Module org.apache.wicket.util
Package org.apache.wicket.util.io

Class ProxyInputStream

java.lang.Object
java.io.InputStream
java.io.FilterInputStream
org.apache.wicket.util.io.ProxyInputStream
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
BOMInputStream
public abstract class ProxyInputStream extends FilterInputStream
A Proxy stream which acts as expected, that is it passes the method calls on to the proxied stream and doesn't change which methods are being 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).

See the protected methods for ways in which a subclass can easily decorate a stream with custom pre-, post- or error processing functionality.

Version:
$Id$

  • Constructor Details

    • ProxyInputStream

      public ProxyInputStream(InputStream proxy)
      Constructs a new ProxyInputStream.
      Parameters:
      proxy - the InputStream to delegate to

  • Method Details

    • read

      public int read() throws IOException
      Invokes the delegate's read() method.
      Overrides:
      read in class FilterInputStream
      Returns:
      the byte read or -1 if the end of stream
      Throws:
      IOException - if an I/O error occurs

    • read

      public int read(byte[] bts) throws IOException
      Invokes the delegate's read(byte[]) method.
      Overrides:
      read in class FilterInputStream
      Parameters:
      bts - the buffer to read the bytes into
      Returns:
      the number of bytes read or -1 if the end of stream
      Throws:
      IOException - if an I/O error occurs

    • read

      public int read(byte[] bts, int off, int len) throws IOException
      Invokes the delegate's read(byte[], int, int) method.
      Overrides:
      read in class FilterInputStream
      Parameters:
      bts - 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
      Throws:
      IOException - if an I/O error occurs

    • skip

      public long skip(long ln) throws IOException
      Invokes the delegate's skip(long) method.
      Overrides:
      skip in class FilterInputStream
      Parameters:
      ln - the number of bytes to skip
      Returns:
      the actual number of bytes skipped
      Throws:
      IOException - if an I/O error occurs

    • available

      public int available() throws IOException
      Invokes the delegate's available() method.
      Overrides:
      available in class FilterInputStream
      Returns:
      the number of available bytes
      Throws:
      IOException - if an I/O error occurs

    • close

      public void close() throws IOException
      Invokes the delegate's 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 mark(int) method.
      Overrides:
      mark in class FilterInputStream
      Parameters:
      readlimit - read ahead limit

    • reset

      public void reset() throws IOException
      Invokes the delegate's reset() method.
      Overrides:
      reset in class FilterInputStream
      Throws:
      IOException - if an I/O error occurs

    • markSupported

      public boolean markSupported()
      Invokes the delegate's markSupported() method.
      Overrides:
      markSupported in class FilterInputStream
      Returns:
      true if mark is supported, otherwise false

    • beforeRead

      protected void beforeRead(int n) throws IOException
      Invoked by the read methods before the call is proxied. The number of bytes that the caller wanted to read (1 for the read() method, buffer length for read(byte[]), etc.) is given as an argument.

      Subclasses can override this method to add common pre-processing functionality without having to override all the read methods. The default implementation does nothing.

      Note this method is not called from skip(long) or reset(). You need to explicitly override those methods if you want to add pre-processing steps also to them.

      Parameters:
      n - number of bytes that the caller asked to be read
      Throws:
      IOException - if the pre-processing fails
      Since:
      2.0

    • afterRead

      protected void afterRead(int n) throws IOException
      Invoked by the read methods after the proxied call has returned successfully. The number of bytes returned to the caller (or -1 if the end of stream was reached) is given as an argument.

      Subclasses can override this method to add common post-processing functionality without having to override all the read methods. The default implementation does nothing.

      Note this method is not called from skip(long) or reset(). You need to explicitly override those methods if you want to add post-processing steps also to them.

      Parameters:
      n - number of bytes read, or -1 if the end of stream was reached
      Throws:
      IOException - if the post-processing fails
      Since:
      2.0

    • handleIOException

      protected void handleIOException(IOException e) throws IOException
      Handle any IOExceptions thrown.

      This method provides a point to implement custom exception handling. The default behaviour is to re-throw the exception.

      Parameters:
      e - The IOException thrown
      Throws:
      IOException - if an I/O error occurs
      Since:
      2.0