com.ibm.mq.headers

Class MQHeaderIterator

java.lang.Object

com.ibm.mq.jmqi.JmqiObject

com.ibm.mq.headers.MQHeaderIterator

All Implemented Interfaces:

java.util.Iterator

public class MQHeaderIterator
extends com.ibm.mq.jmqi.JmqiObject
implements java.util.Iterator

An MQHeaderIterator returns headers one by one from a message. This class provides an easy way for an application to access header content in a message.

Examples

Print out all the headers in a message

   DataInput message = ...
   MQHeaderIterator it = new MQHeaderIterator (message);
   
   while (it.hasNext ())
   {
       MQHeader header = it.nextHeader ();
   
       System.out.println ("Header (type " + header.type + "): " + header); 
   }
 

Skip over all headers in a message

   DataInput message = ...
   MQHeaderIterator it = new MQHeaderIterator (message);
   it.skipHeaders ();
 

The message read cursor is now positioned immediately after the last header.

Extract the body of the message as a String, skipping any headers present

   DataInput message = ...;
   String body = new MQHeaderIterator (message).getBodyAsText ();
 

The getBodyAsBytes method is similar but returns the message body as a byte array.

For the ability to search directly for particular headers, remove headers from a message, and other goodies, see MQHeaderList.

See Also:

MQHeaderList

Field Summary

Fields inherited from class com.ibm.mq.jmqi.JmqiObject

COMP_JM, COMP_JN, COMP_JO

Constructor Summary

Constructors

Constructor and Description
MQHeaderIterator(java.io.DataInput message) Constructs an MQHeaderIterator around a message.
MQHeaderIterator(java.io.DataInput message, java.lang.String format, int encoding, int characterSet) Constructs an MQHeaderIterator around a message or byte stream.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	getBody() Skips any remaining headers.
byte[]	getBodyAsBytes() Skips any remaining headers
java.lang.String	getBodyAsText() Skips any remaining headers
boolean	hasNext() Indicates whether there is another Header
java.lang.Object	next() get the next Header
MQHeader	nextHeader() Synonym for the next method, but typed to return MQHeader.
java.io.DataInput	skipHeaders() Skips all headers remaining from the current message position.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

MQHeaderIterator

public MQHeaderIterator(java.io.DataInput message)

Constructs an MQHeaderIterator around a message. Header content will be read from the current position of the message read cursor. The initial format, encoding and CCSID used to interpret the content are taken from the MQMD fields in the message.

Parameters:

message - the message.

MQHeaderIterator

public MQHeaderIterator(java.io.DataInput message,
                        java.lang.String format,
                        int encoding,
                        int characterSet)

Constructs an MQHeaderIterator around a message or byte stream. Header content will be read from the current position of the message read cursor or position in the byte stream. The initial format encoding and CCSID used to interpret the content are taken from the arguments.

Parameters:

message - the message.

format - the message format (see CMQC.MQFMT_* for values)

encoding - the numeric encoding. see (CMQC.MQENC_* for values)

characterSet - the Coded Character Set Identifier.

Method Detail

hasNext

public boolean hasNext()

Indicates whether there is another Header

Specified by:

hasNext in interface java.util.Iterator

Returns:

true or false as appropriate

next

public java.lang.Object next()

get the next Header

Specified by:

next in interface java.util.Iterator

Returns:

the next header

nextHeader

public MQHeader nextHeader()

Synonym for the next method, but typed to return MQHeader.

Returns:

the next header

skipHeaders

public java.io.DataInput skipHeaders()
                              throws MQDataException,
                                     java.io.IOException

Skips all headers remaining from the current message position.

Returns:

the original message or byte stream positioned immediately following the last header.

Throws:

MQDataException

java.io.IOException

getBody

public java.lang.Object getBody()
                         throws MQDataException,
                                java.io.IOException

Skips any remaining headers.

Returns:

the message body as either a String or a byte array according to the format of the last header. If the format is MQFMT_STRING, the body is a String; otherwise it is a byte array.

Throws:

MQDataException

java.io.IOException

getBodyAsBytes

public byte[] getBodyAsBytes()
                      throws MQDataException,
                             java.io.IOException

Skips any remaining headers

Returns:

the message body as a byte array. This method returns a byte array even if the last format is MQFMT_STRING.

Throws:

MQDataException

java.io.IOException

getBodyAsText

public java.lang.String getBodyAsText()
                               throws MQDataException,
                                      java.io.IOException

Skips any remaining headers

Returns:

the message body as a String. This method returns a String regardless of the format field of the last header. The byte content of the message body is converted into a String using the CCSID indicated by the last header (or by the MQMD, if there are no headers, or no headers with chaining information).

Throws:

MQDataException

java.io.IOException