NullInputStream (Apache Commons IO 2.5 API)

java.lang.Object
- java.io.InputStream
- - org.apache.commons.io.input.NullInputStream

All Implemented Interfaces:

Closeable, AutoCloseable
```
public class NullInputStream
extends InputStream
```
A functional, light weight InputStream that emulates a stream of a specified size.
This implementation provides a light weight object for testing with an InputStream where the contents don't matter.
One use case would be for testing the handling of large InputStream as it can emulate that scenario without the overhead of actually processing large numbers of bytes - significantly speeding up test execution times.
This implementation returns zero from the method that reads a byte and leaves the array unchanged in the read methods that are passed a byte array. If alternative data is required the processByte() and processBytes() methods can be implemented to generate data, for example:
```
  public class TestInputStream extends NullInputStream {
      public TestInputStream(int size) {
          super(size);
      }
      protected int processByte() {
          return ... // return required value here
      }
      protected void processBytes(byte[] bytes, int offset, int length) {
          for (int i = offset; i < length; i++) {
              bytes[i] = ... // set array value here
          }
      }
  }
 
```
Since:

1.3

Version:

$Id: NullInputStream.java 1586350 2014-04-10 15:57:20Z ggregory $

Constructor Summary

Constructors
Constructor and Description
`NullInputStream(long size)` Create an `InputStream` that emulates a specified size which supports marking and does not throw EOFException.
`NullInputStream(long size, boolean markSupported, boolean throwEofException)` Create an `InputStream` that emulates a specified size with option settings.

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`available()` Return the number of bytes that can be read.
`void`	`close()` Close this input stream - resets the internal state to the initial values.
`long`	`getPosition()` Return the current position.
`long`	`getSize()` Return the size this `InputStream` emulates.
`void`	`mark(int readlimit)` Mark the current position.
`boolean`	`markSupported()` Indicates whether mark is supported.
`protected int`	`processByte()` Return a byte value for the `read()` method.
`protected void`	`processBytes(byte[] bytes, int offset, int length)` Process the bytes for the `read(byte[], offset, length)` method.
`int`	`read()` Read a byte.
`int`	`read(byte[] bytes)` Read some bytes into the specified array.
`int`	`read(byte[] bytes, int offset, int length)` Read the specified number bytes into an array.
`void`	`reset()` Reset the stream to the point when mark was last called.
`long`	`skip(long numberOfBytes)` Skip a specified number of bytes.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - NullInputStream
```
public NullInputStream(long size)
```
    Create an InputStream that emulates a specified size which supports marking and does not throw EOFException.
    
    Parameters:
    size - The size of the input stream to emulate.
  - NullInputStream
```
public NullInputStream(long size,
               boolean markSupported,
               boolean throwEofException)
```
    Create an InputStream that emulates a specified size with option settings.
    
    Parameters:
    size - The size of the input stream to emulate.
    markSupported - Whether this instance will support the mark() functionality.
    throwEofException - Whether this implementation will throw an EOFException or return -1 when the end of file is reached.
- Method Detail
  - getPosition
```
public long getPosition()
```
    Return the current position.
    
    Returns:
    the current position.
  - getSize
```
public long getSize()
```
    Return the size this InputStream emulates.
    
    Returns:
    The size of the input stream to emulate.
  - available
```
public int available()
```
    Return the number of bytes that can be read.
    
    Overrides:
    
    available in class InputStream
    
    Returns:
    The number of bytes that can be read.
  - close
```
public void close()
           throws IOException
```
    Close this input stream - resets the internal state to the initial values.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Overrides:
    
    close in class InputStream
    
    Throws:
    
    IOException - If an error occurs.
  - mark
```
public void mark(int readlimit)
```
    Mark the current position.
    
    Overrides:
    
    mark in class InputStream
    
    Parameters:
    readlimit - The number of bytes before this marked position is invalid.
    
    Throws:
    
    UnsupportedOperationException - if mark is not supported.
  - markSupported
```
public boolean markSupported()
```
    Indicates whether mark is supported.
    
    Overrides:
    
    markSupported in class InputStream
    
    Returns:
    Whether mark is supported or not.
  - read
```
public int read()
         throws IOException
```
    Read a byte.
    
    Specified by:
    
    read in class InputStream
    
    Returns:
    Either The byte value returned by processByte() or -1 if the end of file has been reached and throwEofException is set to false.
    
    Throws:
    
    EOFException - if the end of file is reached and throwEofException is set to true.
    
    IOException - if trying to read past the end of file.
  - read
```
public int read(byte[] bytes)
         throws IOException
```
    Read some bytes into the specified array.
    
    Overrides:
    
    read in class InputStream
    
    Parameters:
    bytes - The byte array to read into
    
    Returns:
    The number of bytes read or -1 if the end of file has been reached and throwEofException is set to false.
    
    Throws:
    
    EOFException - if the end of file is reached and throwEofException is set to true.
    
    IOException - if trying to read past the end of file.
  - read
```
public int read(byte[] bytes,
       int offset,
       int length)
         throws IOException
```
    Read the specified number bytes into an array.
    
    Overrides:
    
    read in class InputStream
    
    Parameters:
    bytes - The byte array to read into.
    offset - The offset to start reading bytes into.
    length - The number of bytes to read.
    
    Returns:
    The number of bytes read or -1 if the end of file has been reached and throwEofException is set to false.
    
    Throws:
    
    EOFException - if the end of file is reached and throwEofException is set to true.
    
    IOException - if trying to read past the end of file.
  - reset
```
public void reset()
           throws IOException
```
    Reset the stream to the point when mark was last called.
    
    Overrides:
    
    reset in class InputStream
    
    Throws:
    
    UnsupportedOperationException - if mark is not supported.
    
    IOException - If no position has been marked or the read limit has been exceed since the last position was marked.
  - skip
```
public long skip(long numberOfBytes)
          throws IOException
```
    Skip a specified number of bytes.
    
    Overrides:
    
    skip in class InputStream
    
    Parameters:
    numberOfBytes - The number of bytes to skip.
    
    Returns:
    The number of bytes skipped or -1 if the end of file has been reached and throwEofException is set to false.
    
    Throws:
    
    EOFException - if the end of file is reached and throwEofException is set to true.
    
    IOException - if trying to read past the end of file.
  - processByte
```
protected int processByte()
```
    Return a byte value for the read() method.
    This implementation returns zero.
    
    Returns:
    This implementation always returns zero.
  - processBytes
```
protected void processBytes(byte[] bytes,
                int offset,
                int length)
```
    Process the bytes for the read(byte[], offset, length) method.
    This implementation leaves the byte array unchanged.
    
    Parameters:
    bytes - The byte array
    offset - The offset to start at.
    length - The number of bytes.

Class NullInputStream

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

NullInputStream

NullInputStream

Method Detail

getPosition

getSize

available

close

mark

markSupported

read

read

read

reset

skip

processByte

processBytes