Class ThresholdingOutputStream
- java.lang.Object
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- java.io.OutputStream
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- org.apache.tomcat.util.http.fileupload.ThresholdingOutputStream
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- All Implemented Interfaces:
java.io.Closeable,java.io.Flushable,java.lang.AutoCloseable
- Direct Known Subclasses:
DeferredFileOutputStream
public abstract class ThresholdingOutputStream extends java.io.OutputStreamAn output stream which triggers an event when a specified number of bytes of data have been written to it. The event can be used, for example, to throw an exception if a maximum has been reached, or to switch the underlying stream type when the threshold is exceeded.This class overrides all
OutputStreammethods. However, these overrides ultimately call the corresponding methods in the underlying output stream implementation.NOTE: This implementation may trigger the event before the threshold is actually reached, since it triggers when a pending write operation would cause the threshold to be exceeded.
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Constructor Summary
Constructors Constructor Description ThresholdingOutputStream(int threshold)Constructs an instance of this class which will trigger an event at the specified threshold.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected voidcheckThreshold(int count)Checks to see if writing the specified number of bytes would cause the configured threshold to be exceeded.voidclose()Closes this output stream and releases any system resources associated with this stream.voidflush()Flushes this output stream and forces any buffered output bytes to be written out.protected abstract java.io.OutputStreamgetStream()Returns the underlying output stream, to which the correspondingOutputStreammethods in this class will ultimately delegate.booleanisThresholdExceeded()Determines whether or not the configured threshold has been exceeded for this output stream.protected abstract voidthresholdReached()Indicates that the configured threshold has been reached, and that a subclass should take whatever action necessary on this event.voidwrite(byte[] b)Writesb.lengthbytes from the specified byte array to this output stream.voidwrite(byte[] b, int off, int len)Writeslenbytes from the specified byte array starting at offsetoffto this output stream.voidwrite(int b)Writes the specified byte to this output stream.
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Method Detail
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write
public void write(int b) throws java.io.IOExceptionWrites the specified byte to this output stream.- Specified by:
writein classjava.io.OutputStream- Parameters:
b- The byte to be written.- Throws:
java.io.IOException- if an error occurs.
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write
public void write(byte[] b) throws java.io.IOExceptionWritesb.lengthbytes from the specified byte array to this output stream.- Overrides:
writein classjava.io.OutputStream- Parameters:
b- The array of bytes to be written.- Throws:
java.io.IOException- if an error occurs.
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write
public void write(byte[] b, int off, int len) throws java.io.IOExceptionWriteslenbytes from the specified byte array starting at offsetoffto this output stream.- Overrides:
writein classjava.io.OutputStream- Parameters:
b- The byte array from which the data will be written.off- The start offset in the byte array.len- The number of bytes to write.- Throws:
java.io.IOException- if an error occurs.
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flush
public void flush() throws java.io.IOExceptionFlushes this output stream and forces any buffered output bytes to be written out.- Specified by:
flushin interfacejava.io.Flushable- Overrides:
flushin classjava.io.OutputStream- Throws:
java.io.IOException- if an error occurs.
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close
public void close() throws java.io.IOExceptionCloses this output stream and releases any system resources associated with this stream.- Specified by:
closein interfacejava.lang.AutoCloseable- Specified by:
closein interfacejava.io.Closeable- Overrides:
closein classjava.io.OutputStream- Throws:
java.io.IOException- if an error occurs.
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isThresholdExceeded
public boolean isThresholdExceeded()
Determines whether or not the configured threshold has been exceeded for this output stream.- Returns:
trueif the threshold has been reached;falseotherwise.
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checkThreshold
protected void checkThreshold(int count) throws java.io.IOExceptionChecks to see if writing the specified number of bytes would cause the configured threshold to be exceeded. If so, triggers an event to allow a concrete implementation to take action on this.- Parameters:
count- The number of bytes about to be written to the underlying output stream.- Throws:
java.io.IOException- if an error occurs.
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getStream
protected abstract java.io.OutputStream getStream() throws java.io.IOExceptionReturns the underlying output stream, to which the correspondingOutputStreammethods in this class will ultimately delegate.- Returns:
- The underlying output stream.
- Throws:
java.io.IOException- if an error occurs.
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thresholdReached
protected abstract void thresholdReached() throws java.io.IOExceptionIndicates that the configured threshold has been reached, and that a subclass should take whatever action necessary on this event. This may include changing the underlying output stream.- Throws:
java.io.IOException- if an error occurs.
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