com.trolltech.qt.core
Class QFileInfo

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QFileInfo
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable

public class QFileInfo
extends QtJambiObject
implements java.lang.Cloneable

The QFileInfo class provides system-independent file information. QFileInfo provides information about a file's name and position (path) in the file system, its access rights and whether it is a directory or symbolic link, etc. The file's size and last modified/read times are also available. QFileInfo can also be used to obtain information about a Qt resource.

A QFileInfo can point to a file with either a relative or an absolute file path. Absolute file paths begin with the directory separator "/" (or with a drive specification on Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current working directory. An example of an absolute path is the string "/tmp/quartz". A relative path might look like "src/fatlib". You can use the function isRelative() to check whether a QFileInfo is using a relative or an absolute file path. You can call the function makeAbsolute() to convert a relative QFileInfo's path to an absolute path.

The file that the QFileInfo works on is set in the constructor or later with setFile(). Use exists() to see if the file exists and size() to get its size.

The file's type is obtained with isFile(), isDir() and isSymLink(). The symLinkTarget() function provides the name of the file the symlink points to.

On Unix (including Mac OS X), the symlink has the same size() has the file it points to, because Unix handles symlinks transparently; similarly, opening a symlink using QFile effectively opens the link's target. For example:

        QFileInfo info1 = new QFileInfo("/home/bob/bin/untabify");
        info1.isSymLink();          // returns true
        info1.absoluteFilePath();   // returns "/home/bob/bin/untabify"
        info1.size();               // returns 56201
        info1.symLinkTarget();      // returns "/opt/pretty++/bin/untabify"

        QFileInfo info2 = new QFileInfo(info1.symLinkTarget());
        info1.isSymLink();          // returns false
        info1.absoluteFilePath();   // returns "/opt/pretty++/bin/untabify"
        info1.size();               // returns 56201
On Windows, symlinks (shortcuts) are .lnk files. The reported size() is that of the symlink (not the link's target), and opening a symlink using QFile opens the .lnk file. For example:
        QFileInfo info1 = new QFileInfo("C:\\Documents and Settings\\Bob\\untabify.lnk");
        info1.isSymLink();          // returns true
        info1.absoluteFilePath();   // returns "C:/Documents and Settings/Bob/untabify.lnk"
        info1.size();               // returns 743
        info1.symLinkTarget();      // returns "C:/Pretty++/untabify"

        QFileInfo info2 = new QFileInfo(info1.symLinkTarget());
        info1.isSymLink();          // returns false
        info1.absoluteFilePath();   // returns "C:/Pretty++/untabify"
        info1.size();               // returns 63942
Elements of the file's name can be extracted with path() and fileName(). The fileName()'s parts can be extracted with baseName(), suffix() or completeSuffix(). QFileInfo objects to directories created by Qt classes will not have a trailing file separator. If you wish to use trailing separators in your own file info objects, just append one to the file name given to the constructors or setFile().

The file's dates are returned by created(), lastModified() and lastRead(). Information about the file's access permissions is obtained with isReadable(), isWritable() and isExecutable(). The file's ownership is available from owner(), ownerId(), group() and groupId(). You can examine a file's permissions and ownership in a single statement using the permission() function.

Performance Issues

Some of QFileInfo's functions query the file system, but for performance reasons, some functions only operate on the file name itself. For example: To return the absolute path of a relative file name, absolutePath() has to query the file system. The path() function, however, can work on the file name directly, and so it is faster.

Note: To speed up performance, QFileInfo caches information about the file.

To speed up performance, QFileInfo caches information about the file. Because files can be changed by other users or programs, or even by other parts of the same program, there is a function that refreshes the file information: refresh(). If you want to switch off a QFileInfo's caching and force it to access the file system every time you request information from it call setCaching(false).

See also:
QDir, and QFile.


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, 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
QFileInfo()
          Constructs an empty QFileInfo object.
QFileInfo(QDir dir, java.lang.String file)
          Constructs a new QFileInfo that gives information about the given file in the directory dir.
QFileInfo(QFile file)
          Constructs a new QFileInfo that gives information about file file.
QFileInfo(QFileInfo fileinfo)
          Constructs a new QFileInfo that is a copy of the given fileinfo.
QFileInfo(java.lang.String file)
          Constructs a new QFileInfo that gives information about the given file.
 
