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com.j_spaces.core
Interface IJSpace

All Superinterfaces:
JavaSpace
public interface IJSpace
extends JavaSpace

This interface represents the application view of a GigaSpace instance. It is implemented by all the Space Proxies (Embedded, Remote and Cluster).

When client receives a proxy to the space from the Lookup Service (see SpaceFinder, this proxy implements this interface, and therefore may be casted to this interface if specific GigaSpaces methods (such as clean()) are required.

Since this interface extends the JavaSpace interface, standard JavaSpaces methods may be invoked without downcasting.

The POJO UID generation and usage scenarios:
Scenario A: Inserting POJO into the Space using methods: write(), writeMultiple() Space UID for POJO can be created in three different ways:
1. The POJO object that has no key property declared. In that case, the ExternalEntry is created with empty UID. The space gets the ExternalEntry which was created and inserts it into the space. The space then generates UID for that ExternalEntry instance and writes it into the space.
2. The POJO has property which declared as a key - The converter takes the value of that property and calls the method getUID( Object name) in ClientUIDHandler class. That method returns a UID which is generated using the property value. The UID is set to the ExternalEntry object.

3. The POJO has property which declared as a key and marked as auto generate - The property must be from type java.lang.String. The ExternalEntry is created with an empty UID. The space gets the ExternalEntry which was created and inserts it into the space. The space then generates UID for that ExternalEntry instance and writes it into the space. The generated UID then been set into the POJO instance using �set� property method.


Scenario B: Fetching a POJO from the space using methods read(), readMultiple(), readIfExists(), take(), takeMultiple(), takeIfExists() etc:

1. When the POJO has no key property declared, it then will be returned without any UID. It means that only read() and write() operations can be executed on the POJO and NOT an update().

2. When the POJO has a key property declared, it then will be returned with the source value of the property but without the generated UID. The POJO can not approach the UID which was generated by the space. 3. The POJO has a property which declared as a key and auto generate - The space returns the POJO with the generated UID into the property.

Since:
1.0
See Also:
IJSpaceContainer, SpaceFinder

Field Summary
 
Fields inherited from interface net.jini.space.JavaSpace
NO_WAIT
 
Method Summary
 void clean()
          Cleans this space.
 void clear(Entry template, Transaction txn)
          Removes the entries that match the specified template and the specified transaction from this space.
 void clear(Object template, Transaction txn)
          Removes the objects that match the specified template and the specified transaction from this space.
 int count(Entry tmpl, Transaction txn)
          Count any matching entry from the space, visible under the specified transaction.
 int count(Entry tmpl, Transaction txn, int modifiers)
          Count (according to the modifiers) any matching entry from the space, visible under the specified transaction.
 int count(Object tmpl, Transaction txn)
          Count any matching object from the space, visible under the specified transaction.
 int count(Object tmpl, Transaction txn, int modifiers)
          Count (according to the modifiers) any matching object from the space, visible under the specified transaction.
 void dropClass(String className)
          Drops all Class's entries and all its templates from the space.
 Object getAdmin()
          Returns the admin object to the remote part of this space.
 IJSpaceContainer getContainer()
          Returns the container proxy this space resides in.
 SpaceURL getFinderURL()
          Returns the SpaceURL object which was used as the argument for SpaceFinder#find(SpaceURL) while looking for the space.
 String getName()
          Returns the name of this space.
 int getReadModifiers()
          Gets the proxy ReadModifiers.
 int getReadTakeModifiers()
          Deprecated. use getReadModifiers() instead
 Uuid getReferentUuid()
          Returns the unique uid of this space instance.
 IStubHandler getStubHandler()
          Returns the StubHandler of this space.
 int getUpdateModifiers()
          Gets the proxyUpdateModifiers.
 SpaceURL getURL()
          Returns the SpaceURL instance which was used to initialize the space.
 boolean isEmbedded()
          Checks whether proxy is connected to embedded or remote space.
 boolean isFifo()
          Returns true if this proxy FIFO enabled, otherwise false.
 boolean isNOWriteLeaseMode()
          Checks the write mode.
 boolean isOptimisticLockingEnabled()
          Returns status of Optimistic Lock protocol.
 boolean isSecured()
          Returns an indication : is this space secured.
 EventRegistration notify(Entry template, Transaction txn, RemoteEventListener listener, long lease, MarshalledObject handback, int notifyType)
          An extension to the standard JavaSpace.notify() method.
 EventRegistration notify(Object template, Transaction txn, long lease, com.gigaspaces.events.NotifyInfo info)
           
