Package org.apache.commons.io.output
Class ThresholdingOutputStream
java.lang.Object
java.io.OutputStream
org.apache.commons.io.output.ThresholdingOutputStream
- All Implemented Interfaces:
Closeable,Flushable,AutoCloseable
- Direct Known Subclasses:
DeferredFileOutputStream
An output stream which triggers an event on the first write that causes
the total number of bytes written to the stream to exceed a configured threshold,
and every subsequent write. The event
can be used, for example, to throw an exception if a maximum has been reached,
or to switch the underlying stream when the threshold is exceeded.
This class overrides all OutputStream methods. 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.
See also the subclass DeferredFileOutputStream.
- See Also:
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Constructor Summary
ConstructorsConstructorDescriptionThresholdingOutputStream(int threshold) Constructs an instance of this class which will trigger an event at the specified threshold.ThresholdingOutputStream(int threshold, IOConsumer<ThresholdingOutputStream> thresholdConsumer, IOFunction<ThresholdingOutputStream, OutputStream> outputStreamGetter) Constructs an instance of this class which will trigger an event at the specified threshold. -
Method Summary
Modifier and TypeMethodDescriptionprotected 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.longGets the number of bytes that have been written to this output stream.protected OutputStreamGets the underlying output stream, to which the correspondingOutputStreammethods in this class will ultimately delegate.protected OutputStreamDeprecated.intGets the threshold, in bytes, at which an event will be triggered.booleanTests whether or not the configured threshold has been exceeded for this output stream.protected voidResets the byteCount to zero.protected voidsetByteCount(long count) Sets the byteCount to count.protected voidIndicates 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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Constructor Details
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ThresholdingOutputStream
Constructs an instance of this class which will trigger an event at the specified threshold.- Parameters:
threshold- The number of bytes at which to trigger an event.
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ThresholdingOutputStream
public ThresholdingOutputStream(int threshold, IOConsumer<ThresholdingOutputStream> thresholdConsumer, IOFunction<ThresholdingOutputStream, OutputStream> outputStreamGetter) Constructs an instance of this class which will trigger an event at the specified threshold. A negative threshold has no meaning and will be treated as 0- Parameters:
threshold- The number of bytes at which to trigger an event.thresholdConsumer- Accepts reaching the threshold.outputStreamGetter- Gets the output stream.- Since:
- 2.9.0
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Method Details
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checkThreshold
Checks 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:
IOException- if an error occurs.
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close
Closes this output stream and releases any system resources associated with this stream.- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classOutputStream- Throws:
IOException- if an error occurs.
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flush
Flushes this output stream and forces any buffered output bytes to be written out.- Specified by:
flushin interfaceFlushable- Overrides:
flushin classOutputStream- Throws:
IOException- if an error occurs.
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getByteCount
Gets the number of bytes that have been written to this output stream.- Returns:
- The number of bytes written.
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getOutputStream
Gets the underlying output stream, to which the correspondingOutputStreammethods in this class will ultimately delegate.- Returns:
- The underlying output stream.
- Throws:
IOException- if an error occurs.- Since:
- 2.14.0
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getStream
Deprecated.UsegetOutputStream().Gets the underlying output stream, to which the correspondingOutputStreammethods in this class will ultimately delegate.- Returns:
- The underlying output stream.
- Throws:
IOException- if an error occurs.
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getThreshold
Gets the threshold, in bytes, at which an event will be triggered.- Returns:
- The threshold point, in bytes.
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isThresholdExceeded
Tests 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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resetByteCount
Resets the byteCount to zero. You can call this fromthresholdReached()if you want the event to be triggered again. -
setByteCount
Sets the byteCount to count. Useful for re-opening an output stream that has previously been written to.- Parameters:
count- The number of bytes that have already been written to the output stream- Since:
- 2.5
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thresholdReached
Indicates 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:
IOException- if an error occurs.
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write
Writesb.lengthbytes from the specified byte array to this output stream.- Overrides:
writein classOutputStream- Parameters:
b- The array of bytes to be written.- Throws:
IOException- if an error occurs.
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write
Writeslenbytes from the specified byte array starting at offsetoffto this output stream.- Overrides:
writein classOutputStream- 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:
IOException- if an error occurs.
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write
Writes the specified byte to this output stream.- Specified by:
writein classOutputStream- Parameters:
b- The byte to be written.- Throws:
IOException- if an error occurs.
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getOutputStream().