Creating XML from large result sets

We are trying to create XML docs from queries that return somewhere in the neighborhood of 13000+ rows, each with as many as 30 columns. It seems someplace deep within the xmlgen utility or the xsu methods, we throw an OutOfMemoryError. This happens whether we run as a java stored procedure, a pl/sql stored procedure, pl/sql script or java servlet. It looks like the top of the stack shows the problem occurs trying to extendCapacity in a StringBuffer. We're running 8.1.6 with java 1.2.2 and xsu 1.2. Has anyone had to query large amounts of data like this and if so, how did you go about it? Is there a slick way to break things up and then string everything back into 1 big xml doc? Any help would be greatly appreciated. Thanks.

I guess you can use pagination,
either using xsu or Top N Queries and then you could merge all the pages in an unique XML or DOM tree prior to persist it to disk.
With XSU:
Go to the following link for a clear explanation:
<http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/appdev.817/a86030/adx04x11.htm#1008351>
With Top N queries:
Go to the following thread of this forum to see a similar question I raised and it was answered in detail:
<http://technet.oracle.com:89/ubb/Forum11/HTML/004711.html>
- Jose Angel -

Similar Messages

Creating XML from query result (how?)

Hi,
It's a very general question. That is the simplest way to create XML containing data returned by a query?
I've got 3 tables: 2 primary and a linked table. One of the primary tables contains a CLOB column. I need to export the tables to a XML file. That is the simplest way to do that? (There is many XML-related functions in Oracle XML DB and I don't know which may be good.)
Thanks in advance,
JackK

That is the simplest way to create XML containing data returned by a query?Simplest:
SQL> set long 10000
SQL> set pages 5000
SQL> show user
USER is "SYS"
SQL> select XMLTYPE(CURSOR(select * from user_objects where rownum = 1)) as SIMPLEST
2 from dual;
SIMPLEST
<?xml version="1.0"?>
<ROWSET>
<ROW>
    <OBJECT_NAME>ICOL$</OBJECT_NAME>
    <OBJECT_ID>20</OBJECT_ID>
    <DATA_OBJECT_ID>2</DATA_OBJECT_ID>
    <OBJECT_TYPE>TABLE</OBJECT_TYPE>
    <CREATED>16-JAN-13</CREATED>
    <LAST_DDL_TIME>16-JAN-13</LAST_DDL_TIME>
    <TIMESTAMP>2013-01-16:10:03:32</TIMESTAMP>
    <STATUS>VALID</STATUS>
    <TEMPORARY>N</TEMPORARY>
    <GENERATED>N</GENERATED>
    <SECONDARY>N</SECONDARY>
    <NAMESPACE>1</NAMESPACE>
</ROW>
</ROWSET>Edited by: Marco Gralike on Mar 13, 2013 1:59 PM

Create a CF Query Result Set in Java

I'd like to programatically build a ColdFusion query resultset inside of a Java class and return it to the calling application. See the Java psudocode below to see what I'm talking about:
public class MyClass {
     public coldfusion.sql.QueryTable getQuery() {
          // Create a query table object
          QueryTable myTable = ..?
          // Loop through some set of instance data for my class
          for(int c = 0; c < this.myWigets.length; c++) {
               int row = c+1;
               myTable.setField(row, nameCol, this.myWigets[c].name);
               myTable.setField(row, colorCol, this.myWigets[c].color);
          return myTable;
I've had stuff like this partially working in the past but had issues with things like query of queries and such probably due to the hacks used to create the QueryTable object. I'm mainly just checking in to see if there has been any progress made in this area. To me this seems like such an obvious thing for a Java developer working within CF to want to do. I'm surprised Adobe doesn't have an officially supported API for doing this sort of thing (or maybe I'm just too dumb to find it.) A few other notes... I'm not using CFX, and I'm not starting with a java.sql.ResultSet otherwise I would use the QueryTable(java.sql.ResultSet) constructor. I need to build this thing from scratch programatically.
Thanks for your time. I hope this question makes sense to someone out there.
- Mike

I appologize. I wasn't very clear with my original question.
I'm creating an instance of my Java class from within CF using createObject("java", "com.example.MyClass"). So based on the sample code in my original post on the CF side I'd like to do something like this:
<cfscript>
     myObj = createObject("java", "com.example.MyClass");
     myObj.doSomeStuff();
     myCFQuery = myObj.getQuery(); // Return a CF query from my java class
</cfscript>
... then do stuff like ...
<cfquery name="mySortedQuery" dbtype="query">
     select     *
     from       myCFQuery
     order      by color
</cfquery>
I appriciate your suggestions so far. I have other solutions working already but they are not ideal. I was just hoping someone had a clean and as-hack-free-as-possible way of creating a ColdFusion query result set in Java and passing it back to CF.
Thanks again,
Mike

How to handle large result sets?

