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:

This class does not add any state (no additional instance variables).

  • Field Summary

    Fields inherited from class java.io.FilterInputStream

    in

  • Constructor Summary

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

  • Method Summary

    Modifier and Type
    Method
    Description
    protected void
    afterRead(int n)
    Invoked by the read methods after the proxied call has returned successfully.
    int
    available()
    Invokes the delegate's available() method.
    protected void
    beforeRead(int n)
    Invoked by the read methods before the call is proxied.
    void
    close()
    Invokes the delegate's close() method.
    protected void
    handleIOException(IOException e)
    Handles any IOExceptions thrown; by default, throws the given exception.
    void
    mark(int readLimit)
    Invokes the delegate's mark(int) method.
    boolean
    markSupported()
    Invokes the delegate's markSupported() method.
    int
    read()
    Invokes the delegate's read() method.
    int
    read(byte[] b)
    Invokes the delegate's read(byte[]) method.
    int
    read(byte[] b, int off, int len)
    Invokes the delegate's read(byte[], int, int) method.
    void
    reset()
    Invokes the delegate's reset() method.
    long
    skip(long n)
    Invokes the delegate's skip(long) method.
    InputStream
    unwrap()
    Unwraps this instance by returning the underlying InputStream.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • ProxyInputStream

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

  • Method Details

    • 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 in a subclass.
      Since:
      2.0

    • 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.

    • 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 in a subclass.
      Since:
      2.0

    • 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.

    • handleIOException

      protected void handleIOException(IOException e) throws IOException
      Handles any IOExceptions thrown; by default, throws the given exception.

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

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

    • mark

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

    • markSupported

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

    • 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[] b) throws IOException
      Invokes the delegate's 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 the end of stream
      Throws:
      IOException - if an I/O error occurs.

    • read

      public int read(byte[] b, int off, int len) throws IOException
      Invokes the delegate's 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 -1 if the end of stream
      Throws:
      IOException - if an I/O error occurs.

    • 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.

    • skip

      public long skip(long n) throws IOException
      Invokes the delegate's 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 an 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