de.susebox.jtopas

Class ReaderSource

java.lang.Object

de.susebox.jtopas.ReaderSource

All Implemented Interfaces:

TokenizerSource

public class ReaderSource
extends java.lang.Object
implements TokenizerSource

This implementation of the TokenizerSource interface uses the JDK Reader class to realize the requested functionality. Note that the backing Reader can be changed during the parse operations of the Tokenizer instance that accesses this ReaderSource.

Author:

Heiko Blau

See Also:

de.susebox.java.util.Tokenizer, de.susebox.java.util.AbstractTokenizer, Reader

Constructor Summary

Constructors

Constructor and Description
ReaderSource() The default constructor constructs a ReaderSource instance that reads from nowhere.
ReaderSource(java.io.File file) This Constructor takes an File to create a Reader from.
ReaderSource(java.io.InputStream is) This Constructor takes an InputStream.
ReaderSource(java.io.Reader reader) Constructing an ReaderSource object with the given Reader instance to get input data from.
ReaderSource(java.lang.String path) This Constructor takes an String as a file path to create a Reader from.

Method Summary

Modifier and Type	Method and Description
void	close() This method can be called to close streams (either Reader or InputStream passed to the constructors or implicitely created when this ReaderSource is setup.
java.io.Reader	getReader() Retrieving the current Reader.
int	read(char[] cbuf, int offset, int maxChars) The method calls the Reader.read(char[], int, int) method of the currently backing Reader.
void	setReader(java.io.Reader reader) Setting the backing Reader instance.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReaderSource

public ReaderSource()

The default constructor constructs a ReaderSource instance that reads from nowhere. A call to the read(char[], int, int) method will immediately return the end-of-file condition.

See Also:

read(char[], int, int)

ReaderSource

public ReaderSource(java.io.Reader reader)

Constructing an ReaderSource object with the given Reader instance to get input data from. null is a valid value. The read(char[], int, int) method will return an end-of-file condition in that case.
The given Reader instance can be closed manually or by calling the close() method of this ReaderSource object.

Parameters:

reader - the backing Reader or null

ReaderSource

public ReaderSource(java.io.InputStream is)

This Constructor takes an InputStream. It is comfortable when You dont have a Reader in the first place. However, when using this constructor, the method close() should be called after tokenizing has been finished. It will also close the given InputStream.
The method accepts null leading to an end-of-file condition in the first call to read(char[], int, int).

Parameters:

is - the input stream or null

ReaderSource

public ReaderSource(java.io.File file)
             throws java.io.IOException

This Constructor takes an File to create a Reader from. When using this constructor, the method close() should be called after tokenizing has been finished.
The method accepts null leading to an end-of-file condition in the first call to read(char[], int, int).

Parameters:

file - the File object that should be read or null

Throws:

java.io.IOException

ReaderSource

public ReaderSource(java.lang.String path)
             throws java.io.IOException

This Constructor takes an String as a file path to create a Reader from. When using this constructor, the method close() should be called after tokenizing has been finished.
The method accepts null leading to an end-of-file condition in the first call to read(char[], int, int).

Parameters:

path - a file path or null

Throws:

java.io.IOException

Method Detail

read

public int read(char[] cbuf,
                int offset,
                int maxChars)
         throws java.lang.Exception

The method calls the Reader.read(char[], int, int) method of the currently backing Reader. If no Reader is set so far, -1 (end-of-file) is returned.

Specified by:

read in interface TokenizerSource

Parameters:

cbuf - buffer to receive data

offset - position from where the data should be inserted in cbuf

maxChars - maximum number of characters to be read into cbuf

Returns:

actually read characters or -1 on an end-of-file condition

Throws:

java.lang.Exception - anything that could happen during read, most likely IOException

close

public void close()

This method can be called to close streams (either Reader or InputStream passed to the constructors or implicitely created when this ReaderSource is setup.
It is a shortcut for otherwise nessecary operations that will usually consist of calling Reader.close() and InputStream.close() probably combined with an exception handling to catch IOException.

setReader

public void setReader(java.io.Reader reader)

Setting the backing Reader instance. null is a valid value. The read(char[], int, int) method will return no data (end-of-file) in that case.

Parameters:

reader - the backing Reader

See Also:

read(char[], int, int), getReader()

getReader

public java.io.Reader getReader()

Retrieving the current Reader. The method may return null if a setReader(java.io.Reader) with null has occured before.

Returns:

the current Reader or null

See Also:

setReader(java.io.Reader)