Hi All,
I have a large result set to be displayed to user using jsp's. Problem is that result set is too big, so I can't display all the records in a single push. I want to show the results page by page say 25 per page. Now for every page I have to fetch data from database, means there are going to be many database calls which is not advisable. Or i can cache data in a CachedRowSet to reduce database calls, but in this case you have to store all the data in memory which is not a good solution in case you have very large data sets. Can anybody suggest me a solution to this problem?

The best thing for you to do is to implmeneting paging logic in conjunction with a scrollable resultset (JDBC 2.0+).
The logic would go like this assuming 30 rows per page:
- keep track of which page the user is on (e.g. page 3)
- issue the full sql
- scroll thru only the rows in the current page (e.g. rows 90-120)
- copy the page's rows to value objects
- close the resultset, statement, and connection
In the above example, you would scroll to row 90 using rs.absolute(90).
The efficiency comes from the fact that you're using a scrollable resultset. By using this, only the rows that you scroll thru are extracted out from the database. I performed some simple testing and with my data, and the scrollable resultset was about 10x in performance.
Good luck!

Web Services with Large Result Sets

Hi,
We have an application where in a call to a web service could potentially yield a large result set. For the sake of argument, lets say that we cannot limit the result set size, i.e., by criteria narrowing or some other means.
Have any of you handled paging when using Web Services? If so can you please share your experiences considering Web Services are stateless? Any patterns that have worked? I am aware of the Value List pattern but am looking for previous experiences here.
Thanks

Joseph Weinstein wrote:
Aswin Dinakar wrote:
I ran the test again and I removed the ResultSet.Fetch_Forward and it
still gave me the same error OutOfMemory.
The problem to me is similar to what Slava has described. I am parsing
the result set in memory storing the results in a hash map and then
emptying the post processed results into a table.
The hash map turns out to be very big and jvm throws a OutOfMemory
Exception.
I am not sure how I can turn this around -
I can partition my query so that it returns smaller chunks or "blocks"
of data each time(say a page of data or two pages of data). Then I can
store a page of data in the table. The problem with this approach is
that it is not exactly transactional. Recovery would be very difficult
in this approach.
I could do this in a try catch block page by page and then the catch
could go ahead and delete the rows that got committed. The question then
becomes what if that transaction fails ?It sounds like you're committing the 'cardinal performance sin of DBMS processing',
of shovelling lots of raw data out of the DBMS, processing it in some small way,
and sending it (or some of it) back. You should instead do this processing in
a stored procedure or procedures, so the data is manipulated where it is. The
DBMS was written from the ground up to be a fast efficient set-based processor.
Using clever SQL will pay off greatly. Build your saw-mills where the trees are.
JoeYes we did think of stored procedures. Like I mentioned yesterday some of the post
processing depends on unicode and specific character sets. Java seemed ideally suited
to this since it handles these unicode characters very well and has all these libraries
we can use. Moving this to DBMS would mean we would make that proprietary (not that we
wont do it if it became absolutely essential) but its one of the reasons why the post
processing happens in java. Now that you mention it stored procedures seem the best
option.

Creating XML from JDBC resultset

Can anyone give me a pointer as the best way to create XML from a JDBC resultset. I have told that XSU cannot be used as it is vendor specific and ties us to Oracle (yawn, yawn).
Any ideas welcomed.

import javax.xml.parsers.*;
import org.w3.dom.*;
import javax.xml.dom.*;
import javax.xml.dom.source.*;
import javax.xml.dom.stream.*;
import java.sql.*;
public class CreateXML{
DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
DocumentBuilder db=dbf.newDocumentBuilder();
Document doc=db.newDocument();
Element root=doc.createElement("root_element");
// coonect to database
//get resultset metadata rsmd
while(rs.next()){
Element row=doc.createElement("row");
for(int j=1;j<=rsmd.getColumnCount();j++){
String colName=rsmd.getCoulmName(j);
String colValue=rs.getString(j);
Element e=doc.createElement(colName);
e.appendChild(doc.createTextNode(colValue));
row.appendChild(e);
root.appendChild(row);
doc.appendChild(root);
//You can now use XSLT to generate xml file thus:
TransformerFactory tmf=TransformerFactory.newInstance();
Transformer tf=tmf.newTransformer();
DOMSource source=new DOMSource(doc);
StreamResult result=new StreamResult("name of file for output");
tf.transform(source,result);
// of course exceptions will have to be caught in this code.

