Package com.xmlmind.util

Class SystemUtil

  • public final class SystemUtil
extends Object
    A collection of utility functions (static methods) which complements what's found in java.lang.System.

    • Method Detail

      • homeDir

        public static File homeDir()
        Returns the absolute, canonical directory corresponding to system property user.home (that is, the home directory of the user of this application) if this directory exists. Returns null otherwise.

      • currentWorkingDir

        public static File currentWorkingDir()
        Returns the absolute, canonical directory corresponding to system property user.dir (that is, the current working directory) if this directory exists. Returns null otherwise.

      • setUserPreferencesDir

        public static void setUserPreferencesDir​(File dir)
        Specify a custom user preferences directory.
        Parameters:
        dir - the custom user preferences directory The fact that dir exists or is a directory is not checked.

        Specify null to revert to the default user preferences directory of this application.

        See Also:
        userPreferencesDir()

      • userPreferencesDir

        public static File userPreferencesDir()
        Returns the user preferences directory of this application. More precisely:
        See Also:
        defaultUserPreferencesDir()

      • userPreferencesDir

        public static File userPreferencesDir​(String vendor,
                                      String product,
                                      String app)
        Returns the directory used to store the preferences of specified application.

        Example: vendor="XMLmind", product="XMLEditor", app="xxe":

        • $HOME/.xxe/ on Linux, FreeBSD, etc.
        • $HOME/Library/Application Support/XMLmind/XMLEditor on macOS.
        • %APPDATA%\XMLmind\XMLEditor\ on Windows.
        Parameters:
        vendor - name of the vendor of the product
        product - official product name
        app - nickname of the product
        Returns:
        the user preferences directory.

        Returns null if system property user.home is not set or does not specify an existing directory.

        The returned canonical file may specify a directory which does not exist yet and/or which may be impossible to create.

      • defaultEncoding

        public static String defaultEncoding()
        Returns the default character encoding for this platform.
        Returns:
        canonical name of default charset for this platform

      • listEncodings

        public static String[] listEncodings()
        Returns the canonical names of all the charsets supported by the Java runtime. The returned array is sorted.

      • javaVersionNumber

        public static VersionNumber javaVersionNumber()
        Returns the version number of current JavaTM runtime.

        If the system property "java.version" does not exist or cannot be parsed, returns 1.8.0.

      • hasJavaFX

        public static final boolean hasJavaFX()
        Returns true if the current Java runtime has a usable, found by default in the CLASSPATH, JavaFX runtime.
        • As of Java 1.8.0_40, Oracle Java includes JavaFX.
        • As of Java 11, Oracle Java no longer includes JavaFX.
        • OpenJDK does not include JavaFX.

      • osVersionNumber

        public static VersionNumber osVersionNumber()
        Returns the version number of the operating system.

        If the system property "os.version" does not exist or cannot be parsed, returns null.

      • shellStart

        public static Process shellStart​(String command,
                                 String[] envp,
                                 File dir)
                          throws IOException
        Executes a command using the standard shell of the platform. Unlike shellExec(java.lang.String, java.lang.String[]), does not wait until the command is completed.
        Parameters:
        command - the shell command to be executed
        envp - array of pairs: environment variable name/value. Specify null to inherit the environment settings of the current process.
        dir - the working directory of the subprocess. Specify null to inherit the working directory of the current process.
        Returns:
        the process of the shell
        Throws:
        IOException - if an I/O error occurs

      • shellExec

        public static int shellExec​(String command,
                            String[] envp,
                            File dir,
                            String[] capture)
                     throws IOException,
                            InterruptedException
        Executes a command using the standard shell of the platform, capturing output to System.out and System.err.
        Parameters:
        command - the shell command to be executed
        envp - array of pairs: environment variable name/value. Specify null to inherit the environment settings of the current process.
        dir - the working directory of the subprocess. Specify null to inherit the working directory of the current process.
        capture - output to System.out is captured and saved to capture[0] and output to System.err is captured and saved to capture[1]. May not be null.
        Returns:
        the exit status returned by the shell
        Throws:
        IOException - if an I/O error occurs
        InterruptedException - if the current thread is interrupted by another thread while it is waiting the completion of the shell command

      • captureOutput

        public static int captureOutput​(Process process,
                                String[] capture)
                         throws InterruptedException
        Captures output of specified newly started process (see shellStart(String)).
        Parameters:
        process - newly started process
        capture - output to System.out is captured and saved to capture[0] and output to System.err is captured and saved to capture[1]. May not be null.
        Returns:
        exit status of process
        Throws:
        InterruptedException - if the current thread is interrupted by another thread while it is waiting the completion of the process

      • shellExec

        public static int shellExec​(String command,
                            String[] envp,
                            File dir,
                            Console console)
                     throws IOException,
                            InterruptedException
        Executes a command using the standard shell of the platform.
        Parameters:
        command - the shell command to be executed
        envp - array of pairs: environment variable name/value. Specify null to inherit the environment settings of the current process.
        dir - the working directory of the subprocess. Specify null to inherit the working directory of the current process.
        console - output to System.out is displayed by this console as Console.MessageType.INFO messages and output to System.err is is displayed by this console as Console.MessageType.ERROR messages. May be null.
        Returns:
        the exit status returned by the shell
        Throws:
        IOException - if an I/O error occurs
        InterruptedException - if the current thread is interrupted by another thread while it is waiting the completion of the shell command

      • captureOutput

        public static int captureOutput​(Process process,
                                Console console)
                         throws InterruptedException
        Captures output of specified newly started process (see shellStart(String)).
        Parameters:
        process - newly started process
        console - output to System.out is captured and displayed as INFO messages on this console and output to System.err is captured and sisplayed as ERROR messages on this console. May be null.
        Returns:
        exit status of process
        Throws:
        InterruptedException - if the current thread is interrupted by another thread while it is waiting the completion of the process

      • findAppInPath

        public static File findAppInPath​(String appName)
        Searches specified application using the PATH environment variable.
        Parameters:
        appName - the basename of the executable file of the application.

        On Windows, this basename may have no extension. In such case, all the extensions found in the the PATHEXT environment variable (".exe", ".bat", etc), are tried in turn.

        Returns:
        the absolute filename of the application if found; null otherwise.