The integrated file system classes allow a Java™ program to access files in the integrated file system of an iSeries™ server as a stream of bytes or a stream of characters. The integrated file system classes were created because the java.io package does not provide file redirection and other iSeries functionality.
The function that is provided by the IFSFile classes is a superset of the function provided by the file IO classes in the java.io package. All methods in java.io FileInputStream, FileOutputStream, and RandomAccessFile are in the integrated file system classes.
In addition, the classes contain methods to do the following:
- Specify a file sharing mode to deny access to the file while it is in use
- Specify a file creation mode to open, create, or replace the file
- Lock a section of the file and deny access to that part of the file while it is in use
- List the contents of a directory more efficiently
- Cache the contents of a directory to improve performance by limiting calls to the server
- Determine the number of bytes available on the server file system
- Allow a Java applet to access files in the server file system
- Read and write data as text instead of as binary data
- Determine the type of the file object (logical, physical, save, and so on) when the object is in the QSYS.LIB file system
Through the integrated file system classes, the Java program can directly access stream files on the iSeries. The Java program can still use the java.io package, but the client operating system must then provide a method of redirection. For example, if the Java program is running on a Windows® 95 or Windows NT® operating system, the Network Drives function of iSeries Access for Windows is required to redirect java.io calls to the iSeries. With the integrated file system classes, you do not need iSeries Access for Windows.
A required parameter of the integrated file system classes is the AS400 object that represents the iSeries system that contains the file. Using the integrated file system classes causes the AS400 object to connect to the iSeries. See managing connections for information about managing connections.
The integrated file system classes require the hierarchical name of the object in the integrated file system. Use the forward slash as the path separator character. The following example shows how to access FILE1 in directory path DIR1/DIR2:
/DIR1/DIR2/FILE1
Integrated file system classes
The following table lists the integrated file system classes:
| Integrated file system class | Description |
|---|---|
| IFSFile | Represents a file in the integrated file system |
| IFSJavaFile | Represents a file in the integrated file system (extends java.io.File) |
| IFSFileInputStream | Represents an input stream for reading data from an iSeries file |
| IFSTextFileInputStream | Represents a stream of character data read from a file (deprecated) |
 IFSFileReader |
Use this class for reading character files in the integrated
file system. |
| IFSFileOutputStream | Represents an output stream for writing data to an iSeries file |
| IFSFileWriter |
Use IFSFileWriter for writing character files in the
integrated file system. |
| IFSTextFileOutputStream | Represents a stream of character data being written to a file (deprecated) |
| IFSRandomAccessFile | Represents a file on the iSeries for reading and writing data |
| IFSFileDialog | Allows the user to move within the file system and to select a file within the file system |
| IFSSystemView |
IFSSystemView provides a gateway to the iSeries integrated file system, for use
when constructing javax.swing.JFileChooser objects. |
Examples: Using integrated file system classes
Example: Using IFS classes to copy a file from one directory to another shows how to use the integrated file system classes to copy a file from one directory to another on the iSeries.
Example: Using the IFS classes to list the contents of a directory shows how to use the integrated file system classes to list the contents of a directory on the iSeries.