public class StreamCharBuffer extends groovy.lang.GroovyObjectSupport implements groovy.lang.Writable, java.lang.CharSequence, Encodeable, EncodedAppenderWriterFactory, java.io.Externalizable, StreamEncodeable, StreamingEncoderWritable, java.lang.Cloneable
StreamCharBuffer is a multipurpose in-memory buffer that can replace JDK in-memory buffers (StringBuffer, StringBuilder, StringWriter).
Grails GSP rendering uses this class as a buffer that is optimized for performance.
StreamCharBuffer keeps the buffer in a linked list of "chunks". The main difference compared to JDK in-memory buffers (StringBuffer, StringBuilder & StringWriter) is that the buffer can be held in several smaller buffers ("chunks" here). In JDK in-memory buffers, the buffer has to be expanded whenever it gets filled up. The old buffer's data is copied to the new one and the old one is discarded. In StreamCharBuffer, there are several ways to prevent unnecessary allocation & copy operations. The StreamCharBuffer contains a linked list of different type of chunks: char arrays, java.lang.String chunks and other StreamCharBuffers as sub chunks. A StringChunk is appended to the linked list whenever a java.lang.String of a length that exceeds the "stringChunkMinSize" value is written to the buffer.
Grails tag libraries also use a StreamCharBuffer to "capture" the output of
the taglib and return it to the caller. The buffer can be appended to it's
parent buffer directly without extra object generation (like converting to
java.lang.String in between).
for example this line of code in a taglib would just append the buffer
returned from the body closure evaluation to the buffer of the taglib:
out << body()
other example:
out << g.render(template: '/some/template', model:[somebean: somebean])
There's no extra java.lang.String generation overhead.
There's a java.io.Writer interface for appending character data to the buffer and a java.io.Reader interface for reading data.
Each getReader() call will create a new reader instance that keeps
it own state.
There is a alternative method getReader(boolean) for creating the
reader. When reader is created by calling getReader(true), the reader will
remove already read characters from the buffer. In this mode only a single
reader instance is supported.
There's also several other options for reading data:
readAsCharArray() reads the buffer to a char[] array
readAsString() reads the buffer and wraps the char[] data as a
String
writeTo(Writer) writes the buffer to a java.io.Writer
toCharArray() returns the buffer as a char[] array, caches the
return value internally so that this method can be called several times.
toString() returns the buffer as a String, caches the return value
internally
By using the "connectTo" method, one can connect the buffer directly to a target java.io.Writer. The internal buffer gets flushed automaticly to the target whenever the buffer gets filled up. See connectTo(Writer).
This class is not thread-safe. Object instances of this class are intended to be used by a single Thread. The Reader and Writer interfaces can be open simultaneous and the same Thread can write and read several times.
Main operation principle:
StreamCharBuffer keeps the buffer in a linked link of "chunks".
The main difference compared to JDK in-memory buffers (StringBuffer,
StringBuilder & StringWriter) is that the buffer can be held in several
smaller buffers ("chunks" here).
In JDK in-memory buffers, the buffer has to be expanded whenever it gets
filled up. The old buffer's data is copied to the new one and the old one is
discarded.
In StreamCharBuffer, there are several ways to prevent unnecessary allocation
& copy operations.
There can be several different type of chunks: char arrays (
CharBufferChunk), String chunks (StringChunk) and other
StreamCharBuffers as sub chunks (StreamCharBufferSubChunk).
Child StreamCharBuffers can be changed after adding to parent buffer. The flush() method must be called on the child buffer's Writer to notify the parent that the child buffer's content has been changed (used for calculating total size).
A StringChunk is appended to the linked list whenever a java.lang.String of a length that exceeds the "stringChunkMinSize" value is written to the buffer.
If the buffer is in "connectTo" mode, any String or char[] that's length is over writeDirectlyToConnectedMinSize gets written directly to the target. The buffer content will get fully flushed to the target before writing the String or char[].