 EventRegistration notify(Object template, Transaction txn, RemoteEventListener listener, long lease, MarshalledObject handback)
          When objects that match this template are written, notification is sent to the given listener with a RemoteEvent that includes the handback object.
 EventRegistration notify(Object template, Transaction txn, RemoteEventListener listener, long lease, MarshalledObject handback, int modifiers)
          An extension to the standard JavaSpace.notify() method.
 void ping()
          Checks whether the space is alive and accessible.
 Entry read(Entry tmpl, Transaction txn, long timeout, int modifiers)
          Read (according to the modifiers) any matching entry from the space, blocking until one exists.
 Object read(Object tmpl, Transaction txn, long timeout)
          Read any matching object from the space, blocking until one exists.
 Object read(Object tmpl, Transaction txn, long timeout, int modifiers)
          Read (according to the modifiers) any matching object from the space, blocking until one exists.
 Entry readIfExists(Entry tmpl, Transaction txn, long timeout, int modifiers)
          Read (according to the modifiers) any matching entry from the space, returning null if there currently is none.
 Object readIfExists(Object tmpl, Transaction txn, long timeout)
          Read any matching object from the space, returning null if there currently is none.
 Object readIfExists(Object tmpl, Transaction txn, long timeout, int modifiers)
          Read (according to the modifiers) any matching object from the space, returning null if there currently is none.
 Entry[] readMultiple(Entry tmpl, Transaction txn, int limit)
          Read any matching entries from the space.
 Entry[] readMultiple(Entry tmpl, Transaction txn, int limit, int modifiers)
          Read (according to the modifiers) any matching entries from the space.
 Object[] readMultiple(Object tmpl, Transaction txn, int limit)
          Read any matching objects from the space.
 Object[] readMultiple(Object tmpl, Transaction txn, int limit, int modifiers)
          Read (according to the modifiers) any matching objects from the space.
 Object[] replace(Entry template, Entry newEntry, Transaction txn, long lease)
          Deprecated. use instead: update(Entry, Transaction, long, long, int)
 void setDefaultTransaction(Transaction txn)
          Sets default transaction to use in case that null parameter is used as transaction parameter with JavaSpace methods.
 void setFifo(boolean enabled)
          Sets FIFO mode for proxy.
 void setNOWriteLeaseMode(boolean noWriteLeaseMode)
          If set to true, Lease object will not return from write/writeMultiple operations.
 void setOptimisticLocking(boolean enabled)
          Enable/Disable Optimistic Lock protocol.
 int setReadModifiers(int readModifiers)
          Sets the read mode modifiers for proxy level.
 int setReadTakeModifiers(int newModifiers)
          Deprecated. use setReadModifiers(int) instead
 void setSecurityContext(SecurityContext sc)
          This function is called by the client (usually at the beginning of the session) in order to set a security context for the following operations.
 int setUpdateModifiers(int newModifiers)
          Sets the update mode modifiers for proxy level.
 Object snapshot(Object object)
          The process of serializing an entry for transmission to a JavaSpaces service will be identical if the same entry is used twice.
 Object take(Object tmpl, Transaction transaction, long timeout)
          Take any matching entry from the space, blocking until one exists.
