Module java.base
Package java.lang

Class ProcessBuilder.Redirect

  • Enclosing class:
    ProcessBuilder
    public abstract static class ProcessBuilder.Redirect
extends Object
    Represents a source of subprocess input or a destination of subprocess output. Each Redirect instance is one of the following:

    Each of the above categories has an associated unique Type.

    Since:
    1.7

    • Field Detail

      • PIPE

        public static final ProcessBuilder.Redirect PIPE
        Indicates that subprocess I/O will be connected to the current Java process over a pipe. This is the default handling of subprocess standard I/O.

        It will always be true that 

         
 Redirect.PIPE.file() == null &&
 Redirect.PIPE.type() == Redirect.Type.PIPE

      • INHERIT

        public static final ProcessBuilder.Redirect INHERIT
        Indicates that subprocess I/O source or destination will be the same as those of the current process. This is the normal behavior of most operating system command interpreters (shells).

        It will always be true that 

         
 Redirect.INHERIT.file() == null &&
 Redirect.INHERIT.type() == Redirect.Type.INHERIT

      • DISCARD

        public static final ProcessBuilder.Redirect DISCARD
        Indicates that subprocess output will be discarded. A typical implementation discards the output by writing to an operating system specific "null file".

        It will always be true that 

         
 Redirect.DISCARD.file() is the filename appropriate for the operating system
 and may be null &&
 Redirect.DISCARD.type() == Redirect.Type.WRITE

        Since:
        9

    • Method Detail

      • file

        public File file()
        Returns the File source or destination associated with this redirect, or null if there is no such file.
        Returns:
        the file associated with this redirect, or null if there is no such file

      • from

        public static ProcessBuilder.Redirect from​(File file)
        Returns a redirect to read from the specified file.

        It will always be true that 

         
 Redirect.from(file).file() == file &&
 Redirect.from(file).type() == Redirect.Type.READ

        Parameters:
        file - The File for the Redirect.
        Returns:
        a redirect to read from the specified file

      • to

        public static ProcessBuilder.Redirect to​(File file)
        Returns a redirect to write to the specified file. If the specified file exists when the subprocess is started, its previous contents will be discarded.

        It will always be true that 

         
 Redirect.to(file).file() == file &&
 Redirect.to(file).type() == Redirect.Type.WRITE

        Parameters:
        file - The File for the Redirect.
        Returns:
        a redirect to write to the specified file

      • appendTo

        public static ProcessBuilder.Redirect appendTo​(File file)
        Returns a redirect to append to the specified file. Each write operation first advances the position to the end of the file and then writes the requested data. Whether the advancement of the position and the writing of the data are done in a single atomic operation is system-dependent and therefore unspecified.

        It will always be true that 

         
 Redirect.appendTo(file).file() == file &&
 Redirect.appendTo(file).type() == Redirect.Type.APPEND

        Parameters:
        file - The File for the Redirect.
        Returns:
        a redirect to append to the specified file

      • equals

        public boolean equals​(Object obj)
        Compares the specified object with this Redirect for equality. Returns true if and only if the two objects are identical or both objects are Redirect instances of the same type associated with non-null equal File instances.
        Overrides:
        equals in class Object
        Parameters:
        obj - the reference object with which to compare.
        Returns:
        true if this object is the same as the obj argument; false otherwise.
        See Also:
        Object.hashCode(), HashMap