There can be several targets "listening" the buffer in "connectTo" mode. The same content will be written to all targets.
Growable chunksize: By default, a newly allocated chunk's size will grow
based on the total size of all written chunks.
The default growProcent value is 100. If the total size is currently 1024,
the newly created chunk will have a internal buffer that's size is 1024.
Growable chunksize can be turned off by setting the growProcent to 0.
There's a default maximum chunksize of 1MB by default. The minimum size is
the initial chunksize size.
System properties to change default configuration parameters:
| System Property name | Description | Default value |
|---|---|---|
| streamcharbuffer.chunksize | default chunk size - the size the first allocated buffer | 512 |
| streamcharbuffer.maxchunksize | maximum chunk size - the maximum size of the allocated buffer | 1048576 |
| streamcharbuffer.growprocent | growing buffer percentage - the newly allocated buffer is defined by total_size * (growpercent/100) | 100 |
| streamcharbuffer.subbufferchunkminsize | minimum size of child StreamCharBuffer chunk - if the size is smaller, the content is copied to the parent buffer | 512 |
| streamcharbuffer.substringchunkminsize | minimum size of String chunks - if the size is smaller, the content is copied to the buffer | 512 |
| streamcharbuffer.chunkminsize | minimum size of chunk that gets written directly to the target in connected mode. | 256 |
| Modifiers | Name | Description |
|---|---|---|
static class |
StreamCharBuffer.EncodedPart |
|
static interface |
StreamCharBuffer.LazyInitializingMultipleWriter |
|
static interface |
StreamCharBuffer.LazyInitializingWriter |
Interface for a Writer that gets initialized if it is used Can be used for passing in to "connectTo" method of StreamCharBuffer |
class |
StreamCharBuffer.StreamCharBufferReader |
|
class |
StreamCharBuffer.StreamCharBufferWriter |
This is the java.io.Writer implementation for StreamCharBuffer |
| Constructor and description |
|---|
StreamCharBuffer
() |
StreamCharBuffer
(int chunkSize) |
StreamCharBuffer
(int chunkSize, int growProcent) |
StreamCharBuffer
(int chunkSize, int growProcent, int maxChunkSize) |
| Type Params | Return Type | Name and description |
|---|---|---|
|
public void |
appendStreamCharBufferChunk(StreamCharBuffer subBuffer) |
|
public void |
appendStreamCharBufferChunk(StreamCharBuffer subBuffer, java.util.List<Encoder> encoders) |
|
protected static final void |
arrayCopy(char[] src, int srcPos, char[] dest, int destPos, int length) |
|
public boolean |
asBoolean() |
|
public java.lang.Object |
asType(java.lang.Class clazz) |
|
protected boolean |
bufferChanged(StreamCharBuffer buffer) |
|
public char |
charAt(int index) |
|
public final void |
clear()Clears the buffer and notifies the parents of this buffer of the change. |
|
public StreamCharBuffer |
clone() |
|
public final void |
connectTo(java.io.Writer w)Connect this buffer to a target Writer. |
|
public final void |
connectTo(java.io.Writer w, boolean autoFlush) |
|
public final void |
connectTo(LazyInitializingWriter w) |
|
public final void |
connectTo(LazyInitializingWriter w, boolean autoFlush) |
|
public LazyInitializingWriter |
createEncodingInitializer(EncoderAware encoderLookup, EncodingStateRegistryLookup encodingStateRegistryLookup, LazyInitializingWriter writers) |
|
public java.util.List<EncodedPart> |
dumpEncodedParts() |
|
protected void |
emptyAfterReading() |
|
public java.lang.CharSequence |
encode(Encoder encoder) |
|
public final void |
encodeInStreamingModeTo(EncoderAware encoderLookup, EncodingStateRegistryLookup encodingStateRegistryLookup, boolean autoFlush, java.io.Writer w) |
|
public final void |
