Interface CharStreamSource
- All Known Subinterfaces:
OutputSegment
- All Known Implementing Classes:
OutputDocument
,Renderer
,SourceCompactor
,SourceFormatter
,TextExtractor
For small amounts of data, or when memory usage isn't a prime concern (e.g. in client-side applications), the simplest way to obtain the data is by calling
the toString()
method.
If the character stream might contain a large amount of data it is recommended to use the writeTo(Writer)
method to access the data,
especially if running in a multi-user server environment.
The advantage of providing textual data via this interface is that it gives the user the choice as to whether they would like to receive the data as a stream of characters, or all as a single string. Furthermore, it allows the "active" stream source (see below) to be easily converted into a "passive" stream source if required.
An active stream source is a stream source that actively outputs to a passive receiver ("sink").
The writeTo(Writer)
method in this interface signifies an active source as the transmission of the entire data stream takes place when this method is executed.
In this case the sink is the object that supplies the Writer
object, and would typically contain a getWriter()
method.
The sink is passive because it just supplies a Writer
object to be written to by the code in some other class.
A passive stream source is a stream source that is read from by an active sink.
For character streams, a passive stream source simply supplies a Reader
object.
The active sink would typically contain a readFrom(Reader)
method which actively reads the entire data stream from the Reader
object.
The CharStreamSourceUtil.getReader(CharStreamSource)
method converts a CharStreamSource
into a Reader
,
allowing the data from the active CharStreamSource
to be consumed by an active sink with a readFrom(Reader)
method.
Every implementing class must override the toString()
method to return the output as a string.
An easy way to implement this is by calling the CharStreamSourceUtil.toString(this)
method,
which buffers the output from the writeTo(Writer)
method into a string.
- See Also:
-
Method Summary
Modifier and TypeMethodDescriptionvoid
appendTo
(Appendable appendable) Appends the output to the specifiedAppendable
object.long
Returns the estimated maximum number of characters in the output, or-1
if no estimate is available.toString()
Returns the output as a string.void
Writes the output to the specifiedWriter
.
-
Method Details
-
writeTo
Writes the output to the specifiedWriter
.- Parameters:
writer
- the destinationjava.io.Writer
for the output.- Throws:
IOException
- if an I/O exception occurs.
-
appendTo
Appends the output to the specifiedAppendable
object.- Parameters:
appendable
- the destinationjava.lang.Appendable
object for the output.- Throws:
IOException
- if an I/O exception occurs.
-
getEstimatedMaximumOutputLength
long getEstimatedMaximumOutputLength()Returns the estimated maximum number of characters in the output, or-1
if no estimate is available.The returned value should be used as a guide for efficiency purposes only, for example to set an initial
StringBuilder
capacity. There is no guarantee that the length of the output is indeed less than this value, as classes implementing this method often use assumptions based on typical usage to calculate the estimate.Although implementations of this method should never return a value less than -1, users of this method must not assume that this will always be the case. Standard practice is to interpret any negative value as meaning that no estimate is available.
- Returns:
- the estimated maximum number of characters in the output, or
-1
if no estimate is available.
-
toString
String toString()Returns the output as a string.
-