FileObject

java.lang.Object
- org.das2.util.filesystem.FileObject

Direct Known Subclasses:

LocalFileObject, VFSFileObject, WebFileObject, ZipFileObject, ZipFileObject
```
public abstract class FileObject
extends java.lang.Object
```
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.

Constructor Summary

Constructors
Constructor and Description

FileObject()

Constructors
Constructor and Description
`FileObject()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract boolean`	`canRead()` returns true if the file can be read by the client.
`abstract boolean`	`exists()` returns true if the file exists.
`<T> T`	`getCapability(java.lang.Class<T> clazz)` returns extra capabilities, such as writing to the filesystem.
`java.nio.channels.ReadableByteChannel`	`getChannel()` opens a Channel, but without a monitor.
`abstract java.nio.channels.ReadableByteChannel`	`getChannel(ProgressMonitor monitor)` opens a Channel, perhaps transferring the file to a local cache first.
`abstract FileObject[]`	`getChildren()` returns objects within a folder.
`java.io.File`	`getFile()` gets a File object that can be opened by the client.
`abstract java.io.File`	`getFile(ProgressMonitor monitor)` gets a File object that can be opened by the client.
`java.io.InputStream`	`getInputStream()` opens an inputStream, perhaps transferring the file to a cache first.
`abstract java.io.InputStream`	`getInputStream(ProgressMonitor monitor)` opens an inputStream, perhaps transferring the file to a cache first.
`abstract java.lang.String`	`getNameExt()` returns the canonical name of the file within the filesystem.
`abstract FileObject`	`getParent()` returns the parent FileObject (a folder).
`abstract long`	`getSize()` returns the size of the file.
`abstract boolean`	`isData()` returns true if the file is a data file that to be used reading or writing data.
`abstract boolean`	`isFolder()` indicates the type of FileObject
`abstract boolean`	`isLocal()` returns true if the file is locally available, meaning clients can call getFile() and the readable File reference will be available in interactive time.
`abstract boolean`	`isReadOnly()` true is the file is read-only.
`abstract boolean`	`isRoot()` returns true if this is the root of the filesystem it came from.
`abstract java.util.Date`	`lastModified()` returns the Date when the file was last modified.
`boolean`	`removeLocalFile()` remove the local file in the cache, if any.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FileObject
```
public FileObject()
```
- Method Detail
  - canRead
```
public abstract boolean canRead()
```
    returns true if the file can be read by the client.
    
    Returns:
    
    true if the file can be read (see getInputStream)
  - getChildren
```
public abstract FileObject[] getChildren()
                                  throws java.io.IOException
```
    returns objects within a folder.
    
    Returns:
    
    an array of all FileObjects with the folder.
    
    Throws:
    
    java.io.IOException
  - getInputStream
```
public abstract java.io.InputStream getInputStream(ProgressMonitor monitor)
                                            throws java.io.FileNotFoundException,
                                                   java.io.IOException
```
    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
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException
  - getInputStream
```
public java.io.InputStream getInputStream()
                                   throws java.io.FileNotFoundException,
                                          java.io.IOException
```
    opens an inputStream, perhaps transferring the file to a cache first. Note no monitor is used but this may block at sub-interactive time until the file is downloaded.
    
    Returns:
    
    an InputStream
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException
  - getChannel
```
public abstract java.nio.channels.ReadableByteChannel getChannel(ProgressMonitor monitor)
                                                          throws java.io.FileNotFoundException,
                                                                 java.io.IOException
```
    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.
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException
  - getChannel
```
public java.nio.channels.ReadableByteChannel getChannel()
                                                 throws java.io.FileNotFoundException,
                                                        java.io.IOException
```
    opens a Channel, but without a monitor. Note this may block at sub-interactive time if the FileObject needs to be downloaded before access.
    
    Returns:
    
    a java.nio.channels.Channel for fast IO reads.
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException
  - getFile
```
public abstract java.io.File getFile(ProgressMonitor monitor)
                              throws java.io.FileNotFoundException,
                                     java.io.IOException
```
    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.
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException - if the file cannot be made local
    
    java.lang.NullPointerException - if the monitor is null.
  - getFile
```
public java.io.File getFile()
                     throws java.io.FileNotFoundException,
                            java.io.IOException
```
    gets a File object that can be opened by the client. Note this may block at sub-interactive time if the remote file needs to be downloaded before access.
    
    Returns:
    
    a reference to a File that can be opened.
    
    Throws:
    
    java.io.FileNotFoundException - if the file doesn't exist.
    
    java.io.IOException
  - getParent
```
public abstract FileObject getParent()
```
    returns the parent FileObject (a folder). If the fileObject is root, then null should be returned.
    
    Returns:
    
    the parent folder of this object.
  - getSize
```
public abstract long getSize()
```
    returns the size of the file.
    
    Returns:
    
    the size in bytes of the file, and -1 if the size is unknown.
  - isData
```
public abstract boolean isData()
```
    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
  - isFolder
```
public abstract boolean isFolder()
```
    indicates the type of FileObject
    
    Returns:
    
    true if the object is a folder (directory).
  - isReadOnly
```
public abstract boolean isReadOnly()
```
    true is the file is read-only.
    
    Returns:
    
    true if the file is read-only
  - isRoot
```
public abstract boolean isRoot()
```
    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.
  - isLocal
```
public abstract boolean isLocal()
```
    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
  - exists
```
public abstract boolean exists()
```
    returns true if the file exists. This may have the side effect of downloading the file.
    
    Returns:
    
    true if the file exists
  - getNameExt
```
public abstract java.lang.String getNameExt()
```
    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.
  - lastModified
```
public abstract java.util.Date lastModified()
```
    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.
  - getCapability
```
public <T> T getCapability(java.lang.Class<T> clazz)
```
    returns extra capabilities, such as writing to the filesystem.
    
    Parameters:
    
    T -
    
    Returns:
  - removeLocalFile
```
public boolean removeLocalFile()
```
    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.)

Class FileObject

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FileObject

Method Detail

canRead

getChildren

getInputStream

getInputStream

getChannel

getChannel

getFile

getFile

getParent

getSize

isData

isFolder

isReadOnly

isRoot

isLocal

exists

getNameExt

lastModified

getCapability

removeLocalFile