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Posted to users@cxf.apache.org by Kaleb Walton <kd...@us.ibm.com> on 2007/11/28 16:13:57 UTC
Example of JAXB and HashMap serialization?
I'm writing documentation for how to write services and got to a point
where I have to say "Do not use HashMap's in any of your services as CXF +
JAXB does not support serializing HashMaps". I'd rather not have to say
that - are there any examples out there of how to get HashMaps to serialize
using CXF + JAXB?
I've seen the XmlAdapter stuff out there but that doesn't suit my needs for
two reasons:
1) We don't use annotations
2) We want to use HashMaps, not pseudo-maps
I may be misunderstanding the solutions pointed out in the articles, if so
please help me see the light!
Regards,
Kaleb
Re: Example of JAXB and HashMap serialization?
Posted by Kaleb Walton <kd...@us.ibm.com>.
Chris,
Thank you for the detailed example! I'll definitely look into this
implementation when the need arises in the future (right now we're getting
by without them, but I know we'll need them at some point). Glad we're not
the only ones who thought this was an important missing piece.
Regards,
Kaleb
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| From: |
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>--------------------------------------------------------------------------------------------------------------------------------------------------|
|Chris McClelland <ap...@m3.ath.cx> |
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| To: |
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|cxf-user@incubator.apache.org |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| Date: |
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|11/29/2007 07:07 PM |
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| Subject: |
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|Re: Example of JAXB and HashMap serialization? |
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Kaleb,
This is an interesting question, and one which I have encountered twice
in the last week. I came up with a solution which works using
@XmlAdaptor (wait, don't write it off just yet...)
First a caveat: this only works if you represent the map as a *wrapped*
list of {k,v} pairs. Probably the simplest XML representation would be:
<M xmlns="http://...">
<MyMap>
<A value="1" key="A"/>
<A value="3" key="C"/>
<A value="2" key="B"/>
</MyMap>
</M>
By wrapped, I mean the model must be something like M=(A+), and not
M=(A+, B). I'm not saying the latter is impossible, only that I couldn't
get it to work in the time I had had on this.
So, let's look at class 'M', which is the class containing the map:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "M")
public class M {
@XmlElement(name = "MyMap", required = true)
@XmlJavaTypeAdapter(MapAdaptor.class)
private final Map<String, String> a = new HashMap<String, String>();
public Map<String, String> getA() {
return this.a;
}
}
Now we need to implement MapAdaptor, which maps the Map to something
JAXB understands:
public class MapAdaptor extends XmlAdapter<MyMap, Map<String,String>> {
@Override
public MyMap marshal(Map<String,String> v) throws Exception {
MyMap myMap = new MyMap();
List<A> aList = myMap.getA();
for ( Map.Entry<String,String> e : v.entrySet() ) {
aList.add(new A(e.getKey(), e.getValue()));
}
return myMap;
}
@Override
public Map<String,String> unmarshal(MyMap v) throws Exception {
Map<String,String> map = new HashMap<String,String>();
for ( A e : v.getA() ) {
map.put(e.getKey(), e.getValue());
}
return map;
}
}
So that maps Map<String, String> to a new class, MyMap, which might look
like this:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "MyMap")
public class MyMap {
@XmlElement(name = "A", required = true)
private final List<A> a = new ArrayList<A>();
public List<A> getA() {
return this.a;
}
}
And finally, each item in the list is represented by a new class A:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "A")
public class A {
@XmlAttribute(name = "key", required = true)
private final String key;
@XmlAttribute(name = "value", required = true)
private final String value;
public A(String key, String value) {
this.key = key;
this.value = value;
}
public A() {
this.key = null;
this.value = null;
}
public String getKey() {
return key;
}
public String getValue() {
return value;
}
}
This is a functional, albeit circuitous and slightly naïve (all maps are
Map<String,String>) solution to your problem. So where does that leave
us? JAXBIntros supports all these annotations except
@XmlJavaTypeAdapter. But adding support for it would be fairly trivial,
and if you are happy with the overall picture of what I describe above,
then I'll happily add support for @XmlJavaTypeAdapter to JAXBIntros and
ask the JBoss guys to commit it. Then you'd be able to get the above
scenario working even if you did not have the source to the M class.
