Package org.apache.commons.io.input

Class ProxyInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

org.apache.commons.io.input.ProxyInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

AutoCloseInputStream, BOMInputStream, BoundedInputStream, CloseShieldInputStream, CountingInputStream, MarkShieldInputStream, ObservableInputStream, SwappedDataInputStream, TaggedInputStream, TeeInputStream

public abstract class ProxyInputStream
extends FilterInputStream

A proxy stream which acts as a FilterInputStream, by passing all method calls on to the proxied stream, not changing which methods are called.

It is an alternative base class to FilterInputStream to increase reusability, because FilterInputStream changes the methods being called, such as read(byte[]) to read(byte[], int, int).

In addition, this class allows you to:

• notify a subclass that n bytes are about to be read through beforeRead(int)
• notify a subclass that n bytes were read through afterRead(int)
• notify a subclass that an exception was caught through handleIOException(IOException)
• unwrap() itself

Constructor Summary

Constructors

Constructor	Description
ProxyInputStream(InputStream proxy)	Constructs a new ProxyInputStream.

Method Summary

Modifier and Type	Method	Description
int	available()	Invokes the delegate's InputStream.available() method.
void	close()	Invokes the delegate's InputStream.close() method.
void	mark(int readLimit)	Invokes the delegate's InputStream.mark(int) method.
boolean	markSupported()	Invokes the delegate's InputStream.markSupported() method.
int	read()	Invokes the delegate's InputStream.read() method unless the stream is closed.
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.
ProxyInputStream	setReference(InputStream in)	Sets the underlying input stream.
long	skip(long n)	Invokes the delegate's InputStream.skip(long) method.
InputStream	unwrap()	Unwraps this instance by returning the underlying InputStream.

Methods inherited from class java.io.InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Methods inherited from class java.lang.Object

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

Constructor Details

ProxyInputStream

public ProxyInputStream(InputStream proxy)

Constructs a new ProxyInputStream.

Parameters:

proxy - the InputStream to proxy.

Method Details

available

public int available()
              throws IOException

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

Overrides:

available in class FilterInputStream

Returns:

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

Throws:

IOException - if an I/O error occurs.

close

public void close()
           throws IOException

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

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException - if an I/O error occurs.

mark

public void mark(int readLimit)

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

Overrides:

mark in class FilterInputStream

Parameters:

readLimit - read ahead limit.

markSupported

public boolean markSupported()

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

Overrides:

markSupported in class FilterInputStream

Returns:

true if this stream instance supports the mark and reset methods; false otherwise.

See Also:

• mark(int)
• reset()

read

public int read()
         throws IOException

Invokes the delegate's InputStream.read() method unless the stream is closed.

Overrides:

read in class FilterInputStream

Returns:

the byte read or EOF if we reached the end of stream.

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 FilterInputStream

Parameters:

b - the buffer to read the bytes into.

Returns:

the number of bytes read or EOF if we reached the end of stream.

Throws:

IOException -

• If the first byte cannot be read for any reason other than the end of the file,
• if the input stream has been closed, or
• if some other 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 FilterInputStream

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 EOF if we reached the end of stream.

Throws:

IOException -

• If the first byte cannot be read for any reason other than the end of the file,
• if the input stream has been closed, or
• if some other I/O error occurs.

reset

public void reset()
           throws IOException

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

Overrides:

reset in class FilterInputStream

Throws:

IOException - if this stream has not been marked or if the mark has been invalidated.

setReference

public ProxyInputStream setReference(InputStream in)

Sets the underlying input stream.

Parameters:

in - The input stream to set in FilterInputStream.in.

Returns:

this instance.

Since:

2.19.0

skip

public long skip(long n)
          throws IOException

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

Overrides:

skip in class FilterInputStream

Parameters:

n - the number of bytes to skip.

Returns:

the actual number of bytes skipped.

Throws:

IOException - if the stream does not support seek, or if some other I/O error occurs.

unwrap

public InputStream unwrap()

Unwraps this instance by returning the underlying InputStream.

Use with caution; useful to query the underlying InputStream.

Returns:

the underlying InputStream.

Since:

2.16.0