org.apache.commons.io.input

Class BoundedInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.commons.io.input.ProxyInputStream

org.apache.commons.io.input.BoundedInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class BoundedInputStream
extends ProxyInputStream

Reads bytes up to a maximum count and stops once reached.

To build an instance: Use the builder() to access all features.

By default, a BoundedInputStream is unbound; so make sure to call BoundedInputStream.AbstractBuilder.setMaxCount(long).

You can find out how many bytes this stream has seen so far by calling getCount(). This value reflects bytes read and skipped.

Using a ServletInputStream

A ServletInputStream can block if you try to read content that isn't there because it doesn't know whether the content hasn't arrived yet or whether the content has finished. Initialize an BoundedInputStream with the Content-Length sent in the ServletInputStream's header, this stop it from blocking, providing it's been sent with a correct content length in the first place.

Using NIO

 BoundedInputStream s = BoundedInputStream.builder()
   .setPath(Paths.get("MyFile.xml"))
   .setMaxCount(1024)
   .setPropagateClose(false)
   .get();
 
 

Using IO

 BoundedInputStream s = BoundedInputStream.builder()
   .setFile(new File("MyFile.xml"))
   .setMaxCount(1024)
   .setPropagateClose(false)
   .get();
 
 

Counting Bytes

You can set the running count when building, which is most useful when starting from another stream:

 InputStream in = ...;
 BoundedInputStream s = BoundedInputStream.builder()
   .setInputStream(in)
   .setCount(12)
   .setMaxCount(1024)
   .setPropagateClose(false)
   .get();
 
 

Listening for the max count reached

 BoundedInputStream s = BoundedInputStream.builder()
   .setPath(Paths.get("MyFile.xml"))
   .setMaxCount(1024)
   .setOnMaxCount((max, count) -> System.out.printf("Max count %,d reached with a last read count of %,d%n", max, count))
   .get();
 
 

See Also:

BoundedInputStream.Builder

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	BoundedInputStream.AbstractBuilder<T extends BoundedInputStream.AbstractBuilder<T>> For subclassing builders from BoundedInputStream subclassses.
static class	BoundedInputStream.Builder Builds a new BoundedInputStream.

Field Summary

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
BoundedInputStream(BoundedInputStream.Builder builder)
BoundedInputStream(InputStream inputStream, BoundedInputStream.Builder builder)

Method Summary

Modifier and Type	Method and Description
protected void	afterRead(int n) Adds the number of read bytes to the count.
int	available() Invokes the delegate's InputStream.available() method.
static BoundedInputStream.Builder	builder() Constructs a new BoundedInputStream.AbstractBuilder.
void	close() Invokes the delegate's InputStream.close() method if isPropagateClose() is true.
long	getCount() Gets the count of bytes read.
long	getMaxCount() Gets the max count of bytes to read.
long	getRemaining() Gets how many bytes remain to read.
boolean	isPropagateClose() Tests whether the close() method should propagate to the underling InputStream.
void	mark(int readLimit) Invokes the delegate's InputStream.mark(int) method.
boolean	markSupported() Invokes the delegate's InputStream.markSupported() method.
protected void	onMaxLength(long max, long count) A caller has caused a request that would cross the maxLength boundary.
int	read() Invokes the delegate's InputStream.read() method if the current position is less than the limit.
int	read(byte[] b) Invokes the delegate's InputStream.read(byte[]) method.
int	read(byte[] b, int off, int len) Invokes the delegate's InputStream.read(byte[], int, int) method.
void	reset() Invokes the delegate's InputStream.reset() method.
long	skip(long n) Invokes the delegate's InputStream.skip(long) method.
String	toString() Invokes the delegate's Object.toString() method.

Methods inherited from class org.apache.commons.io.input.ProxyInputStream

beforeRead, checkOpen, handleIOException, isClosed, setReference, unwrap

Methods inherited from class java.lang.Object

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

Constructor Detail

BoundedInputStream

BoundedInputStream(BoundedInputStream.Builder builder)
            throws IOException

Throws:

IOException

BoundedInputStream

BoundedInputStream(InputStream inputStream,
                   BoundedInputStream.Builder builder)

Method Detail

afterRead

protected void afterRead(int n)
                  throws IOException

Adds the number of read bytes to the count.