 Object takeIfExists(Object tmpl, Transaction transaction, long timeout)
          Take any matching object from the space, returning null if there currently is none.
 Entry[] takeMultiple(Entry template, Transaction txn, int limit)
          Takes all the entries matching the specified template from this space.
 Object[] takeMultiple(Object template, Transaction txn, int limit)
          Takes all the entries matching the specified template from this space.
 Object[] update(Entry template, Entry newEntry, Transaction txn, long lease)
          Deprecated. use instead: update(Entry, Transaction, long, long, int)
 Entry update(Entry template, Entry updatedEntry, Transaction transaction, long lease, long timeout)
          Deprecated. use instead: update(Entry, Transaction, long, long, int)
 Entry update(Entry updatedEntry, Transaction transaction, long lease, long timeout)
          Equivalent to calling update(Entry, Transaction, long, long, int) with modifiers (if any) set by setUpdateModifiers(int).
 Entry update(Entry updatedEntry, Transaction transaction, long lease, long timeout, boolean writeIfAbsent)
          Deprecated. use instead update(Entry, Transaction, long, long, int) with UpdateModifiers.UPDATE_OR_WRITE modifier which is equivalent to setting writeIfAbsent=true.
 Entry update(Entry updatedEntry, Transaction transaction, long lease, long timeout, int updateModifiers)
          Equivalent to calling update(Object, Transaction, long, long, int) by use of a cast from Entry to Object. see it also as a reference to further semantics of this method.
 Object update(Object updatedEntry, Transaction transaction, long lease, long timeout)
          Equivalent to calling update(Object, Transaction, long, long, int) with modifiers (if any) set by setUpdateModifiers(int).
 Object update(Object updatedEntry, Transaction transaction, long lease, long timeout, int updateModifiers)
          An update operation against a space entity which it's UID is known, blocking if locked under another transaction.
 Object[] updateMultiple(Entry[] entries, Transaction transaction, long[] leases)
          Equivalent to calling updateMultiple(Entry[], Transaction, long[], int) with modifiers (if any) set by setUpdateModifiers(int).
 Object[] updateMultiple(Entry[] entries, Transaction transaction, long[] leases, int updateModifiers)
          Equivalent to calling updateMultiple(Object[], Transaction, long[], int) by use of an array of Object[] constructed as new Entry[]. see it also as a reference to further semantics of this method.
 Object[] updateMultiple(Object[] entries, Transaction transaction, long[] leases)
          Equivalent to calling updateMultiple(Object[], Transaction, long[], int) with modifiers (if any) set by setUpdateModifiers(int).
 Object[] updateMultiple(Object[] objects, Transaction transaction, long[] leases, int updateModifiers)
          Same as a single update but for a group of entities sharing the same transaction (if any), applied with the same operation modifier (or default Modifiers.NONE).
 LeaseContext write(Object object, Transaction transaction, long lease)
          Equivalent to calling write(Object, Transaction, long, long, int) with the UpdateModifiers.UPDATE_OR_WRITE.
 LeaseContext write(Object object, Transaction transaction, long lease, long timeout, int modifiers)
          Writes a new object to the space, returning its Lease.
 Lease[] writeMultiple(Entry[] entries, Transaction txn, long lease)
          Writes the specified entries to this space.
 LeaseContext[] writeMultiple(Object[] objects, Transaction txn, long lease)
          Writes the specified objects to this space.
 
