Package net.jini.space

Interface JavaSpace

All Known Subinterfaces:
IDirectSpaceProxy, ISpaceProxy
All Known Implementing Classes:
AbstractDirectSpaceProxy, AbstractSpaceCacheContainer, AbstractSpaceProxy, LocalCacheContainer, LocalViewContainer, SpaceProxyImpl
public interface JavaSpace
This interface is implemented by servers that export a JavaSpaces(TM) technology service. The operations in this interface are the public methods that all such spaces support.
Author:
Sun Microsystems, Inc.
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final long
    NO_WAIT
    Wait for no time at all.

  • Method Summary

    Modifier and Type
    Method
    Description
    EventRegistration
    notify(Entry tmpl, Transaction txn, RemoteEventListener listener, long lease, MarshalledObject handback)
    When entries are written that match this template notify the given listener with a RemoteEvent that includes the handback object.
    Entry
    read(Entry tmpl, Transaction txn, long timeout)
    Read any matching entry from the space, blocking until one exists.
    Entry
    readIfExists(Entry tmpl, Transaction txn, long timeout)
    Read any matching entry from the space, returning null if there is currently is none.
    Entry
    snapshot(Entry e)
    The process of serializing an entry for transmission to a JavaSpaces service will be identical if the same entry is used twice.
    Entry
    take(Entry tmpl, Transaction txn, long timeout)
    Take a matching entry from the space, waiting until one exists.
    Entry
    takeIfExists(Entry tmpl, Transaction txn, long timeout)
    Take a matching entry from the space, returning null if there is currently is none.
    Lease
    write(Entry entry, Transaction txn, long lease)
    Write a new entry into the space.

  • Field Details

  • Method Details

    • write

      Lease write(Entry entry, Transaction txn, long lease) throws TransactionException, RemoteException
      Write a new entry into the space. Equivalent to calling IPojoSpace.write(Object, Transaction, long, long, int) with UpdateModifiers.WRITE_ONLY.
      Parameters:
      entry - the entry to write
      txn - the transaction object, if any, under which to perform the write
      lease - the requested lease time, in milliseconds
      Returns:
      a lease for the entry that was written to the space
      Throws:
      TransactionException - if a transaction error occurs
      RemoteException - if a communication error occurs

    • read

      Entry read(Entry tmpl, Transaction txn, long timeout) throws UnusableEntryException, TransactionException, InterruptedException, RemoteException
      Read any matching entry from the space, blocking until one exists. Return null if the timeout expires.
      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 NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
      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
      IllegalArgumentException - if a negative timeout value is used

    • readIfExists

      Entry readIfExists(Entry tmpl, Transaction txn, long timeout) throws UnusableEntryException, TransactionException, InterruptedException, RemoteException
      Read any matching entry from the space, returning null if there is 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.
      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 NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
      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
      IllegalArgumentException - if a negative timeout value is used
      See Also:

    • take

      Entry take(Entry tmpl, Transaction txn, long timeout) throws UnusableEntryException, TransactionException, InterruptedException, RemoteException
      Take a matching entry from the space, waiting until one exists. Matching is and timeout done as for read.
      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 NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
      Returns:
      the entry taken 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 take occurs is interrupted
      RemoteException - if a communication error occurs
      IllegalArgumentException - if a negative timeout value is used
      See Also:

    • takeIfExists

      Entry takeIfExists(Entry tmpl, Transaction txn, long timeout) throws UnusableEntryException, TransactionException, InterruptedException, RemoteException
      Take a matching entry from the space, returning null if there is currently is none. Matching is and timeout done as for read, except that blocking in this call is done only if necessary to wait for transactional state to settle.
      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 NO_WAIT means to wait no time at all; this is equivalent to a wait of zero.
      Returns:
      the entry taken 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 take occurs is interrupted
      RemoteException - if a communication error occurs
      IllegalArgumentException - if a negative timeout value is used
      See Also:

    • notify

      EventRegistration notify(Entry tmpl, Transaction txn, RemoteEventListener listener, long lease, MarshalledObject handback) throws TransactionException, RemoteException
      When entries are written that match this template notify the given listener with a RemoteEvent that includes the handback object. Matching is done as for read.
      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.
      listener - The remote event listener to notify.
      lease - the requested lease time, in milliseconds
      handback - An object to send to the listener as part of the event notification.
      Returns:
      the event registration to the the registrant
      Throws:
      TransactionException - if a transaction error occurs
      RemoteException - if a communication error occurs
      IllegalArgumentException - if the lease time requested is not Lease.ANY and is negative
      See Also:

    • snapshot

      Entry snapshot(Entry e) throws RemoteException
      The process of serializing an entry for transmission to a JavaSpaces service will be identical if the same entry is used twice. This is most likely to be an issue with templates that are used repeatedly to search for entries with read or take. The client-side implementations of read and take cannot reasonably avoid this duplicated effort, since they have no efficient way of checking whether the same template is being used without intervening modification. The snapshot method gives the JavaSpaces service implementor a way to reduce the impact of repeated use of the same entry. Invoking snapshot with an Entry will return another Entry object that contains a snapshot of the original entry. Using the returned snapshot entry is equivalent to using the unmodified original entry in all operations on the same JavaSpaces service. Modifications to the original entry will not affect the snapshot. You can snapshot a null template; snapshot may or may not return null given a null template. The entry returned from snapshot will be guaranteed equivalent to the original unmodified object only when used with the space. Using the snapshot with any other JavaSpaces service will generate an IllegalArgumentException unless the other space can use it because of knowledge about the JavaSpaces service that generated the snapshot. The snapshot will be a different object from the original, may or may not have the same hash code, and equals may or may not return true when invoked with the original object, even if the original object is unmodified. A snapshot is guaranteed to work only within the virtual machine in which it was generated. If a snapshot is passed to another virtual machine (for example, in a parameter of an RMI call), using it--even with the same JavaSpaces service--may generate an IllegalArgumentException.
      Parameters:
      e - the entry to take a snapshot of.
      Returns:
      a snapshot of the entry.
      Throws:
      RemoteException - if a communication error occurs