Re: How to convert Map to xml based on Schema.

From:
Mausam <mausamhere@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 19 Nov 2012 02:22:46 -0800 (PST)
Message-ID:
<7d2a2881-e3fe-4d24-9f59-47b23041422e@googlegroups.com>
Thanks a lot Arne for taking up the time to write code. However we do not w=
ant to generate java files everytime we get a different schema. Schema and =
values are not fixed to one or two datatypes.

On Monday, November 19, 2012 8:12:15 AM UTC+5:30, Arne Vajh=F8j wrote:

On 11/18/2012 4:15 PM, Arne Vajh=EF=BF=BDj wrote:
 

On 11/17/2012 1:52 AM, Mausam wrote:

 

I have a Map (it can be nested map, containing of maps) and a schema.

 

Keys in Map represent element/attribute name of the schema and an

 

entry in Map will be at same depth as an element defined in schema

 

 

I need help in generating xml from the map as per the schema provided,

 

without generating new files (as e.g Jaxb would require) Sample

 

schema/map provided below

 

 

e.g Map =

 

[dept=[deptno="10",dname="ABC",loc="XYZ",emps=[[empno=1000=

,ename="Albert"],[empno=2000,ename="John"]]]]

 

and schema will be

 

 

e.g Schema

 

<?xml version="1.0" encoding="windows-1252" ?>

 

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"

 

elementFormDefault="qualified">

 

   <xsd:element name="depts">

 

     <xsd:complexType>

 

       <xsd:sequence>

 

         <xsd:element name="dept" maxOccurs="unbounded">

 

           <xsd:complexType>

 

             <xsd:sequence>

 

               <xsd:element name="deptno" type="xsd:string"/><!-- =

This

 

simple element e.g can be attribute in some schema-->

 

               <xsd:element name="dname" type="xsd:string"/>

 

               <xsd:element name="emps" maxOccurs="unbounded"

 

minOccurs="0">

 

                 <xsd:complexType>

 

                   <xsd:sequence>

 

                     <xsd:element name="empno" type="xsd:string"/>

 

                     <xsd:element name="ename" type="xsd:string"/>

 

                   </xsd:sequence>

 

                 </xsd:complexType>

 

               </xsd:element>

 

             </xsd:sequence>

 

           </xsd:complexType>

 

         </xsd:element>

 

       </xsd:sequence>

 

     </xsd:complexType>

 

   </xsd:element>

 

</xsd:schema>

 

 

I would probably:

 

- generate a Java class from the schema (xjc)

 

- populate from Map to an instance of that class via recursion

 

   and reflection

 

- serialize instance to XML via JAXB

 

 

If you have high performance requirements, then you may need

 

to do some custom coding.

 
 
 
Demo with Map:
 
 
 
import java.beans.IntrospectionException;
 
import java.beans.PropertyDescriptor;
 
import java.lang.reflect.InvocationTargetException;
 
import java.util.HashMap;
 
import java.util.Map;
 
 
 
public class AutoMapper {
 
    private static Object xctor(Object o, String propnam) throws
 
IntrospectionException, InstantiationException, IllegalAccessException {
 
        PropertyDescriptor pd = new PropertyDescriptor(propnam, o.getClass())=
;

 
        return pd.getPropertyType().newInstance();
 
    }
 
    private static void xset(Object o, String propnam, Object val) throws
 
IntrospectionException, IllegalArgumentException,
 
IllegalAccessException, InvocationTargetException {
 
        PropertyDescriptor pd = new PropertyDescriptor(propnam, o.getClass())=
;

 
        pd.getWriteMethod().invoke(o, val);
 
    }
 
    @SuppressWarnings("unchecked")
 
    private static void map(Map<String,Object> m, Object o) throws
 
IllegalArgumentException, IntrospectionException,
 
IllegalAccessException, InvocationTargetException, InstantiationException=

 {

 
        for(String key : m.keySet()) {
 
            Object val = m.get(key);
 
            if(val instanceof Map) {
 
                Object o2 = xctor(o, key);
 
                map((Map<String, Object>) val, o2);
 
                xset(o, key, o2);
 
            } else {
 
                xset(o, key, val);
 
            }
 
        }
 
    }
 
    public static void main(String[] args) throws Exception {
 
        Map<String,Object> m2 = new HashMap<String,Object>();
 
        m2.put("iv", 456);
 
        m2.put("xv", 123.456);
 
        Map<String,Object> m = new HashMap<String,Object>();
 
        m.put("iv", 123);
 
        m.put("sv", "ABC");
 
        m.put("cv", m2);
 
        Data o = new Data();
 
        System.out.println(m);
 
        map(m, o);
 
        System.out.println(o);
 
    }
 
}
 
 
 
class Data {
 
    private int iv;
 
    private String sv;
 
    private SubData cv;
 
    public int getIv() {
 
        return iv;
 
    }
 
    public void setIv(int iv) {
 
        this.iv = iv;
 
    }
 
    public String getSv() {
 
        return sv;
 
    }
 
    public void setSv(String sv) {
 
        this.sv = sv;
 
    }
 
    public SubData getCv() {
 
        return cv;
 
    }
 
    public void setCv(SubData cv) {
 
        this.cv = cv;
 
    }
 
    @Override
 
    public String toString() {
 
        return "(iv=" + iv + ",sv=" + sv + ",cv=" + cv + ")";
 
    }
 
}
 
 
 
class SubData {
 
    private int iv;
 
    private double xv;
 
    public int getIv() {
 
        return iv;
 
    }
 
    public void setIv(int iv) {
 
        this.iv = iv;
 
    }
 
    public double getXv() {
 
        return xv;
 
    }
 
    public void setXv(double xv) {
 
        this.xv = xv;
 
    }
 
    @Override
 
    public String toString() {
 
        return "(iv=" + iv + ",xv=" + xv + ")";
 
    }
 
}
 
 
 
Arne
 
 
 
PS: It looks like you may really need to convert List not Map.

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