groovy.ui

## Class SystemOutputInterceptor

- java.lang.Object
- - java.io.OutputStream
  - - java.io.FilterOutputStream
    - - groovy.ui.SystemOutputInterceptor

- All Implemented Interfaces:
    java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

      public class SystemOutputInterceptor
      extends java.io.FilterOutputStream

  Intercepts System.out/System.err. Implementation helper for Console.groovy.

- - ### Field Summary

    - ### Fields inherited from class java.io.FilterOutputStream

      `out`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SystemOutputInterceptor(Closure callback)` Constructor
    `SystemOutputInterceptor(Closure callback, boolean output)` Constructor

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `removeConsoleId()` Threads executing a script should call this method after execution completes in order to unregister the consoleId.
    `void` | `setConsoleId(int consoleId)` Threads executing a script should call this method at the start of execution in order to set the id of the console that is hosting the thread of execution.
    `void` | `start()` Starts intercepting System.out/System.err
    `void` | `stop()` Stops intercepting System.out/System.err, sending output to wherever it was going when this interceptor was created.
    `void` | `write(byte[] b, int off, int len)` Intercepts output - more common case of byte[]
    `void` | `write(int b)` Intercepts output - single characters

    - ### Methods inherited from class java.io.FilterOutputStream

      `close, flush, write`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### SystemOutputInterceptor

          public SystemOutputInterceptor(Closure callback)

      Constructor
      Parameters:
        `callback` - accepts the id of the target Console instance and a string to be sent to std out and returns a Boolean. If the return value is true, output will be sent to System.out, otherwise it will not.

    - #### SystemOutputInterceptor

          public SystemOutputInterceptor(Closure callback,
                                         boolean output)

      Constructor
      Parameters:
        `callback` - accepts the id of the target Console instance and a string to be sent to std out and returns a Boolean. If the return value is true, output will be sent to System.out/System.err, otherwise it will not.
        `output` - flag that tells whether System.out needs capturing ot System.err

  - ### Method Detail

    - #### start

          public void start()

      Starts intercepting System.out/System.err

    - #### stop

          public void stop()

      Stops intercepting System.out/System.err, sending output to wherever it was going when this interceptor was created.

    - #### write

          public void write(byte[] b,
                            int off,
                            int len)
                     throws java.io.IOException

      Intercepts output - more common case of byte[]
      Overrides:
        `write` in class `java.io.FilterOutputStream`
      Throws:
        `java.io.IOException`

    - #### write

          public void write(int b)
                     throws java.io.IOException

      Intercepts output - single characters
      Overrides:
        `write` in class `java.io.FilterOutputStream`
      Throws:
        `java.io.IOException`

    - #### setConsoleId

          public void setConsoleId(int consoleId)

      Threads executing a script should call this method at the start of execution in order to set the id of the console that is hosting the thread of execution. This should be called prior to any output that is generated. The consoleId will be passed to the callback.
      Parameters:
        `consoleId` - id of the Console instance executing the script

    - #### removeConsoleId

          public void removeConsoleId()

      Threads executing a script should call this method after execution completes in order to unregister the consoleId.