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## com.trolltech.qt.core
Class QAbstractFileEngine

    java.lang.Object
      com.trolltech.qt.internal.QSignalEmitterInternal
          com.trolltech.qt.QSignalEmitter
              com.trolltech.qt.QtJambiObject
                  com.trolltech.qt.core.QAbstractFileEngine

All Implemented Interfaces:
  QtJambiInterface

Direct Known Subclasses:
  QFSFileEngine

    public class QAbstractFileEngine

extends QtJambiObject

The QAbstractFileEngine class provides an abstraction for accessing the filesystem. The `QDir`, `QFile`, and `QFileInfo` classes all make use of a QAbstractFileEngine internally. If you create your own QAbstractFileEngine subclass (and register it with Qt by creating a `QAbstractFileEngineHandler` subclass), your file engine will be used when the path is one that your file engine handles.

A QAbstractFileEngine refers to one file or one directory. If the referent is a file, the `setFileName()`, `rename()`, and `remove()` functions are applicable. If the referent is a directory the `mkdir()`, `rmdir()`, and `entryList()` functions are applicable. In all cases the `caseSensitive()`, `isRelativePath()`, `fileFlags()`, `ownerId()`, `owner()`, and `fileTime()` functions are applicable.

A QAbstractFileEngine subclass can be created to do synchronous network I/O based file system operations, local file system operations, or to operate as a resource system to access file based resources.

See also:
  `QAbstractFileEngineHandler`.

Nested Class Summary
`static class` | `QAbstractFileEngine.Extension` This enum describes the types of extensions that the file engine can support.
`static class` | `QAbstractFileEngine.FileFlag` The permissions and types of a file, suitable for OR'ing together.
`static class` | `QAbstractFileEngine.FileFlags`
`static class` | `QAbstractFileEngine.FileName` These values are used to request a file name in a particular format.
`static class` | `QAbstractFileEngine.FileOwner` See also. `owner()`, `ownerId()`, and `setFileName()`.
`static class` | `QAbstractFileEngine.FileTime` These are used by the `fileTime()` function.

Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
`QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9`

Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal`

Field Summary

Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`currentSender`

Constructor Summary
`protected` | `QAbstractFileEngine()` Constructs a new QAbstractFileEngine that does not refer to any file or directory.

