org.entityfs
Interface EntityAcceptingEntityView<T extends EntityAcceptingEntityView<?>>

All Superinterfaces:

Comparable<EntityView>, Deletable, EntityHolder, EntityView, Lockable, Named, Observable, ReadLockable, ReadWriteLockable, ViewCapable<T>, WriteLockable

All Known Subinterfaces:

Directory, DirectoryImplementation, DirectoryView, DirectoryViewImplementation, EntityAcceptingEntity<T>, EntityAcceptingEntityImplementation<T>, EntityAcceptingEntityViewImplementation<T>, SymbolicLink, SymbolicLinkImplementation, SymbolicLinkView, SymbolicLinkViewImplementation

All Known Implementing Classes:

AbstractEntityAcceptingEntityImpl, AbstractEntityAcceptingEntityView, DirectoryImpl, DirectoryViewImpl, SymbolicLinkImpl, SymbolicLinkViewImpl

public interface EntityAcceptingEntityView<T extends EntityAcceptingEntityView<?>>
extends EntityView, ViewCapable<T>, EntityHolder

This interface defines an abstract view of an EntityAcceptingEntity. The entity-accepting entity is an abstraction of a class of entities that may have child entities, given the right conditions.

An entity-accepting entity can be dereferenced to another entity. A directory dereferences to itself and a symbolic link dereferences to its target.

Since:

1.0

Author:

Karl Gustafsson

See Also:

Entities, EntityAcceptingEntities

In_jar:

entityfs-core

Method Summary

boolean	canBeDereferenced() Can the entity-accepting entity be dereferenced.
EntityView	dereferenceOrNull() Get the entity referenced by this entity.

Methods inherited from interface org.entityfs.EntityView

canRead, canWrite, copy, copy, copyAttributes, createLock, disconnect, getCapability, getFileSystem, getLastModified, getParent, getType, getViewed, getViewedEntity, isConnected, isRootDirectory, isValid, lock, rename, setLastModified, supportsCapability, touch

Methods inherited from interface java.lang.Comparable

compareTo

Methods inherited from interface org.entityfs.event.Observable

addObserver, countObservers, deleteObserver, deleteObservers

Methods inherited from interface org.entityfs.Named

getName

Methods inherited from interface org.entityfs.lock.ReadLockable

getReadLock, isReadLockedByCurrentThread, lockForReading

Methods inherited from interface org.entityfs.Deletable

delete, isDeleted

Methods inherited from interface org.entityfs.lock.WriteLockable

getWriteLock, isWriteLockedByCurrentThread, lockForWriting

Methods inherited from interface org.entityfs.ViewCapable

getFilter, hasFilters, newView

Methods inherited from interface org.entityfs.EntityHolder

containsEntity, containsEntity, getEntityOrNull

Method Detail

dereferenceOrNull

EntityView dereferenceOrNull()
                             throws ReadLockRequiredException,
                                    AccessDeniedException,
                                    NotADirectoryException,
                                    IllegalStateException,
                                    CircularReferenceException

Get the entity referenced by this entity. For a directory (view), this returns the directory (view). For a symbolic link (view), this returns (the same view of) the link target.

This method handles symbolic links in the symbolic link target correctly. For instance, if the symbolic link l1 has the target /d1/l2/f1 and the symbolic link l2 has the target ../d2, l1 will be dereferenced to the entity with the location /d2/f1 (given that d1 and d2 are directories).

Returns:

The entity referenced by this entity

Throws:

IllegalStateException - If the view is disconnected.

ReadLockRequiredException - If the client does not have a read lock for the viewed entity.

AccessDeniedException - If the client dereferences a symbolic link and it has not execute access to a visited entity.

NotADirectoryException - If an entity in the symbolic link target path is not a directory or cannot be dereferenced to a directory.

CircularReferenceException - If the symbolic link references are circular. For instance l1 -> l2, l2 -> l1.

Locks_required:

A read lock on this entity and, for symbolic links, read locks on all entities visited while dereferencing it.

Permissions_required:

For directories: none, for symbolic links: execute access to every entity visited while dereferencing

canBeDereferenced

boolean canBeDereferenced()

Can the entity-accepting entity be dereferenced. An entity-accepting entity can be dereferenced if it is a reference to another entity (if it is a symbolic link, for instance).

Returns:

true if the entity-accepting entity can be dereferenced.

Locks_required:

None

Permissions_required:

None