Methods inherited from interface net.jini.space.JavaSpace
notify, read, readIfExists, snapshot, take, takeIfExists, write
 

Method Detail

getName

String getName()
Returns the name of this space. 

 IJSpace aSpace = (IJSpace)SpaceFinder.find("jini://lookup-host/container-name/");
 String name = aSpace.getName();

Returns:
the name of this space.

count

int count(Entry tmpl,
          Transaction txn)
          throws UnusableEntryException,
                 TransactionException,
                 RemoteException
Count any matching entry from the space, visible under the specified transaction.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
Returns:
The number of matching entries.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs

count

int count(Entry tmpl,
          Transaction txn,
          int modifiers)
          throws UnusableEntryException,
                 TransactionException,
                 RemoteException
Count (according to the modifiers) any matching entry from the space, visible under the specified transaction.

Overloads count(Entry, Transaction) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
modifiers - one or a union of ReadModifiers.
Returns:
The number of matching entries.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs

count

int count(Object tmpl,
          Transaction txn)
          throws UnusableEntryException,
                 TransactionException,
                 RemoteException
Count any matching object from the space, visible under the specified transaction.

Overloads count(Entry, Transaction) by replacing the Entry template with Object, to support Plain Old Java Object templates. Equivalent when called with an Entry cast to Object.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
Returns:
The number of matching objects.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs

count

int count(Object tmpl,
          Transaction txn,
          int modifiers)
          throws UnusableEntryException,
                 TransactionException,
                 RemoteException
Count (according to the modifiers) any matching object from the space, visible under the specified transaction.

Overloads count(Object, Transaction) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
modifiers - one or a union of ReadModifiers.
Returns:
The number of matching objects.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs

read

Entry read(Entry tmpl,
           Transaction txn,
           long timeout,
           int modifiers)
           throws UnusableEntryException,
                  TransactionException,
                  InterruptedException,
                  RemoteException
Read (according to the modifiers) any matching entry from the space, blocking until one exists. Return null if the timeout expires.

Overloads JavaSpace.read(Entry, Transaction, long) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching entry. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the entry read from the space.
Throws:
UnusableEntryException - if any serialized field of the entry being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
Since:
6.0
See Also:
JavaSpace.read(Entry, Transaction, long)

read

Object read(Object tmpl,
            Transaction txn,
            long timeout)
            throws UnusableEntryException,
                   TransactionException,
                   InterruptedException,
                   RemoteException
Read any matching object from the space, blocking until one exists. Return null if the timeout expires.

Overloads JavaSpace.read(Entry, Transaction, long) by replacing the Entry template with Object, to support Plain Old Java Object templates. Equivalent when called with an Entry cast to Object.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching object. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
Returns:
a copy of the object read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
See Also:
JavaSpace.read(Entry, Transaction, long)

read

Object read(Object tmpl,
            Transaction txn,
            long timeout,
            int modifiers)
            throws UnusableEntryException,
                   TransactionException,
                   InterruptedException,
                   RemoteException
Read (according to the modifiers) any matching object from the space, blocking until one exists. Return null if the timeout expires.

Overloads read(Object, Transaction, long) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching object. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the object read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
Since:
6.0
See Also:
read(Object, Transaction, long)

readIfExists

Entry readIfExists(Entry tmpl,
                   Transaction txn,
                   long timeout,
                   int modifiers)
                   throws UnusableEntryException,
                          TransactionException,
                          InterruptedException,
                          RemoteException
Read (according to the modifiers) any matching entry from the space, returning null if there currently is none. Matching and timeouts are done as in read, except that blocking in this call is done only if necessary to wait for transactional state to settle.

Overloads JavaSpace.readIfExists(Entry, Transaction, long) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching entry. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the entry read from the space
Throws:
UnusableEntryException - if any serialized field of the entry being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
Since:
6.0
See Also:
JavaSpace.readIfExists(Entry, Transaction, long), read(Entry, Transaction, long, int)

readIfExists

Object readIfExists(Object tmpl,
                    Transaction txn,
                    long timeout)
                    throws UnusableEntryException,
                           TransactionException,
                           InterruptedException,
                           RemoteException
Read any matching object from the space, returning null if there currently is none. Matching and timeouts are done as in read, except that blocking in this call is done only if necessary to wait for transactional state to settle.