Reading a string containing special character from a result set

My Code....
PrintStream p = new PrintStream(fout);
if (connection == null)
connection = getConnection();
CallableStatement proc = connection.prepareCall("{call testing_read()}");
rs = proc.executeQuery();
while ( rs.next() )
String page2 = rs.getString(1);
System.out.println(page2);
rs.getString(1); is a string value eg. 'Rebekah \n Govender' that is being set in a stored procedure.
The output of my program is :'Rebekah \n Govender' , i need for it to read the special characters, and produce this output :
Rebekah
Govender
Without using a result set , it works fine.
eg.
String page2 = 'Rebekah \n Govender'
System.out.println(page2);
Will give an output of :
Rebekah
Govender
I need to read values from the results set, pls help me someone....
Please help....

String page2 = rs.getString(1).replace("\\n", "\n"); When you include source code in your posts, please enclose it in CODE tags. There's a button for that above the input textarea.
ThE-MaRaC wrote:
Hi,
you can try something like this:
import java.io.UnsupportedEncodingException;;
* Main class, manages the complete game
public class Main {
public static void main(String[] args) {
String page2 = "Rebekah \n Govender";
try {
page2 = new String(page2.getBytes("ISO-8859-1"), "ETF-8");
} catch (UnsupportedEncodingException e) {}
System.out.println(page2);
}Regards,
Hercog MarioThat is a disgusting hack which you shouldn't be recommending to anyone, and it's totally irrelevant here anyway. Also, as written, it does absolutely nothing because you misspelled "UTF-8" and you swallowed the exception that would have told you so.

Removing Duplicate records from this result set

Here is a challenge question that I was playing with one my free time during work.
I assume that you have the HR sample database somewhere around (hopefully not in production).
Let us say that you want to get employees from the employees table whose last name is similar to some other employee last name.
The easiest way is to join the two tables with a join condition that checks for the last name and the employee id. Here is what I came up with.
select e1.last_name a , e1.first_name b, e2.last_name c, e2.first_name d
from employees e1 join employees e2
on ( e1.last_name = e2.last_name and e1.employee_id <> e2.employee_id)
order by a;
The above query returns 10 rows. The first and second are essentially the same. The same applies of 3&4, 5&6, 7&8, and 9&10. The question is: is there any way that allow me to get rid of the duplicate rows using sql only from the result set of this query. I sat on it for 15 minutes and I could not figure it out. I will try looking at again after my work is over.

Example:
SQL> column a format a10
SQL> column b format a10
SQL> column c format a10
SQL> column d format a10
SQL>
SQL>
SQL> select e1.last_name a , e1.first_name b, e2.last_name c, e2.first_name d
2 from employees e1 join employees e2
3 on ( e1.last_name = e2.last_name and e1.employee_id != e2.employee_id)
4 where e1.employee_id < e2.employee_id
5 order by a;
A          B          C          D
Cambrault Gerald     Cambrault Nanette
Grant      Kimberely Grant      Douglas
King       Steven     King       Janette
Smith      Lindsey    Smith      William
Taylor     Jonathon   Taylor     Winston
SQL>

How to handle large result set of a SQL query

Hi,
I have a question about how to handle large result set of a SQL query.
My query returns more than a million records. However, the Query Template has a "row count" parameter. If I don't specify it, it by default returns only 100 lines of records in the query result. If I specify it, then it's limited to a specific number.
Is there any way to get around of this row count issue? I don't want any restriction on the number of records returned by a query.
Thanks a lot!

