edu.cmu.aura.service.db
Class Database

java.lang.Object
  |
  +--edu.cmu.aura.service.db.Database

All Implemented Interfaces:

DataSink, PrimitiveService, java.rmi.Remote

public class Database

extends java.lang.Object

implements PrimitiveService, DataSink

Database provides a simple Database oriented implementation of PrimitiveService. It is currently designed for functionality over performance and scalability.

Field Summary

Fields inherited from interface edu.cmu.aura.service.PrimitiveService

ALL_ATTRIBS, ANY_CHANGE, DEFAULT_EXEC_INTERVAL, DEFAULT_SERVICE, DEFAULT_SERVICE_NAME, NO_REQS, NO_TIME_LIMIT, RELATION_ATTRIB, SELECT_ALL

Constructor Summary

Database(java.lang.String name)
Create a new Database.

Method Summary

void	addTable(edu.cmu.aura.service.db.Table table) Add a table to this Database.
void	delete(java.lang.String serviceName, java.util.ArrayList keyVal) Delete an entry from the service database.
void	display() Display the entire Database.
java.lang.String	getName() Get the name of this Database.
int	getPort() Get the port on which this database is accepting incoming requests.
edu.cmu.aura.service.db.Table	getTableByName(java.lang.String name) Get a specified table.
void	insert(java.lang.String serviceName, java.util.ArrayList attribs) Insert an entry into the service database.
int	postCondTrigger(java.util.ArrayList sAttribs, java.util.ArrayList serviceNames, ExpressionNode expression, java.util.ArrayList attribReqs, long timeLimit, long execInterval, ExpressionNode triggerExpression, edu.cmu.aura.service.rpc.RemoteReference queryClient) Post a trigger that is to execute when a particular condition is met.
int	postModTrigger(java.util.ArrayList sAttribs, java.util.ArrayList serviceNames, ExpressionNode expression, java.util.ArrayList attribReqs, long timeLimit, long execInterval, java.util.ArrayList triggerAttribs, java.util.ArrayList triggerDeltas, edu.cmu.aura.service.rpc.RemoteReference queryClient) Post a trigger that is to execute when any one of a given set of attributes changes by a specified amount.
int	postQuery(java.util.ArrayList selectedAttribs, java.util.ArrayList serviceNames, ExpressionNode expression, java.util.ArrayList attribReqs, long timeLimit, long execInterval, edu.cmu.aura.service.rpc.RemoteReference queryClient) Query a service recurrently.
QueryResult	query(java.util.ArrayList selectedAttributes, java.util.ArrayList serviceNames, ExpressionNode expression, java.util.ArrayList attribReqs, long timeLimit) Execute a query against this Database.
void	removeQuery(java.lang.String serviceName, int queryID) Remove a recurrent query.
void	removeTrigger(java.lang.String serviceName, int queryID) Remove a trigger.
void	start() Should be called before the database is accessed.
void	update(java.lang.String serviceName, java.util.ArrayList keyVal, java.util.ArrayList attribs) Update an entry's attributes in the service database.

Methods inherited from class java.lang.Object

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

Constructor Detail

Database

public Database(java.lang.String name)

Create a new Database.

Parameters:

name - the name of this Database.

Method Detail

start

public void start()

Should be called before the database is accessed. Currently this method starts all database updaters.

getName

public java.lang.String getName()

Get the name of this Database.

Returns:

the name of this Database.

getPort

public int getPort()

Get the port on which this database is accepting incoming requests.

Returns:

the port on which this database is accepting incoming requests.

addTable

public void addTable(edu.cmu.aura.service.db.Table table)

Add a table to this Database.

getTableByName

public edu.cmu.aura.service.db.Table getTableByName(java.lang.String name)

Get a specified table.

Parameters:

name - the name of the table to get.

Returns:

the specified table.

display

public void display()

Display the entire Database. This is primarily for debugging.

query

public QueryResult query(java.util.ArrayList selectedAttributes,
                         java.util.ArrayList serviceNames,
                         ExpressionNode expression,
                         java.util.ArrayList attribReqs,
                         long timeLimit)
                  throws ServiceException

Execute a query against this Database.

Specified by:

query in interface PrimitiveService

Parameters:

serviceNames - names of services to retrieve attributes from.

expression - expression selecting which entities or relations in the service should be returned.

attribReqs - requirements on dynamic attributes.

timeLimit - this is used by clients to inform the service on when they need the results by. This may also be viewed as a suggestion on how hard to work to retrieve the results.

selectedAttributes - attribsutes to select. ALL_ATTRIBS indicates that all attributes are to be selected.

Returns:

the QueryResult of the query.

ServiceException

postQuery

public int postQuery(java.util.ArrayList selectedAttribs,
                     java.util.ArrayList serviceNames,
                     ExpressionNode expression,
                     java.util.ArrayList attribReqs,
                     long timeLimit,
                     long execInterval,
                     edu.cmu.aura.service.rpc.RemoteReference queryClient)
              throws java.rmi.RemoteException,
                     ServiceException

Query a service recurrently.

Specified by:

postQuery in interface PrimitiveService

Parameters:

selectedAttribs - the attribs to select.

serviceNames - names of services to retrieve attributes from.

expression - expression selecting which entities or relations in the service should be returned.

attribReqs - requirements on dynamic attributes.

timeLimit - this is used by clients to inform the service on when they need the results by. This may also be viewed as a suggestion on how hard to work to retrieve the results.

execInterval - interval at which to execute the query.

queryClient - the client that should be informed when this query executes.

