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Interface org.jos.fs.Medium

public interface Medium

Attention: A Medium is not a drive. If a disk is ejected out of a disk drive and another one is inserted, this second disk has to be modeled by a new Medium instance!

All implementations of this interface must be thread-safe!

Changes 3-2-98: changed references to EjectionVetoException into VetoException

Version:

JOS-FileSystem 4 Preview (25-Mar-98)

Author:

Stefan Reich

READONLY

Flag: Medium is read-only

REMOUNTABLE

Flag: Medium is remountable without user interaction (jukebox)

"Remount" can also mean "reestablish a connection", e.g.

REMOVABLE

Flag: Medium is removable

REMOVABLE_WITHOUT_NOTIFICATION

Flag: Medium can be removed without notification of listeners (e.g., because the drive hardware doesn't report removals)

addMediumListener(MediumListener)

add a listener

eject()

ejects medium if ejectable.

eject() should perform the following steps:

• fire a mediumWillEject() event to all listeners
• if a listener throws a EjectionVetoException, rethrow it and cancel operation
• fire a mediumEjects() event to all listeners
• do the physical ejection
• isRemoved has to return true from now on

flush()

flushes all buffers if neccessary

getFlags()

returns the flags (a constant value - not allowed to change during the instance's lifetime)

getSize()

returns total size (in Bytes)

isRemoved()

is medium ejected?

readBytes(long, byte[], int, int)

reads bytes from medium

remount()

remounts the device.

If it doesn't throw an IOException, it was successful and the medium is accessible again.

Attention: The medium contents may have changed.

removeMediumListener(MediumListener)

remove a listener

writeBytes(long, byte[], int, int)

writes bytes to medium

public static final int READONLY

Flag: Medium is read-only

public static final int REMOVABLE

Flag: Medium is removable

public static final int REMOVABLE_WITHOUT_NOTIFICATION

Flag: Medium can be removed without notification of listeners (e.g., because the drive hardware doesn't report removals)

public static final int REMOUNTABLE

Flag: Medium is remountable without user interaction (jukebox)

"Remount" can also mean "reestablish a connection", e.g. a FTP connection that broke down because of a timeout.

public abstract int getFlags()

returns the flags (a constant value - not allowed to change during the instance's lifetime)

public abstract long getSize()

returns total size (in Bytes)

public abstract void readBytes(long ofs,
                               byte[] buf,
                               int bOfs,
                               int count) throws IOException, MediumRemovedException, IllegalArgumentException

reads bytes from medium

public abstract void writeBytes(long ofs,
                                byte[] buf,
                                int bOfs,
                                int count) throws IOException, MediumRemovedException, IllegalArgumentException, UnsupportedFeatureException

writes bytes to medium

public abstract void flush() throws IOException

flushes all buffers if neccessary

public abstract void eject() throws MediumRemovedException, VetoException, IOException, UnsupportedFeatureException

ejects medium if ejectable.

eject() should perform the following steps:

• fire a mediumWillEject() event to all listeners
• if a listener throws a EjectionVetoException, rethrow it and cancel operation
• fire a mediumEjects() event to all listeners
• do the physical ejection
• isRemoved has to return true from now on

public abstract void remount() throws IOException, UnsupportedFeatureException

remounts the device.

If it doesn't throw an IOException, it was successful and the medium is accessible again.

Attention: The medium contents may have changed. (Size and flags don't change, however.)

public abstract boolean isRemoved()

is medium ejected?

public abstract void addMediumListener(MediumListener l)

add a listener

public abstract void removeMediumListener(MediumListener l)

remove a listener

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