JMSStreamMessage
public class JMSStreamMessage
extends JMSMessage
implements StreamMessage
java.lang.Object
|
+----com.ibm.jms.JMSMessage
|
+----com.ibm.jms.JMSStreamMessage
A StreamMessage is used to send a stream of Java primitives.
It is filled and read sequentially. It inherits from JMSMessage
and adds a stream message body. Its methods are based largely on those found
in java.io.DataInputStream and java.io.DataOutputStream.
The primitive types can be read or written explicitly using methods for
each type. They can also be read or written generically as objects. For example,
a call to StreamMessage.writeInt(6) is equivalent
to StreamMessage.writeObject(new Integer(6)). Both
forms are provided because the explicit form is convenient for static programming
and the object form is needed when types are not known at compile time.
When the message is first created, and when clearBody() is
called, the body of the message is in write-only mode. After the first call
to the reset() method has been made, the message body is in read-only
mode. When a message has been sent the provider always calls the
reset() method to read its content. Likewise, when a message has been
received, the provider calls reset() so that the message body
is in read-only mode for the client.
If clearBody() is called on a message in read-only mode, the
message body is cleared and the message body is in write-only mode.
If a client attempts to read a message in write-only mode, a MessageNotReadableException
is thrown.
If a client attempts to write a message in read-only mode, a MessageNotWriteableException
is thrown.
Stream messages support the following conversion table. The marked cases
are supported and the unmarked cases throw a JMSException. The String to primitive
conversions throw a runtime exception if the primitives valueOf()
method does not accept it as a valid String representation of the primitive.
A value written as the row type can be read as the column type.
boolean byte short char int long float double String byte[]
--------------------------------------------------------------------------
boolean X X
byte X X X X X
short X X X X
char X X
int X X X
long X X
float X X X
double X X
String X X X X X X X X
byte[] X
--------------------------------------------------------------------------
Attempting to read a null value as a Java primitive type is treated as
calling the primitive's corresponding valueOf(String) conversion
method with a null value. Because char does not support a String conversion,
attempting to read a null value as a char throws a NullPointerException.
Methods
clearBody
public void clearBody() throws JMSException;
Clears the message body. All other parts of the message are left untouched.
- Exceptions
-
- JMSException - if the action fails to due to an internal JMS error.
readBoolean
public boolean readBoolean() throws JMSException;
Reads a boolean from the stream message.
- Returns
-
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readByte
public byte readByte() throws JMSException;
Reads a byte value from the stream message.
- Returns
-
- the next byte from the stream message as a 8-bit
byte.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readBytes
public int readBytes(byte[] value) throws JMSException;
Reads a byte array field from the stream message into the specified byte[]
object (the read buffer).
To read the field value, readBytes() should be successively called until
it returns a value less than the length of the read buffer. The values of
the bytes in the buffer following the last byte read are undefined.
If readBytes() returns a value equal to the length of the buffer, a subsequent
readBytes() call must be made. If there are no more bytes to be read this
call will return -1.
If the bytes array field value is null, readBytes() returns -1.
If the bytes array field value is empty, readBytes() returns 0.
After the first readBytes() call on a byte[] field value has been made,
the full value of the field must be read before the next field can be read.
An attempt to read the next field before that has been done will throw a MessageFormatException.
- Parameters
-
- value - the buffer into which the data is read.
- Returns
-
- the total number of bytes read into the buffer, or -1 if there is no more
data because the end of the byte field has been reached.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readChar
public char readChar() throws JMSException;
Reads a Unicode character value from the stream message.
- Returns
-
- a Unicode character from the stream message.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readDouble
public double readDouble() throws JMSException;
Reads a double from the stream message.
- Returns
-
- a double value from the stream
message.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readFloat
public float readFloat() throws JMSException;
Reads a float from the stream message.
- Returns
-
- a float value from the stream
message.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readInt
public int readInt() throws JMSException;
Reads a 32-bit integer from the stream message.
- Returns
-
- a 32-bit integer value from the stream message, interpreted as an
int.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readLong
public long readLong() throws JMSException;
Reads a 64-bit integer from the stream message.
- Returns
-
- a 64-bit integer value from the stream message, interpreted as a
long.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readObject
public Object readObject() throws JMSException;
Reads a Java object from the stream message.