Overloads JavaSpace.readIfExists(Entry, Transaction, long) by replacing the Entry template with Object, to support Plain Old Java Object templates. Equivalent when called with an Entry cast to Object.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching object. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
Returns:
a copy of the object read from the space
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
See Also:
JavaSpace.readIfExists(Entry, Transaction, long), read(Entry, Transaction, long, int)

readIfExists

Object readIfExists(Object tmpl,
                    Transaction txn,
                    long timeout,
                    int modifiers)
                    throws UnusableEntryException,
                           TransactionException,
                           InterruptedException,
                           RemoteException
Read (according to the modifiers) any matching object from the space, returning null if there currently is none. Matching and timeouts are done as in read, except that blocking in this call is done only if necessary to wait for transactional state to settle.

Overloads readIfExists(Object, Transaction, long) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
timeout - How long the client is willing to wait for a transactionally proper matching object. A timeout of JavaSpace.NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the object read from the space
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
InterruptedException - if the thread in which the read occurs is interrupted
RemoteException - if a communication error occurs
Since:
6.0
See Also:
readIfExists(Object, Transaction, long), read(Object, Transaction, long, int)

readMultiple

Entry[] readMultiple(Entry tmpl,
                     Transaction txn,
                     int limit)
                     throws TransactionException,
                            UnusableEntryException,
                            RemoteException
Read any matching entries from the space. Matching is done as in read without timeout (JavaSpace.NO_WAIT). Returns an array with matches bound by limit. Returns an empty array if no match was found.

Note: Each matching entry has to be explicitly cast. 


 Entry[] results =  ijspace.readMultiple( new MyEntry(), (Transaction)null, Integer.MAX_VALUE );
 for (int i=0; i<results.length; i++)
 {
        System.out.println( (MyEntry)results[i]) );
 }

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
limit - a limit on the number of entries to be returned. Use Integer.MAX_VALUE for the uppermost limit.
Returns:
a copy of the entries read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs

readMultiple

Entry[] readMultiple(Entry tmpl,
                     Transaction txn,
                     int limit,
                     int modifiers)
                     throws TransactionException,
                            UnusableEntryException,
                            RemoteException
Read (according to the modifiers) any matching entries from the space. Matching is done as in read without timeout (JavaSpace.NO_WAIT). Returns an array with matches bound by limit. Returns an empty array if no match was found.

Overloads readMultiple(Entry, Transaction, int) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
limit - a limit on the number of entries to be returned. Use Integer.MAX_VALUE for the uppermost limit.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the entries read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs
Since:
6.0
See Also:
readMultiple(Entry, Transaction, int)

readMultiple

Object[] readMultiple(Object tmpl,
                      Transaction txn,
                      int limit)
                      throws TransactionException,
                             UnusableEntryException,
                             RemoteException
Read any matching objects from the space. Matching is done as in read without timeout (JavaSpace.NO_WAIT). Returns an array with matches bound by limit. Returns an empty array if no match was found.

Overloads readMultiple(Entry, Transaction, int) by replacing the Entry template with Object, to support Plain Old Java Object templates. Equivalent when called with an Entry[] cast to Object[].

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
limit - a limit on the number of objects to be returned. Use Integer.MAX_VALUE for the uppermost limit.
Returns:
a copy of the objects read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs
See Also:
readMultiple(Entry, Transaction, int)

readMultiple

Object[] readMultiple(Object tmpl,
                      Transaction txn,
                      int limit,
                      int modifiers)
                      throws TransactionException,
                             UnusableEntryException,
                             RemoteException
Read (according to the modifiers) any matching objects from the space. Matching is done as in read without timeout (JavaSpace.NO_WAIT). Returns an array with matches bound by limit. Returns an empty array if no match was found.

Overloads readMultiple(Object, Transaction, int) by adding a modifiers parameter. Equivalent when called with the default modifier - ReadModifiers#REPEATABLE_READ. Modifiers are used to define the behavior of a read operation.

