Class CompressionFilter
- java.lang.Object
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- org.apache.mina.core.filterchain.IoFilterAdapter
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- org.apache.mina.filter.util.WriteRequestFilter
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- org.apache.mina.filter.compression.CompressionFilter
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- All Implemented Interfaces:
IoFilter
public class CompressionFilter extends WriteRequestFilter
AnIoFilter
which compresses all data using JZlib. Support for the LZW (DLCZ) algorithm is also planned.This filter only supports compression using the PARTIAL FLUSH method, since that is the only method useful when doing stream level compression.
This filter supports compression/decompression of the input and output channels selectively. It can also be enabled/disabled on the fly.
This filter does not discard the zlib objects, keeping them around for the entire life of the filter. This is because the zlib dictionary needs to be built up over time, which is used during compression and decompression. Over time, as repetitive data is sent over the wire, the compression efficiency steadily increases.
Note that the zlib header is written only once. It is not necessary that the data received after processing by this filter may not be complete due to packet fragmentation.
It goes without saying that the other end of this stream should also have a compatible compressor/decompressor using the same algorithm.
- Author:
- Apache MINA Project
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Nested Class Summary
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Nested classes/interfaces inherited from interface org.apache.mina.core.filterchain.IoFilter
IoFilter.NextFilter
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Field Summary
Fields Modifier and Type Field Description static int
COMPRESSION_DEFAULT
The default compression level used.static int
COMPRESSION_MAX
Max compression level.static int
COMPRESSION_MIN
Provides the best speed at the price of a low compression ratio.static int
COMPRESSION_NONE
No compression done on the data.static AttributeKey
DISABLE_COMPRESSION_ONCE
A flag that allows you to disable compression once.
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Constructor Summary
Constructors Constructor Description CompressionFilter()
Creates a new instance which compresses outboud data and decompresses inbound data with default compression level.CompressionFilter(boolean compressInbound, boolean compressOutbound, int compressionLevel)
Creates a new instance.CompressionFilter(int compressionLevel)
Creates a new instance which compresses outboud data and decompresses inbound data with the specified compressionLevel.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected Object
doFilterWrite(IoFilter.NextFilter nextFilter, IoSession session, WriteRequest writeRequest)
boolean
isCompressInbound()
boolean
isCompressOutbound()
void
messageReceived(IoFilter.NextFilter nextFilter, IoSession session, Object message)
FiltersIoHandler.messageReceived(IoSession,Object)
event.void
onPostRemove(IoFilterChain parent, String name, IoFilter.NextFilter nextFilter)
Invoked after this filter is removed from the specified parent.void
onPreAdd(IoFilterChain parent, String name, IoFilter.NextFilter nextFilter)
Invoked before this filter is added to the specified parent.void
setCompressInbound(boolean compressInbound)
Sets if incoming data has to be compressed.void
setCompressOutbound(boolean compressOutbound)
Set if outgoing data has to be compressed.-
Methods inherited from class org.apache.mina.filter.util.WriteRequestFilter
filterWrite, messageSent
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Methods inherited from class org.apache.mina.core.filterchain.IoFilterAdapter
destroy, exceptionCaught, filterClose, init, inputClosed, onPostAdd, onPreRemove, sessionClosed, sessionCreated, sessionIdle, sessionOpened, toString
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Field Detail
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COMPRESSION_MAX
public static final int COMPRESSION_MAX
Max compression level. Will give the highest compression ratio, but will also take more cpu time and is the slowest.- See Also:
- Constant Field Values
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COMPRESSION_MIN
public static final int COMPRESSION_MIN
Provides the best speed at the price of a low compression ratio.- See Also:
- Constant Field Values
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COMPRESSION_NONE
public static final int COMPRESSION_NONE
No compression done on the data.- See Also:
- Constant Field Values
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COMPRESSION_DEFAULT
public static final int COMPRESSION_DEFAULT
The default compression level used. Provides the best balance between speed and compression- See Also:
- Constant Field Values
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DISABLE_COMPRESSION_ONCE
public static final AttributeKey DISABLE_COMPRESSION_ONCE
A flag that allows you to disable compression once.