Method Summary
`static void` | `addSearchPathForResourceEngine(java.lang.String path)` Adds `path` to the set of paths in which Qt Jambi should search for resources.
`boolean` | `atEnd()` Returns true if the current position is at the end of the file; otherwise, returns false.
`boolean` | `caseSensitive()` Should return true if the underlying file system is case-sensitive; otherwise return false.
`boolean` | `close()` Closes the file, returning true if successful; otherwise returns false.
`boolean` | `copy(java.lang.String newName)` Copies the contents of this file to a file with the name `newName`.
`static QAbstractFileEngine` | `create(java.lang.String fileName)` Creates and returns a QAbstractFileEngine suitable for processing `fileName`.
`java.util.List` | `entryList(QDir.Filters filters, java.util.List filterNames)` Requests that a list of all the files matching the `filters` list based on the `filterNames` in the file engine's directory are returned.
`QFile.FileError` | `error()` Returns the `QFile::FileError` that resulted from the last failed operation.
`java.lang.String` | `errorString()` Returns the human-readable message appropriate to the current error reported by `error()`.
`QAbstractFileEngine.FileFlags` | `fileFlags()` This function should return the set of OR'd flags that are true for the file engine's file, and that are in the `type`'s OR'd members.
`QAbstractFileEngine.FileFlags` | `fileFlags(QAbstractFileEngine.FileFlag[] type)`
`QAbstractFileEngine.FileFlags` | `fileFlags(QAbstractFileEngine.FileFlags type)` This function should return the set of OR'd flags that are true for the file engine's file, and that are in the `type`'s OR'd members.
`java.lang.String` | `fileName()` Return the file engine's current file name in the format specified by `file`.
`java.lang.String` | `fileName(QAbstractFileEngine.FileName file)` Return the file engine's current file name in the format specified by `file`.
`QDateTime` | `fileTime(QAbstractFileEngine.FileTime time)` If `time` is `CreationTime`, return when the file was created.
`boolean` | `flush()` Flushes the open file, returning true if successful; otherwise returns false.
`int` | `handle()` Returns the native file handle for this file engine.
`boolean` | `isRelativePath()` Return true if the file referred to by this file engine has a relative path; otherwise return false.
`boolean` | `isSequential()` Returns true if the file is a sequential access device; returns false if the file is a direct access device.
`boolean` | `link(java.lang.String newName)` Creates a link from the file currently specified by `fileName()` to `newName`.
`boolean` | `mkdir(java.lang.String dirName, boolean createParentDirectories)` Requests that the directory `dirName` be created.
`boolean` | `open(QIODevice.OpenMode openMode)` Opens the file in the specified `mode`.
`boolean` | `open(QIODevice.OpenModeFlag[] openMode)`
`java.lang.String` | `owner(QAbstractFileEngine.FileOwner arg__1)` If `owner` is `OwnerUser` return the name of the user who owns the file.
`int` | `ownerId(QAbstractFileEngine.FileOwner arg__1)` If `owner` is `OwnerUser` return the ID of the user who owns the file.
`long` | `pos()` Returns the current file position.
`long` | `read(QNativePointer data, long maxlen)` Reads a number of characters from the file into `data`.
`long` | `readLine(QNativePointer data, long maxlen)` This function reads one line, terminated by a '\n' character, from the file info `data`.
`boolean` | `remove()` Requests that the file is deleted from the file system.
`static void` | `removeSearchPathForResourceEngine(java.lang.String path)` Removes `path` from the set of paths in which Qt Jambi searches for resources.
`boolean` | `rename(java.lang.String newName)` Requests that the file be renamed to `newName` in the file system.
`boolean` | `rmdir(java.lang.String dirName, boolean recurseParentDirectories)` Requests that the directory `dirName` is deleted from the file system.
`boolean` | `seek(long pos)` Sets the file position to the given `offset`.
`protected void` | `setError(QFile.FileError error, java.lang.String str)` Sets the error type to `error`, and the error string to `errorString`.
`void` | `setFileName(java.lang.String file)` Sets the file engine's file name to `file`.
`boolean` | `setPermissions(int perms)` Requests that the file's permissions be set to `perms`.
`boolean` | `setSize(long size)` Requests that the file be set to size `size`.
`long` | `size()` Returns the size of the file.
`boolean` | `supportsExtension(QAbstractFileEngine.Extension extension)` This virtual function returns true if the file engine supports `extension`; otherwise, false is returned.
`long` | `write(QNativePointer data, long len)` Writes `len` bytes from `data` to the file.

Methods inherited from class com.trolltech.qt.QtJambiObject
`dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr`

Methods inherited from class com.trolltech.qt.QSignalEmitter
`blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread`

Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`__qt_signalInitialization`

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

Methods inherited from interface com.trolltech.qt.QtJambiInterface
`disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership`

Constructor Detail

### QAbstractFileEngine

    protected QAbstractFileEngine()

  Constructs a new QAbstractFileEngine that does not refer to any file or directory.

See also:
  `setFileName()`.

Method Detail

### atEnd

    public final boolean atEnd()

  Returns true if the current position is at the end of the file; otherwise, returns false.

  This function bases its behavior on calling extension() with `AtEndExtension` . If the engine does not support this extension, false is returned.

See also:
  extension(), `supportsExtension()`, and QFile::atEnd().

### error

    public final QFile.FileError error()

  Returns the `QFile::FileError` that resulted from the last failed operation. If `QFile::UnspecifiedError` is returned, `QFile` will use its own idea of the error status.

See also:
  `setError()`, `QFile::FileError` , and `errorString()`.

### errorString

    public final java.lang.String errorString()

  Returns the human-readable message appropriate to the current error reported by `error()`. If no suitable string is available, an empty string is returned.

See also:
  `error()`.

### setError

    protected final void setError(QFile.FileError error,
                                  java.lang.String str)

  Sets the error type to `error`, and the error string to `errorString`. Call this function to set the error values returned by the higher-level classes.

See also:
  `QFile::error()`, `QIODevice::errorString()`, and `QIODevice::setErrorString()`.

### caseSensitive

    public boolean caseSensitive()

  Should return true if the underlying file system is case-sensitive; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

### close

    public boolean close()

  Closes the file, returning true if successful; otherwise returns false.

  The default implementation always returns false.