encodeInStreamingModeTo(EncoderAware encoderLookup, EncodingStateRegistryLookup encodingStateRegistryLookup, boolean autoFlush, LazyInitializingWriter writers) |
|
public void |
encodeTo(EncodedAppender appender, Encoder encoder) |
|
public void |
encodeTo(java.io.Writer writer, EncodesToWriter encoder) |
|
public StreamCharBuffer |
encodeToBuffer(Encoder encoder) |
|
public StreamCharBuffer |
encodeToBuffer(Encoder encoder, boolean allowSubBuffers, boolean notifyParentBuffersEnabled) |
|
public StreamCharBuffer |
encodeToBuffer(java.util.List<Encoder> encoders) |
|
public StreamCharBuffer |
encodeToBuffer(java.util.List<Encoder> encoders, boolean allowSubBuffers, boolean notifyParentBuffersEnabled) |
|
public boolean |
equals(java.lang.Object o)equals uses String.equals to check for equality to support compatibility with String instances in maps, sets, etc. |
|
public int |
getBufferChangesCounter() |
|
public int |
getChunkMinSize() |
|
protected java.util.List<StreamCharBuffer> |
getCurrentParentBuffers() |
|
public java.io.Reader |
getReader()Creates a new Reader instance for reading/consuming data from the buffer. |
|
public java.io.Reader |
getReader(boolean removeAfterReading)Like getReader(), but when removeAfterReading is true, the read data will be removed from the buffer. |
|
public int |
getSubBufferChunkMinSize() |
|
public int |
getSubStringChunkMinSize() |
|
public int |
getWriteDirectlyToConnectedMinSize() |
|
public java.io.Writer |
getWriter() |
|
public java.io.Writer |
getWriter() |
|
public java.io.Writer |
getWriter()Writer interface for adding/writing data to the buffer. |
|
public java.io.Writer |
getWriterForEncoder() |
|
public java.io.Writer |
getWriterForEncoder(Encoder encoder) |
|
public java.io.Writer |
getWriterForEncoder(Encoder encoder, EncodingStateRegistry encodingStateRegistry) |
|
public java.io.Writer |
getWriterForEncoder(Encoder encoder, EncodingStateRegistry encodingStateRegistry, boolean ignoreEncodingState) |
|
public int |
hashCode(){@inheritDoc} |
|
public LazyInitializingWriter[] |
initializeMultiple(StreamCharBuffer buffer, boolean autoFlushMode) |
|
public boolean |
isAllowSubBuffers() |
|
protected boolean |
isChunkSizeResizeable() |
|
public boolean |
isConnectedMode() |
|
public boolean |
isEmpty() |
|
public boolean |
isNotifyParentBuffersEnabled() |
|
public boolean |
isPreferSubChunkWhenWritingToOtherBuffer() |
|
public int |
length() |
|
protected EncodingStateRegistry |
lookupDefaultEncodingStateRegistry() |
|
protected int |
markBufferChanged() |
|
public void |
markEncoded(StringChunk strChunk) |
|
public java.lang.Object |
methodMissing(java.lang.String name, java.lang.Object args)Delegates methodMissing to String object |
|
protected void |
notifyBufferChange() |
|
protected void |
notifyPreferSubChunkEnabled() |
|
public java.lang.String |
plus(java.lang.String value) |
|
public java.lang.String |
plus(java.lang.Object value) |
|
public void |
readExternal(java.io.ObjectInput in) |
|
public StringChunk |
readToSingleStringChunk(boolean registerEncodingState) |
|
public final void |
removeConnections() |
|
public final void |
reset() |
|
public final void |
reset(boolean resetChunkSize)resets the state of this buffer (empties it) |
|
protected void |
resizeChunkSizeAsProcentageOfTotalSize() |
|
public void |
setAllowSubBuffers(boolean allowSubBuffers) |
|
public void |
setChunkMinSize(int size) |
|
public void |
setNotifyParentBuffersEnabled(boolean notifyParentBuffersEnabled)By default the parent buffers (a buffer where this buffer has been appended to) get notified of changed to this buffer. |
|
public void |
setPreferSubChunkWhenWritingToOtherBuffer(boolean prefer) |
|
public void |
setSubBufferChunkMinSize(int size) |