Overrides:

afterRead in class ProxyInputStream

Parameters:

n - number of bytes read, or -1 if no more bytes are available

Throws:

IOException - Not thrown here but subclasses may throw.

available

public int available()
              throws IOException

Invokes the delegate's InputStream.available() method.

Overrides:

available in class ProxyInputStream

Returns:

the number of available bytes, 0 if the stream is closed.

Throws:

IOException - if an I/O error occurs.

builder

public static BoundedInputStream.Builder builder()

Constructs a new BoundedInputStream.AbstractBuilder.

Returns:

a new BoundedInputStream.AbstractBuilder.

close

public void close()
           throws IOException

Invokes the delegate's InputStream.close() method if isPropagateClose() is true.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class ProxyInputStream

Throws:

IOException - if an I/O error occurs.

getCount

public long getCount()

Gets the count of bytes read.

Returns:

The count of bytes read.

getMaxCount

public long getMaxCount()

Gets the max count of bytes to read.

Returns:

The max count of bytes to read.

getRemaining

public long getRemaining()

Gets how many bytes remain to read.

Returns:

bytes how many bytes remain to read.

isPropagateClose

public boolean isPropagateClose()

Tests whether the close() method should propagate to the underling InputStream.

Returns:

true if calling close() propagates to the close() method of the underlying stream or false if it does not.

mark

public void mark(int readLimit)

Invokes the delegate's InputStream.mark(int) method.

Overrides:

mark in class ProxyInputStream

Parameters:

readLimit - read ahead limit

markSupported

public boolean markSupported()

Invokes the delegate's InputStream.markSupported() method.

Overrides:

markSupported in class ProxyInputStream

Returns:

true if mark is supported, otherwise false

See Also:

ProxyInputStream.mark(int), ProxyInputStream.reset()

onMaxLength

protected void onMaxLength(long max,
                           long count)
                    throws IOException

A caller has caused a request that would cross the maxLength boundary.

Delegates to the consumer set in BoundedInputStream.AbstractBuilder.setOnMaxCount(IOBiConsumer).

Parameters:

max - The max count of bytes to read.

count - The count of bytes read.

Throws:

IOException - Subclasses may throw.

read

public int read()
         throws IOException

Invokes the delegate's InputStream.read() method if the current position is less than the limit.

Overrides:

read in class ProxyInputStream

Returns:

the byte read or -1 if the end of stream or the limit has been reached.

Throws:

IOException - if an I/O error occurs.

read

public int read(byte[] b)
         throws IOException

Invokes the delegate's InputStream.read(byte[]) method.

Overrides:

read in class ProxyInputStream

Parameters:

b - the buffer to read the bytes into

Returns:

the number of bytes read or -1 if the end of stream or the limit has been reached.

Throws:

IOException - if an I/O error occurs.

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException

Invokes the delegate's InputStream.read(byte[], int, int) method.

Overrides:

read in class ProxyInputStream

Parameters:

b - the buffer to read the bytes into

off - The start offset

len - The number of bytes to read

Returns:

the number of bytes read or -1 if the end of stream or the limit has been reached.

Throws:

IOException - if an I/O error occurs.

reset

public void reset()
           throws IOException

Invokes the delegate's InputStream.reset() method.

Overrides:

reset in class ProxyInputStream

Throws:

IOException - if an I/O error occurs.

skip

public long skip(long n)
          throws IOException

Invokes the delegate's InputStream.skip(long) method.

Overrides:

skip in class ProxyInputStream

Parameters:

n - the number of bytes to skip

Returns:

the actual number of bytes skipped

Throws:

IOException - if an I/O error occurs.

toString

public String toString()

Invokes the delegate's Object.toString() method.

Overrides:

toString in class Object

Returns:

the delegate's Object.toString()