Package org.apache.commons.io.input

Class QueueInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.io.input.QueueInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class QueueInputStream
extends InputStream

Simple alternative to JDK PipedInputStream; queue input stream provides what's written in queue output stream.

To build an instance, use QueueInputStream.Builder.

Example usage:

 QueueInputStream inputStream = new QueueInputStream();
 QueueOutputStream outputStream = inputStream.newQueueOutputStream();

 outputStream.write("hello world".getBytes(UTF_8));
 inputStream.read();
 

Unlike JDK PipedInputStream and PipedOutputStream, queue input/output streams may be used safely in a single thread or multiple threads. Also, unlike JDK classes, no special meaning is attached to initial or current thread. Instances can be used longer after initial threads exited.

Closing a QueueInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Since:

2.9.0

See Also:

• QueueInputStream.Builder
• QueueOutputStream

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	QueueInputStream.Builder	Builds a new QueueInputStream.

Constructor Summary

Constructors

Constructor	Description
QueueInputStream()	Constructs a new instance with no limit to its internal queue size and zero timeout.
QueueInputStream(BlockingQueue<Integer> blockingQueue)	Deprecated. Use builder(), QueueInputStream.Builder, and QueueInputStream.Builder.get().

Method Summary

Modifier and Type	Method	Description
static QueueInputStream.Builder	builder()	Constructs a new QueueInputStream.Builder.
QueueOutputStream	newQueueOutputStream()	Constructs a new QueueOutputStream instance connected to this.
int	read()	Reads and returns a single byte.
int	read(byte[] b, int offset, int length)	Reads up to length bytes of data from the input stream into an array of bytes.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Details

QueueInputStream

public QueueInputStream()

Constructs a new instance with no limit to its internal queue size and zero timeout.

QueueInputStream

@Deprecated
public QueueInputStream(BlockingQueue<Integer> blockingQueue)

Deprecated.

Use builder(), QueueInputStream.Builder, and QueueInputStream.Builder.get().

Constructs a new instance with given queue and zero timeout.

Parameters:

blockingQueue - backing queue for the stream, null maps to a new blocking queue instance.

Method Details

builder

public static QueueInputStream.Builder builder()

Constructs a new QueueInputStream.Builder.

Returns:

a new QueueInputStream.Builder.

Since:

2.12.0

newQueueOutputStream

public QueueOutputStream newQueueOutputStream()

Constructs a new QueueOutputStream instance connected to this. Writes to the output stream will be visible to this input stream.

Returns:

QueueOutputStream connected to this stream.

read

public int read()

Reads and returns a single byte.

Specified by:

read in class InputStream

Returns:

the byte read, or -1 if a timeout occurs before a queue element is available.

Throws:

IllegalStateException - if thread is interrupted while waiting.

read

public int read(byte[] b,
 int offset,
 int length)

Reads up to length bytes of data from the input stream into an array of bytes. The first byte is read while honoring the timeout; the rest are read while not honoring the timeout. The number of bytes actually read is returned as an integer.

Overrides:

read in class InputStream

Parameters:

b - the buffer into which the data is read.

offset - the start offset in array b at which the data is written.

length - the maximum number of bytes to read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

NullPointerException - If b is null.

IllegalStateException - if thread is interrupted while waiting for the first byte.

IndexOutOfBoundsException - if offset is negative, length is negative, or length is greater than b.length - offset.

Since:

2.20.0