This package provides support for communication with Erlang and representation of Erlang datatypes.
Note: By default,
jinterface is only guaranteed
to be compatible with other Erlang/OTP components from the same release as
jinterface itself. For example,
from the OTP R10 release is not compatible with an Erlang emulator from
the OTP R9 release by default.
jinterface can be set in
compatibility mode of an earlier release (not earlier that R7), though.
The compatibility mode is set by usage of the
property. By starting the jvm with the command-line argument
jinterface will be compatible
with the R9 release of OTP. Warning! You may run into trouble if
this feature is used carelessly. Always make sure that all communicating
components are either from the same Erlang/OTP release, or from release
X and release Y where all components from release Y are in compatibility
mode of release X.
represent the various Erlang datatypes.
There are two basic mechanisms for communicating with Erlang, described briefly here. Note that the two mechanisms are not intended to be used together. Which mechanism you choose depends on your application and the level of control it needs.
You can use
OtpNode, which can
manage incoming and outgoing connections for you. With
OtpNode a thread is automatically started to
listen for incoming connections, make necessary outgoing connections,
and dispatch messages to their recipients.
OtpNode supports the concept of
mailboxes, allowing you to have
several Java components communicating independently with Erlang.
OtpNode node = new OtpNode("bingo"); OtpMbox mbox = node.createMbox(); mbox.send("foo@localhost",new OtpErlangAtom("hej"));
If you need more control (but less support from the library), you
can manage connections yourself using the
OtpConnection classes, in which case you can
control explicitly which connections are made and which messages are
sent. Received messages are not dispatched by
OtpServer are used to represent OTP nodes and
are necessary in order to set up communication between the Java
thread and a remote node. Once a connection has been established, it
is represented by an
through which all communication goes.
Setting up a connection with a remote node is straightforward. You
create objects representing the local and remote nodes, then call the
OtpSelf self = new OtpSelf("client","cookie"); OtpPeer other = new OtpPeer("server"); OtpConnection conn = self.connect(other);
If you wish to be able to accept incoming connections as well as make outgoing ones, you first must register the listen port with EPMD (described in the Erlang documentation). Once that is done, you can accept incoming connections:
OtpServer self = new OtpSelf("server","cookie"); self.publishPort(); OtpConnection conn = self.accept();
OtpErlangAtom msg = new ErlangOtpAtom("hello"); conn.send("echoserver", msg); OtpErlangObject reply = conn.receive(); System.out.println("Received " + reply);
Finally, you can get an even greater level of control (and even
less support from the library) by subclassing
AbstractConnection and implementing the
communication primitives needed by your application.
Interface Summary Interface Description OtpServerTransportServer-side connection-oriented transport interface. OtpTransportClient-side connection-oriented transport interface. OtpTransportFactoryFactory class used to create client- and server-side transport instances.
Class Summary Class Description AbstractConnectionMaintains a connection between a Java process and a remote Erlang, Java or C node. AbstractNodeRepresents an OTP node. GenericQueueThis class implements a generic FIFO queue. OtpConnectionMaintains a connection between a Java process and a remote Erlang, Java or C node. OtpCookedConnectionMaintains a connection between a Java process and a remote Erlang, Java or C node. OtpEpmdProvides methods for registering, unregistering and looking up nodes with the Erlang portmapper daemon (Epmd). OtpErlangAtomProvides a Java representation of Erlang atoms. OtpErlangBinaryProvides a Java representation of Erlang binaries. OtpErlangBitstrProvides a Java representation of Erlang bitstrs. OtpErlangBooleanProvides a Java representation of Erlang booleans, which are special cases of atoms with values 'true' and 'false'. OtpErlangByteProvides a Java representation of Erlang integral types. OtpErlangCharProvides a Java representation of Erlang integral types. OtpErlangDoubleProvides a Java representation of Erlang floats and doubles. OtpErlangExternalFun OtpErlangFloatProvides a Java representation of Erlang floats and doubles. OtpErlangFun OtpErlangIntProvides a Java representation of Erlang integral types. OtpErlangListProvides a Java representation of Erlang lists. OtpErlangList.SubList OtpErlangLongProvides a Java representation of Erlang integral types. OtpErlangMapProvides a Java representation of Erlang maps. OtpErlangObjectBase class of the Erlang data type classes. OtpErlangObject.Hash OtpErlangPidProvides a Java representation of Erlang PIDs. OtpErlangPortProvides a Java representation of Erlang ports. OtpErlangRefProvides a Java representation of Erlang refs. OtpErlangShortProvides a Java representation of Erlang integral types. OtpErlangStringProvides a Java representation of Erlang strings. OtpErlangTupleProvides a Java representation of Erlang tuples. OtpErlangUIntProvides a Java representation of Erlang integral types. OtpErlangUShortProvides a Java representation of Erlang integral types. OtpExternalProvides a collection of constants used when encoding and decoding Erlang terms. OtpGenericTransportFactoryTransport factory abstract class used to create client-side and server-side transport instances defined using generic peers and local nodes (instead of a host + port combination as expected in the base OtpTransportFactory). OtpInputStreamProvides a stream for decoding Erlang terms from external format. OtpLocalNodeThis class represents local node types. OtpMboxProvides a simple mechanism for exchanging messages with Erlang processes or other instances of this class. OtpMsgProvides a carrier for Erlang messages. OtpNodeRepresents a local OTP node. OtpNodeStatusProvides a callback mechanism for receiving status change information about other nodes in the system. OtpOutputStreamProvides a stream for encoding Erlang terms to external format, for transmission or storage. OtpPeerRepresents a remote OTP node. OtpSelfRepresents an OTP node. OtpServer Deprecated.the functionality of this class has been moved to
OtpServerSocketTransportDefault socket-based server transport OtpSocketTransportDefault socket-based client transport OtpSocketTransportFactoryDefault socket-based transport factory
Exception Summary Exception Description OtpAuthExceptionException raised when a node attempts to establish a communication channel when it is not authorized to do so, or when a node sends a message containing an invalid cookie on an established channel. OtpErlangDecodeExceptionException raised when an attempt is made to create an Erlang term by decoding a sequence of bytes that does not represent the type of term that was requested. OtpErlangExceptionBase class for the other OTP erlang exception classes. OtpErlangExitException raised when a communication channel is broken. OtpErlangRangeExceptionException raised when an attempt is made to create an Erlang term with data that is out of range for the term in question. OtpExceptionBase class for the other OTP exception classes.