org.das2.util.filesystem.FileObject

Class for describing and accessing files in file systems. This is similar to java.io.File, except that it can describe files on remote file systems like an ftp site.

Note: this is modelled after the NetBeans fileSystem FileObject, with the thought that we might use it later.

FileObject( )

canRead

canRead( ) → boolean

returns true if the file can be read by the client.

Returns:

true if the file can be read (see getInputStream)

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exists

exists( ) → boolean

returns true if the file exists. This may have the side effect of downloading the file.

Returns:

true if the file exists

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getCapability

getCapability( java.lang.Class clazz ) → Object

returns extra capabilities, such as writing to the filesystem.

Parameters

clazz - a java.lang.Class

Returns:

an Object

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getChannel

getChannel( ProgressMonitor monitor ) → ReadableByteChannel

opens a Channel, perhaps transferring the file to a local cache first. monitor is used to monitor the download.

Parameters

monitor - for monitoring the download. The monitor won't be used when the access is immediate, for example with local FileObjects.

Returns:

a java.nio.channels.Channel for fast IO reads.

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getChannel( ) → ReadableByteChannel

getChildren

getChildren( ) → FileObject[]

returns objects within a folder.

Returns:

an array of all FileObjects with the folder.

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getFile

getFile( ProgressMonitor monitor ) → File

gets a File object that can be opened by the client. This may download a remote file, so a progress monitor can be used to monitor the download.

Parameters

monitor - for monitoring the download. The monitor won't be used when the access is immediate, for example with local FileObjects.

Returns:

a reference to a File that can be opened.

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getFile( ) → File

getInputStream

getInputStream( ProgressMonitor monitor ) → InputStream

opens an inputStream, perhaps transferring the file to a cache first.

Parameters

monitor - for monitoring the download. The monitor won't be used when the access is immediate, for example with local FileObjects.

Returns:

an InputStream

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getInputStream( ) → InputStream

getNameExt

getNameExt( ) → String

returns the canonical name of the file within the filesystem. For example, in the local filesystem /mnt/data/steven/, /mnt/data/steven/jan/01.dat would be /jan/01.dat. For example, /a/b/c.dat.

Returns:

the name of the file within the FileSystem.

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getParent

getParent( ) → FileObject

returns the parent FileObject (a folder). If the fileObject is root, then null should be returned.

Returns:

the parent folder of this object.

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getSize

getSize( ) → long

returns the size of the file.

Returns:

the size in bytes of the file, and -1 if the size is unknown.

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isData

isData( ) → boolean

returns true if the file is a data file that to be used reading or writing data. (And not a folder.)

Returns:

true if the file is a data file

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isFolder

isFolder( ) → boolean

indicates the type of FileObject

Returns:

true if the object is a folder (directory).

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isLocal

isLocal( ) → boolean

returns true if the file is locally available, meaning clients can call getFile() and the readable File reference will be available in interactive time. Note that isLocal does not imply exists(). Also, This may result in side effects such as a website hit.

Returns:

true if the file is locally available and fresh

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isReadOnly

isReadOnly( ) → boolean

true is the file is read-only.

Returns:

true if the file is read-only

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isRoot

isRoot( ) → boolean

returns true if this is the root of the filesystem it came from.

Returns:

true if this is the root of the filesystem it came from.

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lastModified

lastModified( ) → Date

returns the Date when the file was last modified. or new Date(0L) if the date is not available.

Returns:

the last modified Date, or new Date(0) if it is not available.

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removeLocalFile

removeLocalFile( ) → boolean

remove the local file in the cache, if any. This can/will be overriden by other filesystems.

Returns:

true if the action was handled. (Local files are not deleted.)

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