Package com.ibm.as400.access

Class IFSFileReader

java.lang.Object

java.io.Reader

com.ibm.as400.access.IFSFileReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class IFSFileReader
extends Reader

Convenience class for reading character files in the integrated file system. The behavior of this class is comparable to java.io.FileReader.
IFSFileReader is meant for reading streams of characters. For reading streams of raw bytes, use IFSFileInputStream. If an InputStream is required, use IFSTextFileInputStream.

The following example illustrates the use of IFSFileReader:

import java.io.BufferedReader;
// Work with /File1 on the system eniac.
AS400 system = new AS400("eniac");
IFSFile file = new IFSFile(system, "/File1");
BufferedReader reader = new BufferedReader(new IFSFileReader(file));
// Read the first line of the file, converting characters.
String line1 = reader.readLine();
// Display the String that was read.
System.out.println(line1);
// Close the reader.
reader.close();

Field Summary

Fields

Modifier and Type	Field	Description
static int	SHARE_ALL	Share option that allows read and write access by other users.
static int	SHARE_NONE	Share option that does not allow read or write access by other users.
static int	SHARE_READERS	Share option that allows only read access by other users.
static int	SHARE_WRITERS	Share option that allows only write access by other users.

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor	Description
IFSFileReader(IFSFile file)	Constructs an IFSFileReader object.
IFSFileReader(IFSFileDescriptor fd)	Constructs an IFSFileReader object.
IFSFileReader(IFSFile file, int ccsid)	Constructs an IFSFileReader object.
IFSFileReader(IFSFile file, int ccsid, int shareOption)	Constructs an IFSFileReader object.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the stream.
int	getCCSID()	Returns the CCSID used by this IFSFileReader.
String	getEncoding()	Returns the encoding used by this IFSFileReader.
IFSKey	lockBytes(int length)	Deprecated. Replaced by lock(long)
IFSKey	lockBytes(long length)	Places a lock on the file at the current position for the specified number of bytes.
boolean	markSupported()	IFSFileReader does not support the mark() operation.
int	read()	Reads a single character.
int	read(char[] cbuf)	Reads characters into an array.
int	read(char[] cbuf, int off, int len)	Reads characters into a portion of an array.
boolean	ready()	Tells whether this stream is ready to be read.
void	reset()	Resets the stream.
long	skip(long charsToSkip)	Skip characters.
void	unlockBytes(IFSKey key)	Undoes a lock on the file.

Methods inherited from class java.io.Reader

mark, nullReader, read, transferTo

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SHARE_ALL

public static final int SHARE_ALL

Share option that allows read and write access by other users.

See Also:

Constant Field Values

SHARE_NONE

public static final int SHARE_NONE

Share option that does not allow read or write access by other users.

See Also:

Constant Field Values

SHARE_READERS

public static final int SHARE_READERS

Share option that allows only read access by other users.

See Also:

Constant Field Values

SHARE_WRITERS

public static final int SHARE_WRITERS

Share option that allows only write access by other users.

See Also:

Constant Field Values

Constructor Detail

IFSFileReader

public IFSFileReader(IFSFile file)
              throws AS400SecurityException,
                     IOException

Constructs an IFSFileReader object. Other readers and writers are allowed to access the file. The file is opened if it exists; otherwise an exception is thrown. The file's CCSID is obtained by referencing the file's "coded character set ID" tag on the system. Other readers and writers are allowed to access the file.

Parameters:

file - The file to be opened for reading.

Throws:

AS400SecurityException - If a security or authority error occurs.

IOException - If an error occurs while communicating with the system.

IFSFileReader

public IFSFileReader(IFSFile file,
                     int ccsid)
              throws AS400SecurityException,
                     IOException

Constructs an IFSFileReader object. The file is opened if it exists; otherwise an exception is thrown. Other readers and writers are allowed to access the file.

Parameters:

file - The file to be opened for reading.

ccsid - The CCSID that the file data is currently in.

Throws:

AS400SecurityException - If a security or authority error occurs.

IOException - If an error occurs while communicating with the system.

IFSFileReader

public IFSFileReader(IFSFile file,
                     int ccsid,
                     int shareOption)
              throws AS400SecurityException,
                     IOException

Constructs an IFSFileReader object. The file is opened if it exists; otherwise an exception is thrown.

