com.ibm.as400.access

Class ConvTableReader

java.lang.Object

java.io.Reader

java.io.InputStreamReader

com.ibm.as400.access.ConvTableReader

All Implemented Interfaces:

java.io.Closeable, java.lang.Readable

public class ConvTableReader
extends java.io.InputStreamReader

Represents a Toolbox converter that uses stateful character conversion. That is, it wraps an underlying InputStream and reads/caches the appropriate number of bytes to return the requested number of Unicode characters. This is especially useful for mixed-byte tables where the number of converted Unicode characters is almost never the same as the number of underlying EBCDIC bytes. This class exists primarily for use with the IFSTextFile... classes, but other components are free to use it as well.

See Also:

ConvTableWriter, ReaderInputStream

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

Constructors

Constructor and Description
ConvTableReader(java.io.InputStream in) Creates a ConvTableReader that uses the default character encoding.
ConvTableReader(java.io.InputStream in, int ccsid) Creates a ConvTableReader that uses the specified CCSID.
ConvTableReader(java.io.InputStream in, int ccsid, BidiConversionProperties properties) Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.
ConvTableReader(java.io.InputStream in, int ccsid, boolean isXML) Creates a ConvTableReader that uses the specified CCSID.
ConvTableReader(java.io.InputStream in, int ccsid, int bidiStringType) Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.
ConvTableReader(java.io.InputStream in, int ccsid, int bidiStringType, boolean isXML) Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.
ConvTableReader(java.io.InputStream in, int ccsid, int bidiStringType, int cacheSize) Creates a ConvTableReader that uses the specified CCSID, bi-directional string type, and internal cache size.
ConvTableReader(java.io.InputStream in, java.lang.String encoding) Creates a ConvTableReader that uses the specified character encoding.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Closes this ConvTableReader and its underlying input stream.
int	getByteCacheSize() Returns the maximum number of bytes that may be stored in the internal buffer.
int	getCacheSize() Returns the maximum number of characters that may be stored in the internal buffer.
int	getCcsid() Returns the CCSID used by this ConvTableReader.
java.lang.String	getEncoding() Returns the encoding used by this ConvTableReader.
boolean	markSupported() ConvTableReader does not support the mark() operation.
int	read() Reads a single character.
int	read(char[] buffer) Reads characters into the specified array.
int	read(char[] buffer, int offset, int length) Reads characters into a portion of the specified array.
java.lang.String	read(int length) Reads up to length characters out of the underlying stream.
boolean	ready() Tells whether this ConvTableReader is ready to be read.
long	skip(long length) Skips the specified number of characters in the underlying stream.

Methods inherited from class java.io.Reader

mark, read, reset

Methods inherited from class java.lang.Object

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

Constructor Detail

ConvTableReader

public ConvTableReader(java.io.InputStream in)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the default character encoding. The CCSID this reader uses may be set if a known mapping exists for this platform's default character encoding.

Parameters:

in - The InputStream from which to read characters.

Throws:

java.io.UnsupportedEncodingException - If the default character encoding or its associated CCSID is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               java.lang.String encoding)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified character encoding. The CCSID this reader uses may be set if a known mapping exists for the given encoding.

Parameters:

in - The InputStream from which to read characters.

encoding - The name of a supported character encoding.

Throws:

java.io.UnsupportedEncodingException - If the specified character encoding or its associated CCSID is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid,
               boolean isXML)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

isXML - flag that stream is from an XML column type (needed to strip xml declaration)

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid,
               int bidiStringType)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

bidiStringType - The bi-directional string type.

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid,
               int bidiStringType,
               boolean isXML)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

bidiStringType - The bi-directional string type.

isXML - flag that stream is from an XML column type (needed to strip xml declaration)

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid,
               BidiConversionProperties properties)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID and bi-directional string type.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

properties - The bidi conversion properties.

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

ConvTableReader

public ConvTableReader(java.io.InputStream in,
               int ccsid,
               int bidiStringType,
               int cacheSize)
                throws java.io.UnsupportedEncodingException

Creates a ConvTableReader that uses the specified CCSID, bi-directional string type, and internal cache size.

Parameters:

in - The InputStream from which to read characters.

ccsid - The CCSID.

bidiStringType - The bi-directional string type.

cacheSize - The number of characters to store in the internal buffer. The default is 1024. This number must be greater than zero.