Parameters:
tmpl - The template used for matching. Matching is done against tmpl with null fields being wildcards ("match anything") other fields being values ("match exactly on the serialized form").
txn - The transaction (if any) under which to work.
limit - a limit on the number of objects to be returned. Use Integer.MAX_VALUE for the uppermost limit.
modifiers - one or a union of ReadModifiers.
Returns:
a copy of the objects read from the space.
Throws:
UnusableEntryException - if any serialized field of the object being read cannot be deserialized for any reason
TransactionException - if a transaction error occurs
RemoteException - if a communication error occurs
Since:
6.0
See Also:
readMultiple(Object, Transaction, int)

clean

void clean()
           throws RemoteException
Cleans this space. The side-effects of cleaning the space are: 

 IJSpace aSpace = (IJSpace)SpaceFinder.find("jini://lookup-host/container-name/space-name");
 aSpace.clean();

Throws:
RemoteException - if a communication error occurs

getAdmin

Object getAdmin()
                throws RemoteException
Returns the admin object to the remote part of this space. 

 // get a list of classes and the number of entries of each class
 IRemoteJSpaceAdmin spaceAdmin = (IRemoteJSpaceAdmin)space.getAdmin();
 Object classList[] = spaceAdmin.getRuntimeInfo().m_ClassNames.toArray();
 List numOFEntries = spaceAdmin.getRuntimeInfo().m_NumOFEntries;

Returns:
the admin object to the remote part of this space.
Throws:
RemoteException - if a communication error occurs

ping

void ping()
          throws RemoteException
Checks whether the space is alive and accessible. 

 IJSpace aSpace = (IJSpace)SpaceFinder.find("jini://lookup-host/container-name/space-name");
 try{
    aSpace.ping();
    System.out.println("Space alive");
 }
 catch (java.rmi.RemoteException re) {
    System.out.println("Space unreachable");
 }

Throws:
RemoteException - when space was unreachable

replace

Object[] replace(Entry template,
                 Entry newEntry,
                 Transaction txn,
                 long lease)
                 throws TransactionException,
                        UnusableEntryException,
                        RemoteException
Deprecated. use instead: update(Entry, Transaction, long, long, int)

Replaces the first entry matching the specified template, if found and there is no transaction conflict. 

 IJSpace aSpace = (IJSpace)SpaceFinder.find("jini://lookup-host/container-name/space-name");
 Message tmpl = new Message("Hello World");
 Message msg = new Message("Goodbye World");
 Object[] result = aSpace.replace(tmpl, msg, null, Lease.FOREVER);
 Message old = (Message)result[0];
 long msgLease = ((Lease)result[1]).getExpiration();
 
 The replace method is not atomic (unless used with transaction)
 which means that the former call equals to:
 
 Message old = (Message)aSpace.take(tmpl, null, JavaSpace.NO_WAIT);
 Lease lease = aSpace.write(msg, null, Lease.FOREVER);

Parameters:
template - the template to use for matching.
newEntry - the value of the new entry.
txn - the transaction under which to perform the operation.
lease - the lease time of the new entry
Returns:
an array of 2 elements: the first element is the old object and the second element is the new lease. If not matching entry was found, null is returned.
Throws:
TransactionException - if a transaction error occurs
UnusableEntryException - if any serialized field of the entry being read cannot be deserialized for any reason
RemoteException - if a communication error occurs
IllegalArgumentException - if the lease time requested is not Lease.ANY and is negative
See Also:
update(Entry, Entry, Transaction, long)

update

Object update(Object updatedEntry,
              Transaction transaction,
              long lease,
              long timeout)
              throws TransactionException,
                     UnusableEntryException,
                     RemoteException,
                     InterruptedException
Equivalent to calling update(Object, Transaction, long, long, int) with modifiers (if any) set by setUpdateModifiers(int).

Parameters:
updatedEntry - the new value of the entry, must contain the UID.
transac