCachesByWorkspaceName - the NodeCache instances that should be used to load results, which will be used instead of the RepositoryCache's NodeCache for a given workspace name; may be null or empty

schemata - the schemata

indexDefns - the definitions for the currently-defined indexes; never null

nodeTypes - the snapshot of the node types; may not be null

bufferManager - the buffer manager; may not be null

hints - the hints, or null if there are no hints

problems - the problems container, or null if a new problems container should be created

variables - the mapping of variables and values, or null if there are no such variables

Throws:

IllegalArgumentException - if the context, workspace name, or schemata are null

QueryContext

public QueryContext(ExecutionContext context,
                    RepositoryCache repositoryCache,
                    Set<String> workspaceNames,
                    Schemata schemata,
                    RepositoryIndexes indexDefns,
                    NodeTypes nodeTypes,
                    BufferManager bufferManager,
                    PlanHints hints,
                    Problems problems)

Create a new context for query execution.

Parameters:

context - the context in which the query is being executed; may not be null

repositoryCache - the repository cache that should be used to load results; may not be null

workspaceNames - the name of each workspace to be queried, or an empty set if all the workspaces should be queried; may not be null

schemata - the schemata

indexDefns - the definitions for the currently-defined indexes; never null

nodeTypes - the snapshot of the node types; may not be null

bufferManager - the buffer manager; may not be null

hints - the hints, or null if there are no hints

problems - the problems container, or null if a new problems container should be created

Throws:

IllegalArgumentException - if the context, workspace name, or schemata are null

QueryContext

public QueryContext(ExecutionContext context,
                    RepositoryCache repositoryCache,
                    Set<String> workspaceNames,
                    Schemata schemata,
                    RepositoryIndexes indexDefns,
                    NodeTypes nodeTypes,
                    BufferManager bufferManager)

Create a new context for query execution.

Parameters:

context - the context in which the query is being executed; may not be null

repositoryCache - the repository cache that should be used to load results; may not be null

workspaceNames - the name of each workspace to be queried, or an empty set if all the workspaces should be queried; may not be null

schemata - the schemata

indexDefns - the definitions for the currently-defined indexes; never null

nodeTypes - the snapshot of the node types; may not be null

bufferManager - the buffer manager; may not be null

Throws:

IllegalArgumentException - if the context, workspace name, or schemata are null

QueryContext

protected QueryContext(QueryContext original)

Create a new context that is a copy of the supplied context. This constructor is useful for subclasses that wish to add store additional fields in a QueryContext.

Parameters:

original - the original context

Throws:

IllegalArgumentException - if the original is null

Method Detail

cancel

public final boolean cancel()

Cancel the query if it is currently running. Note that this method does not block until the query is cancelled; it merely marks the query as being cancelled, and the query will terminate at its next available opportunity.

Returns:

true if the query was executing and will be cancelled, or false if the query was no longer running (because it had finished successfully or had already been cancelled) and could not be cancelled.

isCancelled

public final boolean isCancelled()

id

public final long id()

Get the local identifier used within the query engine to identify a query context. These identifiers are neither durable nor guaranteed to be unique over extended periods of time.

Returns:

the identifier

getNodeCache

public NodeCache getNodeCache(String workspaceName)
                       throws WorkspaceNotFoundException

Get the NodeCache for the given workspace name. The result will either be the overridden value supplied in the constructor or the workspace cache from the referenced RepositoryCache.

Parameters:

workspaceName - the name of the workspace

Returns:

the node cache; never null

Throws:

WorkspaceNotFoundException - if there is no workspace with the supplied name

getNamespaceRegistry

public NamespaceRegistry getNamespaceRegistry()

Get the namespace registry with durable prefixes as used by the query indexes.

Returns:

the durable namespace registry; never null

getRepositoryCache

public RepositoryCache getRepositoryCache()

Get the RepositoryCache instance that should be used to load the result tuple values.

Returns:

the node cache

getIndexDefinitions

public RepositoryIndexes getIndexDefinitions()

Get the current index definitions.

Returns:

the immutable index definitions; never null

getExecutionContext

public ExecutionContext getExecutionContext()

Get the execution context in which the query is to be evaluated

Returns:

the execution context; never null

getWorkspaceNames

public Set<String> getWorkspaceNames()

Get the names of each workspace that is to be queried.

Returns:

the workspace name; never null

getTypeSystem

public TypeSystem getTypeSystem()

Get the interface for working with literal values and types.

Returns:

the type system; never null

getHints

public final PlanHints getHints()

Get the plan hints.

Returns:

the plan hints; never null

getProblems

public final Problems getProblems()

Get the problem container used by this query context. Any problems that have been encountered will be accumlated in this container.

Returns:

the problem container; never null

getSchemata

public Schemata getSchemata()

Get the definition of the tables available within this query context.

Returns:

the schemata; never null

getNodeTypes

public NodeTypes getNodeTypes()

Get an immutable snapshot of the node types.

Returns:

the node types; never null

getBufferManager

public BufferManager getBufferManager()

getVariables

public Map<String,Object> getVariables()

Get the variables that are to be substituted into the BindVariableName used in the query.

Returns:

immutable map of variable values keyed by their name; never null but possibly empty

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

See Also:

Object.equals(java.lang.Object)

with

public QueryContext with(Schemata schemata)

Obtain a copy of this context, except that the copy uses the supplied schemata.

Parameters:

schemata - the schemata that should be used in the new context

Returns:

the new context; never null

Throws:

IllegalArgumentException - if the schemata reference is null

with

public QueryContext with(PlanHints hints)

Obtain a copy of this context, except that the copy uses the supplied hints.

Parameters:

hints - the hints that should be used in the new context

Returns:

the new context; never null

Throws:

IllegalArgumentException - if the hints reference is null

with

public QueryContext with(Problems problems)

Obtain a copy of this context, except that the copy uses the supplied problem container.

Parameters:

problems - the problems that should be used in the new context; may be null if a new problem container should be used

Returns:

the new context; never null

with

public QueryContext with(Map<String,Object> variables)

Obtain a copy of this context, except that the copy uses the supplied variables.

Parameters:

variables - the variables that should be used in the new context; may be null if there are no such variables

Returns:

the new context; never null