Throws:

java.io.UnsupportedEncodingException - If the specified CCSID or its corresponding character encoding is not supported.

Method Detail

close

public void close()
           throws java.io.IOException

Closes this ConvTableReader and its underlying input stream. Calling close() multiple times will not throw an exception.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.InputStreamReader

Throws:

java.io.IOException - If an I/O exception occurs.

getByteCacheSize

public int getByteCacheSize()

Returns the maximum number of bytes that may be stored in the internal buffer. This number represents the number of bytes that may be read from the underlying InputStream any time a read() method is called on this ConvTableReader.

Returns:

The size of the byte cache in use by this ConvTableReader.

getCacheSize

public int getCacheSize()

Returns the maximum number of characters that may be stored in the internal buffer. This number represents the number of characters that may be converted from the underlying InputStream any time a read() method is called on this ConvTableReader. Note that this is not the number of bytes actually read from the InputStream. The maximum number of bytes that can be read is determined by getByteCacheSize().

Returns:

The size of the character cache in use by this ConvTableReader.

getCcsid

public int getCcsid()

Returns the CCSID used by this ConvTableReader.

Returns:

The CCSID, or -1 if the CCSID is not known.

getEncoding

public java.lang.String getEncoding()

Returns the encoding used by this ConvTableReader. If the CCSID is not known, the superclass encoding is returned. Otherwise, the corresponding encoding for the CCSID is returned, which may be null if no such mapping exists.

Overrides:

getEncoding in class java.io.InputStreamReader

Returns:

The encoding, or null if the encoding is not known.

markSupported

public boolean markSupported()

ConvTableReader does not support the mark() operation.

Overrides:

markSupported in class java.io.Reader

Returns:

false.

read

public int read()
         throws java.io.IOException

Reads a single character. If close() is called prior to calling this method, an exception will be thrown.

Overrides:

read in class java.io.InputStreamReader

Returns:

The character read, or -1 if the end of the stream has been reached.

Throws:

java.io.IOException - If an I/O exception occurs.

read

public int read(char[] buffer)
         throws java.io.IOException

Reads characters into the specified array. If close() is called prior to calling this method, an exception will be thrown.

Overrides:

read in class java.io.Reader

Parameters:

buffer - The destination buffer.

Returns:

The number of characters read, or -1 if the end of the stream has been reached.

Throws:

java.io.IOException - If an I/O exception occurs.

read

public int read(char[] buffer,
       int offset,
       int length)
         throws java.io.IOException

Reads characters into a portion of the specified array. If close() is called prior to calling this method, an exception will be thrown.

Overrides:

read in class java.io.InputStreamReader

Parameters:

buffer - The destination buffer.

offset - The offset into the buffer at which to begin storing data.

length - The maximum number of characters to store. If a zero length is specified, this method does nothing and returns 0.

Returns:

The number of characters read, or -1 if the end of the stream has been reached.

Throws:

java.io.IOException - If an I/O exception occurs.

read

public java.lang.String read(int length)
                      throws java.io.IOException

Reads up to length characters out of the underlying stream. If close() is called prior to calling this method, an exception will be thrown.

Parameters:

length - The maximum number of Unicode characters to return as a String. Note that the number of bytes read from the underlying InputStream could be greater than length. If a zero length is specified, this method does nothing and returns "".

Returns:

A String of up to length Unicode characters, or null if the end of the stream has been reached. The actual number of characters returned may be less than the specified length if the end of the underlying InputStream is reached while reading.

Throws:

java.io.IOException - If an I/O exception occurs.

ready

public boolean ready()
              throws java.io.IOException

Tells whether this ConvTableReader is ready to be read. A ConvTableReader is ready if its input buffer is not empty or if bytes are available to be read from the underlying input stream. If close() is called, a call to ready() will always return false.

Overrides:

ready in class java.io.InputStreamReader

Returns:

true if the ConvTableReader is ready to read characters; false otherwise.

Throws:

java.io.IOException - If an I/O exception occurs.

skip

public long skip(long length)
          throws java.io.IOException

Skips the specified number of characters in the underlying stream. If close() is called prior to calling this method, an exception will be thrown.

Overrides:

skip in class java.io.Reader

Parameters:

length - The number of characters to skip.

Returns:

The number of characters actually skipped.

Throws:

java.io.IOException - If an I/O exception occurs.