Parameters:

file - The file to be opened for reading.

ccsid - The CCSID that the file data is currently in.

shareOption - Indicates how users can access the file.

• SHARE_ALL Share access with readers and writers
• SHARE_NONE Share access with none
• SHARE_READERS Share access with readers
• SHARE_WRITERS Share access with writers

Throws:

AS400SecurityException - If a security or authority error occurs.

IOException - If an error occurs while communicating with the system.

IFSFileReader

public IFSFileReader(IFSFileDescriptor fd)
              throws AS400SecurityException,
                     IOException

Constructs an IFSFileReader object. The file is opened if it exists; otherwise an exception is thrown.

Parameters:

fd - The file descriptor to be opened for reading.

Throws:

AS400SecurityException - If a security or authority error occurs.

IOException - If an error occurs while communicating with the system.

Method Detail

close

public void close()
           throws IOException

Closes the stream. Once a stream has been closed, further read(), ready(), mark(), or reset() invocations will throw an IOException. Closing a previously-closed stream, however, has no effect.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException - If an error occurs while communicating with the system.

getCCSID

public int getCCSID()

Returns the CCSID used by this IFSFileReader.

Returns:

The CCSID, or -1 if the CCSID is not known.

getEncoding

public String getEncoding()

Returns the encoding used by this IFSFileReader.

Returns:

The encoding, or null if the encoding is not known.

markSupported

public boolean markSupported()

IFSFileReader does not support the mark() operation.

Overrides:

markSupported in class Reader

Returns:

false.

read

public int read()
         throws IOException

Reads a single character.

Overrides:

read in class Reader

Returns:

The character read, or -1 if the end of the stream has been reached.

Throws:

IOException - If an error occurs while communicating with the system.

read

public int read(char[] cbuf)
         throws IOException

Reads characters into an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Overrides:

read in class Reader

Parameters:

cbuf - Destination buffer.

Returns:

The number of characters read, or -1 if the end of the stream has been reached.

Throws:

IOException - If an error occurs while communicating with the system.

read

public int read(char[] cbuf,
                int off,
                int len)
         throws IOException

Reads characters into a portion of an array. This method will block until some input is available, an I/O error occurs, or the end of the stream is reached.

Specified by:

read in class Reader

Parameters:

cbuf - Destination buffer.

off - Offset at which to start storing characters.

len - Maximum number of characters to read.

Returns:

The number of characters read, or -1 if the end of the stream has been reached.

Throws:

IOException - If an error occurs while communicating with the system.

ready

public boolean ready()
              throws IOException

Tells whether this stream is ready to be read.

Overrides:

ready in class Reader

Returns:

true if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.

Throws:

IOException - If an error occurs while communicating with the system.

reset

public void reset()
           throws IOException

Resets the stream. After this call, the stream will read from the beginning.

Overrides:

reset in class Reader

Throws:

IOException - If an error occurs while communicating with the system.

skip

public long skip(long charsToSkip)
          throws IOException

Skip characters. This method will block until some characters are available, an I/O error occurs, or the end of the stream is reached.

Overrides:

skip in class Reader

Parameters:

charsToSkip - The number of characters to skip.

Returns:

The number of characters actually skipped.

Throws:

IOException - If an error occurs while communicating with the system.

lockBytes

public IFSKey lockBytes(int length)
                 throws IOException

Deprecated.

Replaced by lock(long)

Places a lock on the file at the current position for the specified number of bytes. Note: This method is not supported for files under QSYS.

Parameters:

length - The number of bytes to lock.

Returns:

The key for undoing this lock.

Throws:

IOException - If an error occurs while communicating with the system.

See Also:

unlockBytes(com.ibm.as400.access.IFSKey)

lockBytes

public IFSKey lockBytes(long length)
                 throws IOException

Places a lock on the file at the current position for the specified number of bytes. Note: This method is not supported for files under QSYS.

Parameters:

length - The number of bytes to lock.

Returns:

The key for undoing this lock.

Throws:

IOException - If an error occurs while communicating with the system.

See Also:

unlockBytes(com.ibm.as400.access.IFSKey)

unlockBytes

public void unlockBytes(IFSKey key)
                 throws IOException

Undoes a lock on the file. Note: This method is not supported for files under QSYS.

Parameters:

key - The key for the lock.

Throws:

IOException - If an error occurs while communicating with the system.

See Also:

lockBytes(long)