No human can manage that much data...in a grid, a chart, or a direct-connected link to the brain.
What you want to implement (much like other customers with similar requirements) is a drill-in and filtering model that helps the user identify and zoom in on data of relevance, not forcing them to scroll through thousands or millions of records.
You can also use a time-based paging model so that you only deal with a time "slice" at one request (e.g. an hour, day, etc...) and provide a scrolling window. This is commonly how large datasets are also dealt with in applications.
I would suggest describing your application in more detail, and we can offer design recommendations and ideas.
- Rick

Creating XML from raw data

I am trying to create xml from raw data. It works well in the format builder but
when I instanciate the MFLObject and run convert to xml, the output only contains
wrappers for my first field described in the mfl. Are there any known issues
using this progmattic conversion to XML.
My mfl is the following:
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE MessageFormat SYSTEM 'mfl.dtd'>

<MessageFormat name='BossRecord' version='2.01'>
<FieldFormat name='Header' type='String' length='102' codepage='windows-1252'/>
<StructFormat name='TransactionControlRecord' delim='999'>
<FieldFormat name='TransactionTypeNumber' type='String' length='3' codepage='windows-1252'/>
<FieldFormat name='TransactionData' type='String' codepage='windows-1252'>
<LenField type='Numeric' length='4'/>
</FieldFormat>
</StructFormat>
<StructFormat name='Generic' repeat='*'>
<FieldFormat name='GenericTypeNumber' type='String' length='3' codepage='windows-1252'/>
<FieldFormat name='GenericData' type='String' codepage='windows-1252'>
<LenField type='Numeric' length='4'/>
</FieldFormat>
</StructFormat>
<FieldFormat name='IgnoreTheRest' type='Filler' optional='y' length='1' repeat='*'>

</FieldFormat>
</MessageFormat>
Are there any issues with this that are easy to spot?
Here is some sample output:
_BossRecordDoc : <BossRecord>
<Header>0601uskyloupw7vu0 IBVRTR 000006RSQ1010246000000000000020436000001-01-01-00.00.00.00000000000100170</Header>
<Header>90100581D4EBC00AA3C18629ACA0004AC02E54BD289357023141961111F1111 99900207141D4EBC00AA3C18629ACA0004AC0</Header>
<Header>2E54BD2893570231RIBBONS & BUTTONS 9 00000000000010.50CAD00000000000000.5</Header>
<Header>0USD00000000000000.00USD00000000000077.00CAD 0CAUS00000000000000.91KGSA215D100CF3C18619AC</Header>
<Header>90004AC02E54B 01 0001-0</Header>
<Header>1-012003-04-072003-06-2501P/P03003984196000010100000000000000.00CAD 00
FR00000000000000</Header>
<Header>.0000000000000000000.00KGS00000000000000.00USD 00UPS T1</Header>
<Header>0001-01-010001-01-01 0 000000000000000.00000000000000000.00USD0</Header>
<Header>000000000000000.00 1 22222222222220 0100304061DC30500AA3C18629ACA</Header>
<Header>0004AC02E54B1D4EBC00AA3C18629ACA0004AC02E54B</Header>
<Header> 0010001-01-01 00000000000000.00USD00</Header>
<Header>000000000000.00CAD00000000000010.00CAD</Header>
<Header> 00000000000010.00CAD000000000000000010001-01-01K00404862A8D2C00AA3C186</Header>
<Header>29ACA0004AC02E54B1DC30500AA3C18629ACA0004AC02E54B001 PURPLE RIBBONS</Header>
It just keeps finding my first record instead of finding the remaing structure.
I appreciate any help.
Thanks,
Michael

Okay, I've got some coding off a site that looks like it will do what I want. It's quite a robust applications which will do more than I need but as long as it does at least what I want, i could care less. As it will extract files from the datastream for me, it is going to save them to disk.
I believe I have to specify a directory to save it to. I believe this is the line I'm going to modify, so assuming that's the case, how do I specify a directory here:
private File fileOutPutDirectory = null;
Do I have to use absolute paths or can I use relative. Also, what directory construct is expected by java? Anyone with an example of what urls are supposed to look like in this case?
Thanks,
destin

How to create a browsable, distributable result set?

I want do develop a web application, which must be able to browse (previous page, next page) in large result sets. The web application is distributed on several servers (persistent session). What is the way to handle this?

The web application is distributed on
several servers (persistent session). What is the way
to handle this?Can you explain what a persistent session distributed on serveral servers means?

I-bot not emailing when report returns large result set..

Hi,
I am trying to set up an i-bot to run daily and email the results to the user. Assuming the report in question is Report_A.
Report_A returns around 60000 rows of data without any filter condition. When I tried to set up thei-bot for Report_A (No filter conditions on the report) the ibot is publishing results to dashboard but is not delivering via email. When I introduce a filter in Report_A to reduce the data returned then everything works fine and email is being sent out successfully.
So
1) Is there a size limit for i-bots to deliver by email?
2) Is there a way to increase the limits if any so the report can be emailed even when returning large result sets?
Please let me know.