Method Summary
 QDir absoluteDir()
          Returns the file's absolute path as a QDir object.
 java.lang.String absoluteFilePath()
          Returns an absolute path including the file name.
 java.lang.String absolutePath()
          Returns a file's path absolute path.
 java.lang.String baseName()
          Returns the base name of the file without the path.
 java.lang.String bundleName()
          Returns the name of the bundle.
 boolean caching()
          Returns true if caching is enabled; otherwise returns false.
 java.lang.String canonicalFilePath()
          Returns the canonical path including the file name, i.
 java.lang.String canonicalPath()
          Returns the file's path canonical path (excluding the file name), i.
 QFileInfo clone()
          This method is reimplemented for internal reasons
 java.lang.String completeBaseName()
          Returns the complete base name of the file without the path.
 java.lang.String completeSuffix()
          Returns the complete suffix of the file.
 QDateTime created()
          Returns the date and time when the file was created.
 QDir dir()
          Returns the path of the object's parent directory as a QDir object.
 boolean exists()
          Returns true if the file exists; otherwise returns false.
 java.lang.String fileName()
          Returns the name of the file, excluding the path.
 java.lang.String filePath()
          Returns the file name, including the path (which may be absolute or relative).
 java.lang.String group()
          Returns the group of the file.
 int groupId()
          Returns the id of the group the file belongs to.
 boolean isAbsolute()
          Returns true if the file path name is absolute, otherwise returns false if the path is relative.
 boolean isBundle()
          Returns true if this object points to a bundle or to a symbolic link to a bundle on Mac OS X; otherwise returns false.
 boolean isDir()
          Returns true if this object points to a directory or to a symbolic link to a directory; otherwise returns false.
 boolean isExecutable()
          Returns true if the file is executable; otherwise returns false.
 boolean isFile()
          Returns true if this object points to a file or to a symbolic link to a file.
 boolean isHidden()
          Returns true if this is a `hidden' file; otherwise returns false.
 boolean isReadable()
          Returns true if the user can read the file; otherwise returns false.
 boolean isRelative()
          Returns true if the file path name is relative, otherwise returns false if the path is absolute (e.
 boolean isRoot()
          Returns true if the object points to a directory or to a symbolic link to a directory, and that directory is the root directory; otherwise returns false.
 boolean isSymLink()
          Returns true if this object points to a symbolic link (or to a shortcut on Windows); otherwise returns false.
 boolean isWritable()
          Returns true if the user can write to the file; otherwise returns false.
 QDateTime lastModified()
          Returns the date and time when the file was last modified.
 QDateTime lastRead()
          Returns the date and time when the file was last read (accessed).
 boolean makeAbsolute()
          Converts the file's path to an absolute path if it is not already in that form.
 java.lang.String owner()
          Returns the owner of the file.
 int ownerId()
          Returns the id of the owner of the file.
 java.lang.String path()
          Returns the file's path.
 boolean permission(QFile.Permission[] permissions)
          This is an overloaded method provided for convenience.
 boolean permission(QFile.Permissions permissions)
          Tests for file permissions.
 QFile.Permissions permissions()
          Returns the complete OR-ed together combination of QFile.:Permissions for the file.
 void refresh()
          Refreshes the information about the file, i.e.
 void setCaching(boolean on)
          If enable is true, enables caching of file information.
 void setFile(QDir dir, java.lang.String file)
          This is an overloaded member function, provided for convenience.
 void setFile(QFile file)
          This is an overloaded member function, provided for convenience.
 void setFile(java.lang.String file)
          Sets the file that the QFileInfo provides information about to file.
 long size()
          Returns the file size in bytes.
 java.lang.String suffix()
          Returns the suffix of the file.
 java.lang.String symLinkTarget()
          Returns the absolute path to the file or directory a symlink (or shortcut on Windows) points to, or a an empty string if the object isn't a symbolic link.
 
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
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QFileInfo

public QFileInfo()
Constructs an empty QFileInfo object.

Note that an empty QFileInfo object contain no file reference.

See also:
setFile().


QFileInfo

public QFileInfo(QDir dir,
                 java.lang.String file)
Constructs a new QFileInfo that gives information about the given file in the directory dir.

If dir has a relative path, the QFileInfo will also have a relative path.

See also:
isRelative().


QFileInfo

public QFileInfo(QFile file)
Constructs a new QFileInfo that gives information about file file.

If the file has a relative path, the QFileInfo will also have a relative path.

See also:
isRelative().


QFileInfo

public QFileInfo(QFileInfo fileinfo)
Constructs a new QFileInfo that is a copy of the given fileinfo.