|
public void |
setSubStringChunkMinSize(int size)Minimum size for a String to be added as a StringChunk instead of copying content to the char[] buffer of the current StreamCharBufferChunk |
|
public void |
setWriteDirectlyToConnectedMinSize(int size)Minimum size for a String or char[] to get written directly to connected writer (in "connectTo" mode). |
|
public int |
size() |
|
public java.lang.CharSequence |
subSequence(int start, int end) |
|
public char[] |
toCharArray()Reads the buffer to a char[]. |
|
public java.lang.String |
toString(){@inheritDoc} |
|
public void |
writeExternal(java.io.ObjectOutput out) |
|
public java.io.Writer |
writeTo(java.io.Writer target)Writes the buffer content to a target java.io.Writer |
|
public void |
writeTo(java.io.Writer target, boolean flushTarget, boolean emptyAfter)Writes the buffer content to a target java.io.Writer |
| Methods inherited from class | Name |
|---|---|
class groovy.lang.GroovyObjectSupport |
groovy.lang.GroovyObjectSupport#getMetaClass(), groovy.lang.GroovyObjectSupport#setMetaClass(groovy.lang.MetaClass), groovy.lang.GroovyObjectSupport#wait(long, int), groovy.lang.GroovyObjectSupport#wait(long), groovy.lang.GroovyObjectSupport#wait(), groovy.lang.GroovyObjectSupport#equals(java.lang.Object), groovy.lang.GroovyObjectSupport#toString(), groovy.lang.GroovyObjectSupport#hashCode(), groovy.lang.GroovyObjectSupport#getClass(), groovy.lang.GroovyObjectSupport#notify(), groovy.lang.GroovyObjectSupport#notifyAll(), groovy.lang.GroovyObjectSupport#invokeMethod(java.lang.String, java.lang.Object), groovy.lang.GroovyObjectSupport#setProperty(java.lang.String, java.lang.Object), groovy.lang.GroovyObjectSupport#getProperty(java.lang.String) |
Clears the buffer and notifies the parents of this buffer of the change.
Connect this buffer to a target Writer. When the buffer (a chunk) get filled up, it will automaticly write it's content to the Writer
equals uses String.equals to check for equality to support compatibility with String instances in maps, sets, etc.
Creates a new Reader instance for reading/consuming data from the buffer. Each call creates a new instance that will keep it's reading state. There can be several readers on the buffer. (single thread only supported)
Like getReader(), but when removeAfterReading is true, the read data will be removed from the buffer.
Writer interface for adding/writing data to the buffer.
{@inheritDoc} Uses String's hashCode to support compatibility with String instances in maps, sets, etc.
Delegates methodMissing to String object
name - The name of the methodargs - The argumentsresets the state of this buffer (empties it)
By default the parent buffers (a buffer where this buffer has been appended to) get notified of changed to this buffer. You can control the notification behavior with this property. Setting this property to false will also clear the references to parent buffers if there are any.
Minimum size for a String to be added as a StringChunk instead of copying content to the char[] buffer of the current StreamCharBufferChunk
Minimum size for a String or char[] to get written directly to connected writer (in "connectTo" mode).
Reads the buffer to a char[]. Caches the result if there aren't any readers.
{@inheritDoc} Reads (and empties) the buffer to a String, but caches the return value for subsequent calls. If more content has been added between 2 calls, the returned value will be joined from the previously cached value and the data read from the buffer.
Writes the buffer content to a target java.io.Writer
Writes the buffer content to a target java.io.Writer
target - WriterflushTarget - calls target.flush() before finishingemptyAfter - empties the buffer if true