Class ProcessBuilder.Redirect

java.lang.Object

java.lang.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:

the special value Redirect.PIPE
the special value Redirect.INHERIT
the special value Redirect.DISCARD
a redirection to read from a file, created by an invocation of Redirect.from(File)
a redirection to write to a file, created by an invocation of Redirect.to(File)
a redirection to append to a file, created by an invocation of Redirect.appendTo(File)

Each of the above categories has an associated unique Type.

Since:: 1.7

Nested Class Summary

Modifier and Type	Class	Description
`static enum`	`ProcessBuilder.Redirect.Type`	The type of a `ProcessBuilder.Redirect`.

Field Summary

Modifier and Type	Field	Description
`static final ProcessBuilder.Redirect`	`DISCARD`	Indicates that subprocess output will be discarded.
`static final ProcessBuilder.Redirect`	`INHERIT`	Indicates that subprocess I/O source or destination will be the same as those of the current process.
`static final ProcessBuilder.Redirect`	`PIPE`	Indicates that subprocess I/O will be connected to the current Java process over a pipe.

Method Summary

Modifier and Type	Method	Description
`static ProcessBuilder.Redirect`	`appendTo(File file)`	Returns a redirect to append to the specified file.
`boolean`	`equals(Object obj)`	Compares the specified object with this `Redirect` for equality.
`File`	`file()`	Returns the `File` source or destination associated with this redirect, or `null` if there is no such file.
`static ProcessBuilder.Redirect`	`from(File file)`	Returns a redirect to read from the specified file.
`int`	`hashCode()`	Returns a hash code value for this `Redirect`.
`static ProcessBuilder.Redirect`	`to(File file)`	Returns a redirect to write to the specified file.
`abstract ProcessBuilder.Redirect.Type`	`type()`	Returns the type of this `Redirect`.

Methods declared in class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()`	Returns a string representation of the object.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Field Details

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() != null && // is the filename appropriate for the operating system
    Redirect.DISCARD.type() == Redirect.Type.WRITE;

Since:: 9

Method Details

type

public abstract ProcessBuilder.Redirect.Type type()

Returns the type of this Redirect.

Returns:: the type of this Redirect

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:

hashCode

public int hashCode()

Returns a hash code value for this Redirect.

Overrides:

hashCode in class Object

Returns:

a hash code value for this Redirect

See Also:

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