### copy

    public boolean copy(java.lang.String newName)

  Copies the contents of this file to a file with the name `newName`. Returns true on success; otherwise, false is returned.

### entryList

    public java.util.List entryList(QDir.Filters filters,
                                    java.util.List filterNames)

  Requests that a list of all the files matching the `filters` list based on the `filterNames` in the file engine's directory are returned.

  Should return an empty list if the file engine refers to a file rather than a directory, or if the directory is unreadable or does not exist or if nothing matches the specifications.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`.

### fileFlags

    public final QAbstractFileEngine.FileFlags fileFlags(QAbstractFileEngine.FileFlag[] type)

### fileFlags

    public final QAbstractFileEngine.FileFlags fileFlags()

  This function should return the set of OR'd flags that are true for the file engine's file, and that are in the `type`'s OR'd members.

  In your reimplementation you can use the `type` argument as an optimization hint and only return the OR'd set of members that are true and that match those in `type`; in other words you can ignore any members not mentioned in `type`, thus avoiding some potentially expensive lookups or system calls.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`.

### fileFlags

    public QAbstractFileEngine.FileFlags fileFlags(QAbstractFileEngine.FileFlags type)

  This function should return the set of OR'd flags that are true for the file engine's file, and that are in the `type`'s OR'd members.

  In your reimplementation you can use the `type` argument as an optimization hint and only return the OR'd set of members that are true and that match those in `type`; in other words you can ignore any members not mentioned in `type`, thus avoiding some potentially expensive lookups or system calls.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`.

### fileName

    public final java.lang.String fileName()

  Return the file engine's current file name in the format specified by `file`.

  If you don't handle some `FileName` possibilities, return the file name set in `setFileName()` when an unhandled format is requested.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, and `FileName` .

### fileName

    public java.lang.String fileName(QAbstractFileEngine.FileName file)

  Return the file engine's current file name in the format specified by `file`.

  If you don't handle some `FileName` possibilities, return the file name set in `setFileName()` when an unhandled format is requested.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, and `FileName` .

### fileTime

    public QDateTime fileTime(QAbstractFileEngine.FileTime time)

  If `time` is `CreationTime`, return when the file was created. If `time` is `ModificationTime`, return when the file was most recently modified. If `time` is `AccessTime`, return when the file was most recently accessed (e.g. read or written). If the time cannot be determined return QDateTime() (an invalid date time).

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, `QDateTime`, `QDateTime::isValid()`, and `FileTime` .

### flush

    public boolean flush()

  Flushes the open file, returning true if successful; otherwise returns false.

  The default implementation always returns false.

### handle

    public int handle()

  Returns the native file handle for this file engine. This handle must be used with care; its value and type are platform specific, and using it will most likely lead to non-portable code.

### isRelativePath

    public boolean isRelativePath()

  Return true if the file referred to by this file engine has a relative path; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`.

### isSequential

    public boolean isSequential()

  Returns true if the file is a sequential access device; returns false if the file is a direct access device.

  Operations involving `size()` and seek(int) are not valid on sequential devices.

### link

    public boolean link(java.lang.String newName)

  Creates a link from the file currently specified by `fileName()` to `newName`. What a link is depends on the underlying filesystem (be it a shortcut on Windows or a symbolic link on Unix). Returns true if successful; otherwise returns false.

### mkdir

    public boolean mkdir(java.lang.String dirName,
                         boolean createParentDirectories)

  Requests that the directory `dirName` be created. If `createParentDirectories` is true, then any sub-directories in `dirName` that don't exist must be created. If `createParentDirectories` is false then any sub-directories in `dirName` must already exist for the function to succeed. If the operation succeeds return true; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, `rmdir()`, and `isRelativePath()`.

### open

    public final boolean open(QIODevice.OpenModeFlag[] openMode)

### open

    public boolean open(QIODevice.OpenMode openMode)

  Opens the file in the specified `mode`. Returns true if the file was successfully opened; otherwise returns false.

  The `mode` is an OR combination of QIODevice::OpenMode and QIODevice::HandlingMode values.

### owner

    public java.lang.String owner(QAbstractFileEngine.FileOwner arg__1)

  If `owner` is `OwnerUser` return the name of the user who owns the file. If `owner` is `OwnerGroup` return the name of the group that own the file. If you can't determine the owner return QString().

  This virtual function must be reimplemented by all subclasses.