This method can be used to return in 'objectified' format, an object that
had been written to the stream with the equivalent writeObject()
method call, or its equivalent primitive write() method.
- Returns
-
- a Java object from the stream message, in 'objectified' format.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageNotReadableException - if the message is in write-only mode.
readShort
public short readShort() throws JMSException;
Reads a 16-bit integer from the stream message.
- Returns
-
- a 16-bit integer from the stream message.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
readString
public String readString() throws JMSException;
Reads in a String from the stream message.
- Returns
-
- a Unicode string from the stream message.
- Exceptions
-
- JMSException - if JMS fails to read the message due to an internal JMS
error.
- MessageEOFException - if an end of message stream.
- MessageFormatException - if this type conversion is not valid.
- MessageNotReadableException - if the message is in write-only mode.
reset
public void reset() throws JMSException;
Puts the message in read-only mode, and repositions the stream to the beginning.
- Exceptions
-
- JMSException - if JMS fails to reset the message due to an internal JMS
error.
- MessageFormatException - if the message's format is not valid
toString
public String toString();
Gets a String containing a formatted version of the Message.
- Returns
-
- the String version of the message.
writeBoolean
public void writeBoolean(boolean value) throws JMSException;
Writes a boolean to the stream message.
The value true is written as the value
(byte)1; the value false is written as the value (byte)0.
- Parameters
-
- value - the boolean value to be
written.
- Exceptions
-
- JMSException - if JMS fails to write the boolean to the message due to
an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeByte
public void writeByte(byte value) throws JMSException;
Writes a byte to the stream message.
- Parameters
-
- value - the byte value to be written.
- Exceptions
-
- JMSException - if JMS fails to write the byte to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeBytes
public void writeBytes(byte[] value) throws JMSException;
Writes a byte array to the stream message.
- Parameters
-
- value - the byte array to be written.
- Exceptions
-
- JMSException - if JMS fails to write the byte array to the message due
to an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeBytes
public void writeBytes(byte[] value, int offset, int length)
throws JMSException;
Writes a portion of a byte array to the stream message.
- Parameters
-
- value - the byte array value to be written.
- offset - the initial offset within the byte array.
- length - the number of bytes to use.
- Exceptions
-
- JMSException - if JMS fails to write the byte array portion to the message
due to an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeChar
public void writeChar(char value) throws JMSException;
Writes a char to the stream message.
- Parameters
-
- value - the char value to be written.
- Exceptions
-
- JMSException - if JMS fails to write the char to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeDouble
public void writeDouble(double value) throws JMSException;
Writes a double to the stream message.
- Parameters
-
- value - the double value to be
written.
- Exceptions
-
- JMSException - if JMS fails to write the double to the message due to
an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeFloat
public void writeFloat(float value) throws JMSException;
Writes a float to the stream message.
- Parameters
-
- value - the float value to be
written.
- Exceptions
-
- JMSException - if JMS fails to write the float to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeInt
public void writeInt(int value) throws JMSException;
Writes an int to the stream message.
- Parameters
-
- value - the int to be written.
- Exceptions
-
- JMSException - if JMS fails to write the int to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeLong
public void writeLong(long value) throws JMSException;
Writes a long to the stream message.
- Parameters
-
- value - the long to be written.
- Exceptions
-
- JMSException - if JMS fails to write the long to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeObject
public void writeObject(Object value) throws JMSException;
Writes a Java object to the stream message.
This method only works for the 'objectified' primitive object types (Integer,
Double, Long...), Strings and byte arrays.
- Parameters
-
- value - the Java object to be written.
- Exceptions
-
- JMSException - if JMS fails to write the object to the message due to
an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
- MessageFormatException - if the object is not valid
writeShort
public void writeShort(short value) throws JMSException;
Write a short to the stream message.
- Parameters
-
- value - the short to be written.
- Exceptions
-
- JMSException - if JMS fails to write the short to the message due to an
internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.
writeString
public void writeString(String value) throws JMSException;
Writes a String to the stream message.
- Parameters
-
- value - the String value to be
written.
- Exceptions
-
- JMSException - if JMS fails to write the String to the message due to
an internal JMS error.
- MessageNotWriteableException - if the message is in read-only mode.