Sorry for late reply
Below is the log file for one of the i-bots. Now I am getting an error message "***kmsgPortalGoRequestHasBeenCancelled: message text not found ***" and the i-bot alert message shows as "Cancelled".
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:04.551
[nQSError: 77006] Oracle BI Presentation Server Error: A fatal error occurred while processing the request. The server responded with: ***kmsgPortalGoRequestHasBeenCancelled: message text not found ***
Error Codes: YLKKAV7S
Error Codes: AGEGTYVF
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:04.553
iBotID: /shared/_ibots/common/TM/Claims Report
...Trying iBot Get Response Content loop again.
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:04.554
... Sleeping for 8 seconds.
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:12.642
[nQSError: 77006] Oracle BI Presentation Server Error: A fatal error occurred while processing the request. The server responded with: ***kmsgPortalGoRequestHasBeenCancelled: message text not found ***
Error Codes: YLKKAV7S
Error Codes: AGEGTYVF
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:12.644
iBotID: /shared/_ibots/common/TM/Claims Report
...Trying iBot Get Response Content loop again.
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:12.644
... Sleeping for 6 seconds.
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:18.730
[nQSError: 77006] Oracle BI Presentation Server Error: A fatal error occurred while processing the request. The server responded with: ***kmsgPortalGoRequestHasBeenCancelled: message text not found ***
Error Codes: YLKKAV7S
Error Codes: AGEGTYVF
+++ ThreadID: f3c6cb90 : 2010-12-17 23:55:18.734
iBotID: /shared/_ibots/common/TM/Claims Report
Exceeded number of request retries.

Displaying large result sets in Table View u0096 request for patterns

When providing a table of results from a large data set from SAP, care needs to be taken in order to not tax the R/3 database or the R/3 and WAS application servers. Additionally, in terms of performance, results need to be displayed quickly in order to provide sub-second response times to users.
This post is my thoughts on how to do this based on my findings that the Table UI element cannot send an event to retrieve more data when paging down through data in the table (hopefully a future feature of the Table UI Element).
Approach:
For data retrieval, we need to have an RFC with search parameters that retrieves a maximum number of records (say 200) and a flag whether 200 results were returned.
In terms of display, we use a table UI Element, and bind the result set to the table.
For sorting, when they sort by a column, if we have less than the maximum search results, we sort the result set we already have (no need to go to SAP), but otherwise the RFC also needs to have sort information as parameters so that sorting can take place during the database retrieval. We sort it during the SQL select so that we stop as soon as we hit 200 records.
For filtering, again, if less than 200 results, we just filter the results internally, otherwise, we need to go to SAP, and the RFC needs to have this parameterized also.
If the requirement is that the user must look at more than 200 results, we need to have a button on the screen to fetch the next 200 results. This implies that the RFC will also need to have a start point to return results from. Similarly, a previous 200 results button would need to be enabled once they move beyond the initial result set.
Limitations of this are:
1.     We need to use custom RFC function as BAPIs dont generally provide this type of sorting and limiting of data.
2.     Functions need to directly access tables in order to do sorting at the database level (to reduce memory consumption).
3.     Its not a great interface to add buttons to Get next/previous set of 200.
4.     Obviously, based on where you are getting the data from, it may be better to load the data completely into an internal table in SAP, and do sorting and filtering on this, rather than use the database to do it.
Does anyone have a proven pattern for doing this or any improvements to the above design? Im sure SAP-CRM must have to do this, or did they just go with a BSP view when searching for customers?
Note I noticed there is a pattern for search results in some documentation, but it does not exist in the sneak preview edition of developer studio. Has anyone had in exposure to this?
Update - I'm currently investigating whether we can create a new value node and use a supply function to fill the data. It may be that when we bind this to the table UI element, that it will call this incrementally as it requires more data and hence could be a better solution.

