Java call formats

The FTP client API for Java™ provides an interface to the z/OS® FTP client that enables a user program written in Java to send subcommands for the client to process. The user program can also use this interface to retrieve output that includes the messages from the client, replies from the FTP server, and other data that is generated as the result of the request.

Each instance of the interface is represented by an FTPClient object. A user program can create multiple instances of the FTPClient object. A single user program can use these objects to establish multiple simultaneous connections to the same FTP server or to different FTP servers. The user program can multitask to different instances of the interface by requesting that the API not wait for the completion of an FTP subcommand before it returns control.

The z/OS FTP client that is used by the FTP client API is described in File Transfer Protocol (FTP) information in z/OS Communications Server: IP User's Guide and Commands and in the File Transfer Protocol information in z/OS Communications Server: IP Configuration Reference. The z/OS FTP client, when started with the FTP client API for Java, operates essentially the same as it does when invoked in an interactive environment under the z/OS UNIX shell. See z/OS FTP client behavior when invoked from the FTP client API for a description of the differences.

FTP client API for Java package uses the Java Native Interface (JNI) to interface with the z/OS FTP client using the C Java FTP client API. See FTP client API for C functions for more information about the FTP client API for C.

The FTP client API for Java uses the Java logging API (java.util.logging.Logger) to generate debug information. See documentation about the java.util.logging package for details about using the Java logging API.

Guidelines:

The user program can have more than one FTPClient object initialized and active in a single address space.
The FTP client API creates a child process for the z/OS FTP client. If you have a signal handler, you might see the SIGCHILD signal raised when the FTP client terminates; no action is required.
The z/OS FTP client contains handlers for various asynchronous signals. The FTP client API does not contain any signal handlers and does not block or explicitly raise any signals.

Requirements:

All requests that use the same FTPClient object must be made from the same thread.
The Java JVM in which the application runs must operate in 31-bit addressing mode. No other addressing modes are supported by the interface.
The application must have an OMVS segment defined (or set by default).
The interface module EZAFTPKI must be accessible to the application in the link list or in a STEPLIB or JOBLIB DD statement.
To use this package, you must include the EZAFTP.jar file in your classpath. In addition, the libEZAFTP.so file must be located in $LIBPATH so that the JNI methods can be found. The EZAFTP.jar file is installed into the directory /usr/include/java_classes and the libEZAFTP.so file is installed into the directory /usr/lib.

For more information about the FTP client API for Java, see the JavaDoc that is included in the EZAFTPDoc.jar file, which is installed into the directory /usr/include/java_classes. Download the jar file to a workstation, unpack it, and read it in a web browser.