Returns:

the QueryResult of the query.

java.rmi.RemoteException

ServiceException

postCondTrigger

public int postCondTrigger(java.util.ArrayList sAttribs,
                           java.util.ArrayList serviceNames,
                           ExpressionNode expression,
                           java.util.ArrayList attribReqs,
                           long timeLimit,
                           long execInterval,
                           ExpressionNode triggerExpression,
                           edu.cmu.aura.service.rpc.RemoteReference queryClient)
                    throws java.rmi.RemoteException,
                           ServiceException

Description copied from interface: PrimitiveService

Post a trigger that is to execute when a particular condition is met. Note that a trigger may be regarded as a posted query that executes at a particular interval. A client may request that a service check constantly by specifying an execInterval of DEFAULT_EXEC_INTERVAL, but a service is free to decide what interval to check at if it has no easy mechanism for checking constantly.

Specified by:

postCondTrigger in interface PrimitiveService

Parameters:

sAttribs - attribsutes to select. ALL_ATTRIBS indicates that all attributes are to be selected.

serviceNames - names of services to retrieve attributes from. DEFAULT_SERVICE may be used if there is only one service listening on a given port.

expression - expression selecting which entities or relations in the service should be returned. SELECT_ALL indicates all entities are to be selected.

attribReqs - requirements on dynamic attributes. NO_REQS indicates there are no requirements in effect.

timeLimit - this is used by clients to inform the service on when they need the results by. This may also be viewed as a suggestion on how hard to work to retrieve the results. NO_TIME_LIMIT indicates that the client has no hard limit on how long the processing should take; though a client will likely still desire reasonably fast execution.

execInterval - interval at which to check the trigger.

triggerExpression - condition indicating when to fire the trigger.

queryClient - the client that should be informed when this trigger executes.

Returns:

the id of the posted trigger.

java.rmi.RemoteException

ServiceException

postModTrigger

public int postModTrigger(java.util.ArrayList sAttribs,
                          java.util.ArrayList serviceNames,
                          ExpressionNode expression,
                          java.util.ArrayList attribReqs,
                          long timeLimit,
                          long execInterval,
                          java.util.ArrayList triggerAttribs,
                          java.util.ArrayList triggerDeltas,
                          edu.cmu.aura.service.rpc.RemoteReference queryClient)
                   throws java.rmi.RemoteException,
                          ServiceException

Description copied from interface: PrimitiveService

Post a trigger that is to execute when any one of a given set of attributes changes by a specified amount. Note that a trigger may be regarded as a posted query that executes at a particular interval. A client may request that a service check constantly by specifying an execInterval of DEFAULT_EXEC_INTERVAL, but a service is free to decide what interval to check at if it has no easy mechanism for checking constantly.

Specified by:

postModTrigger in interface PrimitiveService

Parameters:

sAttribs - attribsutes to select. ALL_ATTRIBS indicates that all attributes are to be selected.

serviceNames - names of services to retrieve attributes from. DEFAULT_SERVICE may be used if there is only one service listening on a given port.

expression - expression selecting which entities or relations in the service should be returned. SELECT_ALL indicates all entities are to be selected.

attribReqs - requirements on dynamic attributes. NO_REQS indicates there are no requirements in effect.

timeLimit - this is used by clients to inform the service on when they need the results by. This may also be viewed as a suggestion on how hard to work to retrieve the results. NO_TIME_LIMIT indicates that the client has no hard limit on how long the processing should take; though a client will likely still desire reasonably fast execution.

execInterval - interval at which to check the trigger.

triggerAttribs - attributes to watch for changes.

triggerDeltas - amount of change that will cause the trigger to fire for the corresponding attribute.

queryClient - the client that should be informed when this trigger executes.

Returns:

the id of the posted trigger.

java.rmi.RemoteException

ServiceException

removeTrigger

public void removeTrigger(java.lang.String serviceName,
                          int queryID)
                   throws java.rmi.RemoteException,
                          ServiceException

Description copied from interface: PrimitiveService

Remove a trigger.

Specified by:

removeTrigger in interface PrimitiveService

Parameters:

serviceName - name of the service to remove the query from.

queryID - the ID of the query to remove.

java.rmi.RemoteException

ServiceException

removeQuery

public void removeQuery(java.lang.String serviceName,
                        int queryID)
                 throws ServiceException,
                        java.rmi.RemoteException

Remove a recurrent query.

Specified by:

removeQuery in interface PrimitiveService

Parameters:

serviceName - name of the service to remove the query from.

queryID - the ID of the query to remove.

ServiceException

java.rmi.RemoteException

update

public void update(java.lang.String serviceName,
                   java.util.ArrayList keyVal,
                   java.util.ArrayList attribs)
            throws ServiceException,
                   java.rmi.RemoteException

Description copied from interface: DataSink

Update an entry's attributes in the service database. A new entry will be created if one matching the keyVal is not found.

Specified by:

update in interface DataSink

Parameters:

serviceName - name of the service to update

keyVal - key value of the entry to update

attribs - updated attributes

ServiceException

java.rmi.RemoteException

insert

public void insert(java.lang.String serviceName,
                   java.util.ArrayList attribs)
            throws ServiceException

Description copied from interface: DataSink

Insert an entry into the service database. An error will occur if the entry already exists. When no entry exists, this function has the same effect as calling update, but requires one less argument.

Specified by:

insert in interface DataSink

Parameters:

serviceName - name of the service to insert into

attribs - updated attributes

ServiceException

delete

public void delete(java.lang.String serviceName,
                   java.util.ArrayList keyVal)
            throws ServiceException

Description copied from interface: DataSink

Delete an entry from the service database.

Specified by:

delete in interface DataSink

Parameters:

serviceName - name of the service to delete from

keyVal - key value of entry to delete

ServiceException