Class ProxyInputStream
- All Implemented Interfaces:
Closeable,AutoCloseable
- Direct Known Subclasses:
AutoCloseInputStream,BOMInputStream,BoundedInputStream,CloseShieldInputStream,CountingInputStream,MarkShieldInputStream,ObservableInputStream,SwappedDataInputStream,TaggedInputStream,TeeInputStream
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
This class does not add any state (no additional instance variables).
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Field Summary
Fields inherited from class java.io.FilterInputStream
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprotected voidafterRead(int n) Invoked by thereadmethods after the proxied call has returned successfully.intInvokes the delegate'savailable()method.protected voidbeforeRead(int n) Invoked by thereadmethods before the call is proxied.voidclose()Invokes the delegate'sclose()method.protected voidHandles any IOExceptions thrown; by default, throws the given exception.voidmark(int readLimit) Invokes the delegate'smark(int)method.booleanInvokes the delegate'smarkSupported()method.intread()Invokes the delegate'sread()method.intread(byte[] b) Invokes the delegate'sread(byte[])method.intread(byte[] b, int off, int len) Invokes the delegate'sread(byte[], int, int)method.voidreset()Invokes the delegate'sreset()method.longskip(long n) Invokes the delegate'sskip(long)method.unwrap()Unwraps this instance by returning the underlying InputStream.
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Constructor Details
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ProxyInputStream
Constructs a new ProxyInputStream.- Parameters:
proxy- the InputStream to delegate to
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Method Details
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afterRead
Invoked by thereadmethods 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)orreset(). 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
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available
Invokes the delegate'savailable()method.- Overrides:
availablein classFilterInputStream- Returns:
- the number of available bytes
- Throws:
IOException- if an I/O error occurs.
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beforeRead
Invoked by thereadmethods before the call is proxied. The number of bytes that the caller wanted to read (1 for theread()method, buffer length forread(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)orreset(). 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
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close
Invokes the delegate'sclose()method.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classFilterInputStream- Throws:
IOException- if an I/O error occurs.
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handleIOException
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
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mark
Invokes the delegate'smark(int)method.- Overrides:
markin classFilterInputStream- Parameters:
readLimit- read ahead limit
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markSupported
Invokes the delegate'smarkSupported()method.- Overrides:
markSupportedin classFilterInputStream- Returns:
- true if mark is supported, otherwise false
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read
Invokes the delegate'sread()method.- Overrides:
readin classFilterInputStream- Returns:
- the byte read or -1 if the end of stream
- Throws:
IOException- if an I/O error occurs.
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read
Invokes the delegate'sread(byte[])method.- Overrides:
readin classFilterInputStream- 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.
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read
Invokes the delegate'sread(byte[], int, int)method.- Overrides:
readin classFilterInputStream- Parameters:
b- the buffer to read the bytes intooff- The start offsetlen- 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.
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reset
Invokes the delegate'sreset()method.- Overrides:
resetin classFilterInputStream- Throws:
IOException- if an I/O error occurs.
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skip
Invokes the delegate'sskip(long)method.- Overrides:
skipin classFilterInputStream- Parameters:
n- the number of bytes to skip- Returns:
- the actual number of bytes skipped
- Throws:
IOException- if an I/O error occurs.
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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
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