ca.idms.io
Class NativeObject

java.lang.Object
  ca.idms.io.TraceObject
      ca.idms.io.NativeObject

All Implemented Interfaces:

Native, Trace

Direct Known Subclasses:

NativeBase, NativeBuffer

public class NativeObject
extends TraceObject
implements Native

Provides a default implementation of the Native interface. This class reads and writes an array of unconverted bytes, and is used when conversion is not needed. Derived classes can override the readNative(ca.idms.io.NativeDataInputStream) and writeNative(ca.idms.io.NativeDataOutputStream) methods to convert data using the methods provided by the NativeDataInputStream and NativeDataOutputStream classes.

Author:

Dave Ross

See Also:

Native, NativeFormat, TraceObject

Field Summary

protected byte[]	buffer Buffer for data in native format.
protected int	length Length of data in byte array.
protected int	offset Start offset of data in byte array.

Fields inherited from class ca.idms.io.TraceObject

exclude, EXCLUDE, FALSE, include, INCLUDE, logWriter, PREFIX, PROPERTIES_FILE, PROPERTIES_KEY, snap, SNAP, SNAP_BYTES, SNAP_NATIVE, SNAP_OBJECT, SNAP_SQL, snapBytes, snapNative, snapObject, snapSql, stub, trace, TRACE, TRACE_FILE, TRACE_LIFE, TRACE_NATIVE, TRACE_PRODUCT, traceLife, traceNative, traceStream, TRUE

Constructor Summary

protected	NativeObject() Creates an uninitialized NativeObject.
	NativeObject(byte[] buf) Creates a NativeObject from a byte array.
	NativeObject(byte[] buf, int off, int len) Creates an initialized NativeObject.
	NativeObject(int len) Creates an initialized NativeObject.

Method Summary

protected java.lang.Object	get(java.lang.reflect.Field f) Overrides the default get method to allow the default snap method access to the value of a non-public variable.
byte[]	getBuffer() Gets the byte array buffer.
short	getClient() The default getClient method returns 0.
int	getOffset() Gets the byte array offset.
int	length() Computes the size of the native form of the object.
int	length(NativeFormat fmt) Computes the size of the native form the object.
boolean	readBuffer(NativeDataInputStream in) Conditionally reads the buffer from a stream.
void	readNative(NativeDataInputStream in) Reads the object from a stream in native format.
void	snap() Overrides snap in TraceObject and displays the byte array.
boolean	writeBuffer(NativeDataOutputStream out) Conditionally writes the buffer to a stream.
void	writeNative(NativeDataOutputStream out) Writes the object to a stream in native format.

Methods inherited from class ca.idms.io.TraceObject

finalize, getBoolean, getClasses, getInteger, getProperty, listProperties, message, parseList, print, print, print, println, println, snap, snap, snap, snap, snap, snap, toHex, toHex, toHex, toHex, toHex, toString, trace, trace, trace, trace, trace, trace, traceEntry, unloadProperties

Methods inherited from class java.lang.Object

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

Field Detail

buffer

protected byte[] buffer

Buffer for data in native format.

offset

protected int offset

Start offset of data in byte array.

length

protected int length

Length of data in byte array.

Constructor Detail

NativeObject

protected NativeObject()

Creates an uninitialized NativeObject. This is meant to be used as a base class for Native objects that perform data conversion on input and output. The methods in this class can then be used to read and write the object to a stream of bytes with no conversion.

NativeObject

public NativeObject(int len)

Creates an initialized NativeObject. An empty byte array is allocated.

Parameters:

len - length of byte array.

NativeObject

public NativeObject(byte[] buf)

Creates a NativeObject from a byte array.

Parameters:

buf - an existing byte array.

NativeObject

public NativeObject(byte[] buf,
                    int off,
                    int len)

Creates an initialized NativeObject.

The byte array is referenced, not copied. The buffer can be null, which allows a derived class to defer setting the buffer. In this case the derived class is responsible for ensuring the validity of the offset and length.

Parameters:

buf - existing buffer.

off - index of start of data.

len - length of data.

Method Detail

get

protected java.lang.Object get(java.lang.reflect.Field f)
                        throws java.lang.IllegalAccessException

Overrides the default get method to allow the default snap method access to the value of a non-public variable.

Overrides:

get in class TraceObject

Parameters:

f - a Field returned by Class.getDeclaredFields

Returns:

the Object named by f

Throws:

java.lang.IllegalAccessException - should not really happen, but Field.get requires it

See Also:

TraceObject.snap, TraceObject.snap()

snap

public void snap()

Overrides snap in TraceObject and displays the byte array.

Specified by:

snap in interface Trace

Overrides:

snap in class TraceObject

See Also:

TraceObject.get(java.lang.reflect.Field)

getBuffer

public byte[] getBuffer()

Gets the byte array buffer.

Returns:

the underlying byte array.

getOffset

public int getOffset()

Gets the byte array offset.

Returns:

the underlying byte array.

length

public int length()

Computes the size of the native form of the object. Derived classes may override this method to compute an estimated length of the contents of the object when converted to a default format.

Returns:

length of the buffer in bytes.

getClient

public short getClient()

The default getClient method returns 0. Derived classes can override this method to return a specific client type for the Native control block.

Specified by:

getClient in interface Native

Returns:

0

length

public int length(NativeFormat fmt)

Computes the size of the native form the object. Derived classes should override this method to compute the length of the contents of the object when converted according to fmt.

Specified by:

length in interface Native

Parameters:

fmt - describes native data formats, ignored.

Returns:

length of the object in bytes.

readNative

public void readNative(NativeDataInputStream in)
                throws java.io.IOException

Reads the object from a stream in native format. Derived classes should override this method to read from the stream and convert the object.

Specified by:

readNative in interface Native

Parameters:

in - the native buffered input stream.

Throws:

java.io.IOException - if an IO error occurs

writeNative

public void writeNative(NativeDataOutputStream out)
                 throws java.io.IOException

Writes the object to a stream in native format. Derived classes should override this method to convert the object and write to the stream.

Specified by:

writeNative in interface Native

Parameters:

out - the native buffered output stream.

Throws:

java.io.IOException - if an IO error occurs

readBuffer

public boolean readBuffer(NativeDataInputStream in)
                   throws java.io.IOException

Conditionally reads the buffer from a stream. If a buffer is allocated this reads enough bytes from the input stream to fill the buffer. This method allows a derived class to either read bytes directly into the underlying byte array, if present, or to convert the bytes read into objects.

Parameters:

in - the native buffered input stream.

Returns:

true if bytes were read.

Throws:

java.io.IOException - if an IO error occurs

writeBuffer

public boolean writeBuffer(NativeDataOutputStream out)
                    throws java.io.IOException

Conditionally writes the buffer to a stream. If a buffer is allocated this writes it to the output stream. This method allows a derived class to either write bytes directly from the underlying byte array, if present, or to convert and write the contents of its objects.

Parameters:

out - the native buffered output stream.

Returns:

true if bytes were written.

Throws:

java.io.IOException - if an IO error occurs