See also:
  `ownerId()`, `setFileName()`, and `FileOwner` .

### ownerId

    public int ownerId(QAbstractFileEngine.FileOwner arg__1)

  If `owner` is `OwnerUser` return the ID of the user who owns the file. If `owner` is `OwnerGroup` return the ID of the group that own the file. If you can't determine the owner return -2.

  This virtual function must be reimplemented by all subclasses.

See also:
  `owner()`, `setFileName()`, and `FileOwner` .

### pos

    public long pos()

  Returns the current file position.

  This is the position of the data read/write head of the file.

### read

    public long read(QNativePointer data,
                     long maxlen)

  Reads a number of characters from the file into `data`. At most `maxlen` characters will be read.

  Returns -1 if a fatal error occurs, or 0 if there are no bytes to read.

### readLine

    public long readLine(QNativePointer data,
                         long maxlen)

  This function reads one line, terminated by a '\n' character, from the file info `data`. At most `maxlen` characters will be read. The end-of-line character is included.

### remove

    public boolean remove()

  Requests that the file is deleted from the file system. If the operation succeeds return true; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, and `rmdir()`.

### rename

    public boolean rename(java.lang.String newName)

  Requests that the file be renamed to `newName` in the file system. If the operation succeeds return true; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`.

### rmdir

    public boolean rmdir(java.lang.String dirName,
                         boolean recurseParentDirectories)

  Requests that the directory `dirName` is deleted from the file system. When `recurseParentDirectories` is true, then any empty parent-directories in `dirName` must also be deleted. If `recurseParentDirectories` is false, only the `dirName` leaf-node should be deleted. In most file systems a directory cannot be deleted using this function if it is non-empty. If the operation succeeds return true; otherwise return false.

  This virtual function must be reimplemented by all subclasses.

See also:
  `setFileName()`, `remove()`, `mkdir()`, and `isRelativePath()`.

### seek

    public boolean seek(long pos)

  Sets the file position to the given `offset`. Returns true if the position was successfully set; otherwise returns false.

  The offset is from the beginning of the file, unless the file is sequential.

See also:
  `isSequential()`.

### setFileName

    public void setFileName(java.lang.String file)

  Sets the file engine's file name to `file`. This file name is the file that the rest of the virtual functions will operate on.

  This virtual function must be reimplemented by all subclasses.

See also:
  `fileName()`, and `rename()`.

### setPermissions

    public boolean setPermissions(int perms)

  Requests that the file's permissions be set to `perms`. The argument perms will be set to the OR-ed together combination of QAbstractFileEngine::FileInfo, with only the `QAbstractFileEngine::PermsMask` being honored. If the operations succceeds return true; otherwise return false;

  This virtual function must be reimplemented by all subclasses.

See also:
  `size()`.

### setSize

    public boolean setSize(long size)

  Requests that the file be set to size `size`. If `size` is larger than the current file then it is filled with 0's, if smaller it is simply truncated. If the operations succceeds return true; otherwise return false;

  This virtual function must be reimplemented by all subclasses.

See also:
  `size()`.

### size

    public long size()

  Returns the size of the file.

See also:
  `setSize()`.

### supportsExtension

    public boolean supportsExtension(QAbstractFileEngine.Extension extension)

  This virtual function returns true if the file engine supports `extension`; otherwise, false is returned. By default, no extensions are supported.

See also:
  extension().

### write

    public long write(QNativePointer data,
                      long len)

  Writes `len` bytes from `data` to the file. Returns the number of characters written on success; otherwise returns -1.

### create

    public static QAbstractFileEngine create(java.lang.String fileName)

  Creates and returns a QAbstractFileEngine suitable for processing `fileName`.

  You should not need to call this function; use `QFile`, `QFileInfo` or `QDir` directly instead.

  If you reimplemnt this function, it should only return file engines that knows how to handle `fileName`; otherwise, it should return 0.

See also:
  `QAbstractFileEngineHandler`.

### addSearchPathForResourceEngine

    public static void addSearchPathForResourceEngine(java.lang.String path)

  Adds `path` to the set of paths in which Qt Jambi should search for resources. Resources can be accessed using the "classpath:" scheme.

### removeSearchPathForResourceEngine

    public static void removeSearchPathForResourceEngine(java.lang.String path)

  Removes `path` from the set of paths in which Qt Jambi searches for resources.

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