QFileInfo

public QFileInfo(java.lang.String file)
Constructs a new QFileInfo that gives information about the given file. The file can also include an absolute or relative path.

See also:
setFile(), isRelative(), QDir::setCurrent(), and QDir::isRelativePath().

Method Detail

absoluteDir

public final QDir absoluteDir()
Returns the file's absolute path as a QDir object.

See also:
dir(), filePath(), fileName(), and isRelative().


absoluteFilePath

public final java.lang.String absoluteFilePath()
Returns an absolute path including the file name.

The absolute path name consists of the full path and the file name. On Unix this will always begin with the root, '/', directory. On Windows this will always begin 'D:/' where D is a drive letter, except for network shares that are not mapped to a drive letter, in which case the path will begin '//sharename/'. QFileInfo will uppercase drive letters. Note that QDir does not do this. The code snippet below shows this.Error parsing snippet. This function returns the same as filePath(), unless isRelative() is true. In contrast to canonicalFilePath(), symbolic links or redundant "." or ".." elements are not necessarily removed.

If the QFileInfo is empty it returns QDir::currentPath().

See also:
filePath(), canonicalFilePath(), and isRelative().


absolutePath

public final java.lang.String absolutePath()
Returns a file's path absolute path. This doesn't include the file name.

On Unix the absolute path will always begin with the root, '/', directory. On Windows this will always begin 'D:/' where D is a drive letter, except for network shares that are not mapped to a drive letter, in which case the path will begin '//sharename/'.

This function returns the same as filePath(), unless isRelative() is true. In contrast to canonicalPath() symbolic links or redundant "." or ".." elements are not necessarily removed.

Warning: If the QFileInfo object was created with an empty QString, the behavior of this function is undefined.

See also:
absoluteFilePath(), path(), canonicalPath(), fileName(), and isRelative().


baseName

public final java.lang.String baseName()
Returns the base name of the file without the path.

The base name consists of all characters in the file up to (but not including) the first '.' character.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        String base = fi.baseName();  // base = "archive"
The base name of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").

See also:
fileName(), suffix(), completeSuffix(), and completeBaseName().


bundleName

public final java.lang.String bundleName()
Returns the name of the bundle.

On Mac OS X this returns the proper localized name for a bundle if the path isBundle(). On all other platforms an empty QString is returned.

Example:

        QFileInfo fi = new QFileInfo("/Applications/Safari.app");
        String bundle = fi.bundleName();                // name = "Safari"

See also:
isBundle(), filePath(), baseName(), and extension().


caching

public final boolean caching()
Returns true if caching is enabled; otherwise returns false.

See also:
setCaching(), and refresh().


canonicalFilePath

public final java.lang.String canonicalFilePath()
Returns the canonical path including the file name, i. . an absolute path without symbolic links or redundant "." or ".." elements.

If the file does not exist, canonicalFilePath() returns an empty string.

See also:
filePath(), absoluteFilePath(), and dir().


canonicalPath

public final java.lang.String canonicalPath()
Returns the file's path canonical path (excluding the file name), i. . an absolute path without symbolic links or redundant "." or ".." elements.

If the file does not exist, canonicalPath() returns an empty string.

See also:
path(), and absolutePath().


completeBaseName

public final java.lang.String completeBaseName()
Returns the complete base name of the file without the path.

The complete base name consists of all characters in the file up to (but not including) the last '.' character.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        String base = fi.completeBaseName();  // base = "archive.tar"

See also:
fileName(), suffix(), completeSuffix(), and baseName().


completeSuffix

public final java.lang.String completeSuffix()
Returns the complete suffix of the file.

The complete suffix consists of all characters in the file after (but not including) the first '.'.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        String ext = fi.completeSuffix();  // ext = "tar.gz"

See also:
fileName(), suffix(), baseName(), and completeBaseName().


created

public final QDateTime created()
Returns the date and time when the file was created.

On most Unix systems, this function returns the time of the last status change. A status change occurs when the file is created, but it also occurs whenever the user writes or sets inode information (for example, changing the file permissions).

If neither creation time nor "last status change" time are not available, returns the same as lastModified().

See also:
lastModified(), and lastRead().


dir

public final QDir dir()
Returns the path of the object's parent directory as a QDir object.

Note: The QDir returned always corresponds to the object's parent directory, even if the QFileInfo represents a directory.

For each of the follwing, dir() returns a QDir for "~/examples/191697".

