Module org.postgresql.pljava.internal

Package org.postgresql.pljava.internal

Class MarkableSequenceReader

java.lang.Object

java.io.Reader

org.postgresql.pljava.internal.MarkableSequenceReader

All Implemented Interfaces:

Closeable, AutoCloseable, Readable

public class MarkableSequenceReader
extends Reader

Like a MarkableSequenceInputStream but for characters.

This class implements mark and reset by calling the corresponding methods on the underlying readers; it does not add buffering or have any means of providing mark and reset support if the underlying readers do not.

As with SequenceInputStream, each underlying reader, when completely read and no longer needed, is closed to free resources. This instance itself will remain in "open at EOF" condition until explicitly closed, but does not prevent reclamation of the underlying readers.

Unlike SequenceInputStream, this class can keep underlying readers open, after fully reading them, if a mark has been set, so that reset will be possible. When a mark is no longer needed, it can be canceled (by calling mark with a readlimit of 0) to again allow the underlying readers to be reclaimed as soon as possible.

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor	Description
MarkableSequenceReader(Reader... streams)	Create a MarkableSequenceReader from one or more existing readers.

Method Summary

Modifier and Type	Method	Description
void	close()
void	mark(int readlimit)	Marks the current position in this reader.
boolean	markSupported()	Tests if this reader supports the mark and reset methods.
int	read()
int	read(char[] b, int off, int len)
void	reset()
long	skip(long n)

Methods inherited from class java.io.Reader

nullReader, read, read, ready, transferTo

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MarkableSequenceReader

public MarkableSequenceReader(Reader... streams)

Create a MarkableSequenceReader from one or more existing readers.

Parameters:

streams - Sequence of Readers that will be read from in order.

Throws:

NullPointerException - if streams is null, or contains null for any stream.

Method Details

read

public int read()
         throws IOException

Overrides:

read in class Reader

Throws:

IOException

read

public int read(char[] b,
 int off,
 int len)
         throws IOException

Specified by:

read in class Reader

Throws:

IOException

skip

public long skip(long n)
          throws IOException

Overrides:

skip in class Reader

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class Reader

Throws:

IOException

mark

public void mark(int readlimit)
          throws IOException

Marks the current position in this reader. In this implementation, it is possible to 'cancel' a mark, by passing this method a readlimit of zero, returning the reader immediately to the state of having no mark.

Overrides:

mark in class Reader

Throws:

IOException

reset

public void reset()
           throws IOException

Overrides:

reset in class Reader

Throws:

IOException

markSupported

public boolean markSupported()

Tests if this reader supports the mark and reset methods.

For any instance of this class, the result is determined by the first call to this method, and does not change thereafter. At the first call, the result is determined only by the underlying readers remaining to be read (or, if a mark has been set, which is possible before checking this method, then by the underlying readers including and following the one that was current when the mark was set). The result will be true unless any of those underlying readers reports it as false.

Overrides:

markSupported in class Reader