Hi Matt,
i'm afraid, the supplyFunction will not help you to get out of this, because it's only called, if the node is invalid or gets invalidated again. The number of elements a node contains defines the number of elements the table uses for the determination of the overall number of table rows. Something quite similar to what you want does already exist in the WD runtime for internal usage. As you've surely noticed, only "visibleRowCount" elements are initially transferred to the client. If you scroll down one or multiple lines, the following rows are internally transferred on demand. But this doesn't help you really, since:
1. You don't get this event at all and
2. Even if you would get the event, since the number of node elements determines the table's overall rows number, the event would never request to load elements with an index greater than number of node elements - 1.
You can mimic the desired behaviour by hiding the table footer and creating your own buttons for pagination and scrolling.
Assume you have 10 displayed rows and 200 overall rows, What you need to be able to implement the desired behaviour is:
1. A context attribute "maxNumberOfExpectedRows" type int, which you would set to 200.
2. A context attribute "visibleRowCount" type int, which you would set to 10 and bind to table's visibleRowCount property.
3. A context attribute "firstVisibleRow" type int, which you would set to 0 and bind to table's firstVisibleRow property.
4. The actions PageUp, PageDown, RowUp, RowDown, FirstRow and LastRow, which are used for scrolling and the corresponding buttons.
The action handlers do the following:
PageUp: firstVisibleRow -= visibleRowCount (must be >=0 of course)
PageDown: firstVisibleRow += visibleRowCount (first + visible must be < maxNumberOfExpectedRows)
RowDown/Up: firstVisibleRow++/-- with the same restrictions as in page "mode"
FirstRow/LastRow is easy, isn't it?
Since you know, which sections of elements has already been "loaded" into the dataSource-node, you can fill the necessary sections on demand, when the corresponding action is triggered.
For example, if you initially display elements 0..9 and goto last row, you load from maxNumberOfExpected (200) - visibleRows (10) entries, so you would request entries 190 to 199 from the backend.
A drawback is, that the BAPIs/RFCs still have to be capable to process such "section selecting".
Best regards,
Stefan
PS: And this is meant as a workaround and does not really replace your pattern request.

Not able to create XML from an existing relational database

Hi,
I am trying to create and xml from an existing relational database. I am not able to get any XML data, I receive "XMLTYPE()" as the result.
Here's the query -
SQL> select o.order_id, XMLELEMENT("order", XMLATTRIBUTES(o.order_id as ID)) AS "result" from order_
info o where order_id=2793;
ORDER_ID
result()
+2793+
XMLTYPE()
I was expecting to get +<order id=2793 />+ instead of XMLTYPE().
I am using -
SQLPlus: Release 9.0.1.0.1*
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
I have also run some checks to confirm XML DB installation -
SQL> select 1 from all_users where username = 'XDB';
+1+
+1+
SQL> desc RESOURCE_VIEW;
Name                                      Null?    Type
RES                                                SYS.XMLTYPE
ANY_PATH                                           VARCHAR2(4000)
RESID                                              RAW(16)
I think, I have something wrong with installation or configuration.
Any idea about what have I done wrong here?

Works fine now. Got the result "<order ID="2793"></order>".
Thanks. :-)

Create XML from XSD

Hi,
Is it possible to create and populate XML from an XSD without knowing what the XSD elements are beforehand (all the examples appear to know what the input XSD will be, and therefore know what the set and get methods should be called)?
Can a user browse for an xsd to input, and the java will dynamically create the get methods, and be able to create instances and populate variables before converting to XML?
I have looked at JAXB and the purchase.order examples mainly, and it appears the input XSD was known before writing the java to populate the variables.
Thanks
John

Hi,
Is it possible to create and populate XML from an XSD
without knowing what the XSD elements are beforehand
(all the examples appear to know what the input XSD
will be, and therefore know what the set and get
methods should be called)? I think it is possible--you would have to recompile each time (unless you can dynamically recompile, which would be neat), but using the classes getMethod() function, you can list all the methods. You would then have to do some tricky logic to determine which of the getMethods you want (for example NOT getClass()), and you can basically call them in sequence. You also need to worry about handling lists & recursively call xxxType classes.
I'm experimenting with this, and it can get a little frustrating because there are a lot of odd cases to handle (for example, while setting the elements of a list, you need to actually get the list & add elements to it), but I think it's possible.
>
Can a user browse for an xsd to input, and the java
will dynamically create the get methods, and be able
to create instances and populate variables before
converting to XML?
What I'm puzzled about is where you'd get the data to populate the variables? Perhaps a database, or a bean? If you just want to make a test xml file, then it doesn't matter, but with real data, I think you'd still have to change how you actually get the variables you want to populate the xml file with, right? In other words, if your schema changed, the parameters you're passing to the set methods would change as well.
Maybe we'll see some more packages in the future to make this task easier.

Creating XML from large result sets

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