The following code example is written in c++.

    QFileInfo fileInfo1("~/examples/191697/.");
    QFileInfo fileInfo2("~/examples/191697/..");
    QFileInfo fileInfo3("~/examples/191697/main.cpp");
For each of the follwing, dir() returns a QDir for ".".

The following code example is written in c++.
    
    QFileInfo fileInfo4(".");
    QFileInfo fileInfo5("..");
    QFileInfo fileInfo6("main.cpp");

See also:
absolutePath(), filePath(), fileName(), isRelative(), and absoluteDir().


exists

public final boolean exists()
Returns true if the file exists; otherwise returns false.

Note: If the file is a symlink that points to a non existing file, false is returned.


fileName

public final java.lang.String fileName()
Returns the name of the file, excluding the path.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        String name = fi.fileName();                // name = "archive.tar.gz"
Note that, if this QFileInfo object is given a path ending in a slash, the name of the file is considered empty.

See also:
isRelative(), filePath(), baseName(), and extension().


filePath

public final java.lang.String filePath()
Returns the file name, including the path (which may be absolute or relative).

See also:
absoluteFilePath(), canonicalFilePath(), and isRelative().


group

public final java.lang.String group()
Returns the group of the file. On Windows, on systems where files do not have groups, or if an error occurs, an empty string is returned.

This function can be time consuming under Unix (in the order of milliseconds).

See also:
groupId(), owner(), and ownerId().


groupId

public final int groupId()
Returns the id of the group the file belongs to.

On Windows and on systems where files do not have groups this function always returns (uint) -2.

See also:
group(), owner(), and ownerId().


isAbsolute

public final boolean isAbsolute()
Returns true if the file path name is absolute, otherwise returns false if the path is relative.

See also:
isRelative().


isBundle

public final boolean isBundle()
Returns true if this object points to a bundle or to a symbolic link to a bundle on Mac OS X; otherwise returns false.

See also:
isDir(), isSymLink(), and isFile().


isDir

public final boolean isDir()
Returns true if this object points to a directory or to a symbolic link to a directory; otherwise returns false.

See also:
isFile(), isSymLink(), and isBundle().


isExecutable

public final boolean isExecutable()
Returns true if the file is executable; otherwise returns false.

See also:
isReadable(), isWritable(), and permission().


isFile

public final boolean isFile()
Returns true if this object points to a file or to a symbolic link to a file. Returns false if the object points to something which isn't a file, such as a directory.

See also:
isDir(), isSymLink(), and isBundle().


isHidden

public final boolean isHidden()
Returns true if this is a `hidden' file; otherwise returns false.

Note: This function returns true for the special entries "." and ".." on Unix, even though QDir::entryList threats them as shown.


isReadable

public final boolean isReadable()
Returns true if the user can read the file; otherwise returns false.

See also:
isWritable(), isExecutable(), and permission().


isRelative

public final boolean isRelative()
Returns true if the file path name is relative, otherwise returns false if the path is absolute (e. . under Unix a path is absolute if it begins with a "/").

See also:
isAbsolute().


isRoot

public final boolean isRoot()
Returns true if the object points to a directory or to a symbolic link to a directory, and that directory is the root directory; otherwise returns false.


isSymLink

public final boolean isSymLink()
Returns true if this object points to a symbolic link (or to a shortcut on Windows); otherwise returns false.

On Unix (including Mac OS X), opening a symlink effectively opens the link's target. On Windows, it opens the .lnk file itself.

Example:

        QFileInfo info = new QFileInfo(fileName);
        if (info.isSymLink())
            fileName = info.symLinkTarget();
Note: If the symlink points to a non existing file, exists() returns false.

See also:
isFile(), isDir(), and symLinkTarget().


isWritable

public final boolean isWritable()
Returns true if the user can write to the file; otherwise returns false.

See also:
isReadable(), isExecutable(), and permission().


lastModified

public final QDateTime lastModified()
Returns the date and time when the file was last modified.

See also:
created(), and lastRead().


lastRead

public final QDateTime lastRead()
Returns the date and time when the file was last read (accessed).

On platforms where this information is not available, returns the same as lastModified().

See also:
created(), and lastModified().


makeAbsolute

public final boolean makeAbsolute()
Converts the file's path to an absolute path if it is not already in that form. Returns true to indicate that the path was converted; otherwise returns false to indicate that the path was already absolute.