- Chris
Kaleb Walton wrote:
> Glen,
>
> Thanks for the response. It is a JAXB specific question and yes I did
> google for both of those but they turn up pages related to an XmlAdapter
> which doesn't seem like the right solution. In addition we don't use
> annotations (we use the InlineAnnotationsReader from JBoss) so I'm not
sure
> how I'd configure the XmlAdapter anyways. I was looking for a simpler
> solution if one was available - just feeling out the CXF group to see if
> anyone else has solved this with JAXB+CXF.
>
> Regards,
> Kaleb
>
>
> |------------>
> | From: |
> |------------>
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |Glen Mazza <gl...@verizon.net>
|
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | To: |
> |------------>
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |cxf-user@incubator.apache.org
|
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | Date: |
> |------------>
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |11/28/2007 11:28 PM
|
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | Subject: |
> |------------>
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
> |Re: Example of JAXB and HashMap serialization?
|
>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
>
>
>
>
>
> Are you sure this is a CXF/JAXB-specific question instead of a more
> generic JAXB question? (CXF's JAXB is the same as GlassFish Metro's,
> for example.) Does googling "JAXB" and "HashMap" get you anything
> useful?
>
> Glen
>
> Am Mittwoch, den 28.11.2007, 10:13 -0500 schrieb Kaleb Walton:
>> I'm writing documentation for how to write services and got to a point
>> where I have to say "Do not use HashMap's in any of your services as CXF
> +
>> JAXB does not support serializing HashMaps". I'd rather not have to say
>> that - are there any examples out there of how to get HashMaps to
> serialize
>> using CXF + JAXB?
>>
>> I've seen the XmlAdapter stuff out there but that doesn't suit my needs
> for
>> two reasons:
>>
>> 1) We don't use annotations
>> 2) We want to use HashMaps, not pseudo-maps
>>
>> I may be misunderstanding the solutions pointed out in the articles, if
> so
>> please help me see the light!
>>
>> Regards,
>> Kaleb
>
>
Re: Example of JAXB and HashMap serialization?
Posted by Chris McClelland <ap...@m3.ath.cx>.
Kaleb,
This is an interesting question, and one which I have encountered twice
in the last week. I came up with a solution which works using
@XmlAdaptor (wait, don't write it off just yet...)
First a caveat: this only works if you represent the map as a *wrapped*
list of {k,v} pairs. Probably the simplest XML representation would be:
<M xmlns="http://...">
<MyMap>
<A value="1" key="A"/>
<A value="3" key="C"/>
<A value="2" key="B"/>
</MyMap>
</M>
By wrapped, I mean the model must be something like M=(A+), and not
M=(A+, B). I'm not saying the latter is impossible, only that I couldn't
get it to work in the time I had had on this.