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Constructor Detail
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CompressionFilter
public CompressionFilter()
Creates a new instance which compresses outboud data and decompresses inbound data with default compression level.
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CompressionFilter
public CompressionFilter(int compressionLevel)
Creates a new instance which compresses outboud data and decompresses inbound data with the specified compressionLevel.- Parameters:
compressionLevel
- the level of compression to be used. Must be one ofCOMPRESSION_DEFAULT
,COMPRESSION_MAX
,COMPRESSION_MIN
, andCOMPRESSION_NONE
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CompressionFilter
public CompressionFilter(boolean compressInbound, boolean compressOutbound, int compressionLevel)
Creates a new instance.- Parameters:
compressInbound
- true if data read is to be decompressedcompressOutbound
- true if data written is to be compressedcompressionLevel
- the level of compression to be used. Must be one ofCOMPRESSION_DEFAULT
,COMPRESSION_MAX
,COMPRESSION_MIN
, andCOMPRESSION_NONE
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Method Detail
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messageReceived
public void messageReceived(IoFilter.NextFilter nextFilter, IoSession session, Object message) throws Exception
Description copied from class:IoFilterAdapter
FiltersIoHandler.messageReceived(IoSession,Object)
event.- Specified by:
messageReceived
in interfaceIoFilter
- Overrides:
messageReceived
in classIoFilterAdapter
- Parameters:
nextFilter
- theIoFilter.NextFilter
for this filter. You can reuse this object until this filter is removed from the chain.session
- TheIoSession
which has received this eventmessage
- The received message- Throws:
Exception
- If an error occurred while processing the event
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doFilterWrite
protected Object doFilterWrite(IoFilter.NextFilter nextFilter, IoSession session, WriteRequest writeRequest) throws IOException
- Specified by:
doFilterWrite
in classWriteRequestFilter
- Throws:
IOException
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onPreAdd
public void onPreAdd(IoFilterChain parent, String name, IoFilter.NextFilter nextFilter) throws Exception
Description copied from class:IoFilterAdapter
Invoked before this filter is added to the specified parent. Please note that this method can be invoked more than once if this filter is added to more than one parents. This method is not invoked beforeIoFilter.init()
is invoked.- Specified by:
onPreAdd
in interfaceIoFilter
- Overrides:
onPreAdd
in classIoFilterAdapter
- Parameters:
parent
- the parent who called this methodname
- the name assigned to this filternextFilter
- theIoFilter.NextFilter
for this filter. You can reuse this object until this filter is removed from the chain.- Throws:
Exception
- If an error occurred while processing the event
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isCompressInbound
public boolean isCompressInbound()
- Returns:
- true if incoming data is being compressed.
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setCompressInbound
public void setCompressInbound(boolean compressInbound)
Sets if incoming data has to be compressed.- Parameters:
compressInbound
- true if the incoming data has to be compressed
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isCompressOutbound
public boolean isCompressOutbound()
- Returns:
- true if the filter is compressing data being written.
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setCompressOutbound
public void setCompressOutbound(boolean compressOutbound)
Set if outgoing data has to be compressed.- Parameters:
compressOutbound
- true if the outgoing data has to be compressed
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onPostRemove
public void onPostRemove(IoFilterChain parent, String name, IoFilter.NextFilter nextFilter) throws Exception
Description copied from class:IoFilterAdapter
Invoked after this filter is removed from the specified parent. Please note that this method can be invoked more than once if this filter is removed from more than one parents. This method is always invoked beforeIoFilter.destroy()
is invoked.- Specified by:
onPostRemove
in interfaceIoFilter
- Overrides:
onPostRemove
in classIoFilterAdapter
- Parameters:
parent
- the parent who called this methodname
- the name assigned to this filternextFilter
- theIoFilter.NextFilter
for this filter. You can reuse this object until this filter is removed from the chain.- Throws:
Exception
- If an error occurred while processing the event
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