See also:
filePath(), and isRelative().


owner

public final java.lang.String owner()
Returns the owner of the file. On systems where files do not have owners, or if an error occurs, an empty string is returned.

This function can be time consuming under Unix (in the order of milliseconds).

See also:
ownerId(), group(), and groupId().


ownerId

public final int ownerId()
Returns the id of the owner of the file.

On Windows and on systems where files do not have owners this function returns ((uint) -2).

See also:
owner(), group(), and groupId().


path

public final java.lang.String path()
Returns the file's path. This doesn't include the file name.

Note that, if this QFileInfo object is given a path ending in a slash, the name of the file is considered empty and this function will return the entire path.

See also:
filePath(), absolutePath(), canonicalPath(), dir(), fileName(), and isRelative().


permission

public final boolean permission(QFile.Permission[] permissions)
This is an overloaded method provided for convenience.


permission

public final boolean permission(QFile.Permissions permissions)
Tests for file permissions. The permissions argument can be several flags of type QFile::Permissions OR-ed together to check for permission combinations.

On systems where files do not have permissions this function always returns true.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        QFile.Permissions permissions1
            = new QFile.Permissions(QFile.Permission.WriteUser, QFile.Permission.ReadGroup);
        if (fi.permission(permissions1))
            System.out.println("I can change the file; my group can read the file");
        QFile.Permissions permissions2
            = new QFile.Permissions(QFile.Permission.WriteGroup, QFile.Permission.WriteOther);
        if (fi.permission(permissions2))
            System.out.println("The group or others can change the file");

See also:
isReadable(), isWritable(), and isExecutable().


permissions

public final QFile.Permissions permissions()
Returns the complete OR-ed together combination of QFile.:Permissions for the file.


refresh

public final void refresh()
Refreshes the information about the file, i.e. reads in information from the file system the next time a cached property is fetched.

Note: On Windows CE, there might be a delay for the file system driver to detect changes on the file.


setCaching

public final void setCaching(boolean on)
If enable is true, enables caching of file information. If enable is false caching is disabled.

When caching is enabled, QFileInfo reads the file information from the file system the first time it's needed, but generally not later.

Caching is enabled by default.

See also:
refresh(), and caching().


setFile

public final void setFile(QDir dir,
                          java.lang.String file)
This is an overloaded member function, provided for convenience.

Sets the file that the QFileInfo provides information about to file in directory dir.

If file includes a relative path, the QFileInfo will also have a relative path.

See also:
isRelative().


setFile

public final void setFile(QFile file)
This is an overloaded member function, provided for convenience.

Sets the file that the QFileInfo provides information about to file.

If file includes a relative path, the QFileInfo will also have a relative path.

See also:
isRelative().


setFile

public final void setFile(java.lang.String file)
Sets the file that the QFileInfo provides information about to file.

The file can also include an absolute or relative file path. Absolute paths begin with the directory separator (e.g. "/" under Unix) or a drive specification (under Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current directory.

Example:

    String absolute = "/local/bin";
    String relative = "local/bin";
    QFileInfo absFile = new QFileInfo(absolute);
    QFileInfo relFile = new QFileInfo(relative);

    QDir.setCurrent(QDir.rootPath());
    // absFile and relFile now point to the same file

    QDir.setCurrent("/tmp");
    // absFile now points to "/local/bin",
    // while relFile points to "/tmp/local/bin"

See also:
isFile(), isRelative(), QDir::setCurrent(), and QDir::isRelativePath().


size

public final long size()
Returns the file size in bytes. If the file does not exist or cannot be fetched, 0 is returned.

See also:
exists().


suffix

public final java.lang.String suffix()
Returns the suffix of the file.

The suffix consists of all characters in the file after (but not including) the last '.'.

Example:

        QFileInfo fi = new QFileInfo("/tmp/archive.tar.gz");
        String ext = fi.suffix();  // ext = "gz"
The suffix of a file is computed equally on all platforms, independent of file naming conventions (e.g., ".bashrc" on Unix has an empty base name, and the suffix is "bashrc").

See also:
fileName(), completeSuffix(), baseName(), and completeBaseName().


symLinkTarget

public final java.lang.String symLinkTarget()
Returns the absolute path to the file or directory a symlink (or shortcut on Windows) points to, or a an empty string if the object isn't a symbolic link.

This name may not represent an existing file; it is only a string. QFileInfo::exists() returns true if the symlink points to an existing file.

See also:
exists(), isSymLink(), isDir(), and isFile().


clone

public QFileInfo clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object