So, let's look at class 'M', which is the class containing the map:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "M")
public class M {
@XmlElement(name = "MyMap", required = true)
@XmlJavaTypeAdapter(MapAdaptor.class)
private final Map<String, String> a = new HashMap<String, String>();
public Map<String, String> getA() {
return this.a;
}
}
Now we need to implement MapAdaptor, which maps the Map to something
JAXB understands:
public class MapAdaptor extends XmlAdapter<MyMap, Map<String,String>> {
@Override
public MyMap marshal(Map<String,String> v) throws Exception {
MyMap myMap = new MyMap();
List<A> aList = myMap.getA();
for ( Map.Entry<String,String> e : v.entrySet() ) {
aList.add(new A(e.getKey(), e.getValue()));
}
return myMap;
}
@Override
public Map<String,String> unmarshal(MyMap v) throws Exception {
Map<String,String> map = new HashMap<String,String>();
for ( A e : v.getA() ) {
map.put(e.getKey(), e.getValue());
}
return map;
}
}
So that maps Map<String, String> to a new class, MyMap, which might look
like this:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "MyMap")
public class MyMap {
@XmlElement(name = "A", required = true)
private final List<A> a = new ArrayList<A>();
public List<A> getA() {
return this.a;
}
}
And finally, each item in the list is represented by a new class A:
@XmlAccessorType(XmlAccessType.FIELD)
@XmlRootElement(name = "A")
public class A {
@XmlAttribute(name = "key", required = true)
private final String key;
@XmlAttribute(name = "value", required = true)
private final String value;
public A(String key, String value) {
this.key = key;
this.value = value;
}
public A() {
this.key = null;
this.value = null;
}
public String getKey() {
return key;
}
public String getValue() {
return value;
}
}
This is a functional, albeit circuitous and slightly naïve (all maps are
Map<String,String>) solution to your problem. So where does that leave
us? JAXBIntros supports all these annotations except
@XmlJavaTypeAdapter. But adding support for it would be fairly trivial,
and if you are happy with the overall picture of what I describe above,
then I'll happily add support for @XmlJavaTypeAdapter to JAXBIntros and
ask the JBoss guys to commit it. Then you'd be able to get the above
scenario working even if you did not have the source to the M class.
- Chris
Kaleb Walton wrote:
> Glen,
>
> Thanks for the response. It is a JAXB specific question and yes I did
> google for both of those but they turn up pages related to an XmlAdapter
> which doesn't seem like the right solution. In addition we don't use
> annotations (we use the InlineAnnotationsReader from JBoss) so I'm not sure
> how I'd configure the XmlAdapter anyways. I was looking for a simpler
> solution if one was available - just feeling out the CXF group to see if
> anyone else has solved this with JAXB+CXF.
>
> Regards,
> Kaleb
>
>
> |------------>
> | From: |
> |------------>
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |Glen Mazza <gl...@verizon.net> |
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | To: |
> |------------>
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |cxf-user@incubator.apache.org |
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | Date: |
> |------------>
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |11/28/2007 11:28 PM |
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |------------>
> | Subject: |
> |------------>
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
> |Re: Example of JAXB and HashMap serialization? |
> >--------------------------------------------------------------------------------------------------------------------------------------------------|
>
>
>
>
>
> Are you sure this is a CXF/JAXB-specific question instead of a more
> generic JAXB question? (CXF's JAXB is the same as GlassFish Metro's,
> for example.) Does googling "JAXB" and "HashMap" get you anything
> useful?
>
> Glen
>
> Am Mittwoch, den 28.11.2007, 10:13 -0500 schrieb Kaleb Walton:
>> I'm writing documentation for how to write services and got to a point
>> where I have to say "Do not use HashMap's in any of your services as CXF
> +
>> JAXB does not support serializing HashMaps". I'd rather not have to say
>> that - are there any examples out there of how to get HashMaps to
> serialize
>> using CXF + JAXB?
>>
>> I've seen the XmlAdapter stuff out there but that doesn't suit my needs
> for
>> two reasons:
>>
>> 1) We don't use annotations
>> 2) We want to use HashMaps, not pseudo-maps
>>
>> I may be misunderstanding the solutions pointed out in the articles, if
> so
>> please help me see the light!
>>
>> Regards,
>> Kaleb
>
>
Re: Example of JAXB and HashMap serialization?
Posted by Kaleb Walton <kd...@us.ibm.com>.
Glen,
Thanks for the response. It is a JAXB specific question and yes I did
google for both of those but they turn up pages related to an XmlAdapter
which doesn't seem like the right solution. In addition we don't use
annotations (we use the InlineAnnotationsReader from JBoss) so I'm not sure
how I'd configure the XmlAdapter anyways. I was looking for a simpler
solution if one was available - just feeling out the CXF group to see if
anyone else has solved this with JAXB+CXF.
Regards,
Kaleb
|------------>
| From: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|Glen Mazza <gl...@verizon.net> |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| To: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|cxf-user@incubator.apache.org |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| Date: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|11/28/2007 11:28 PM |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| Subject: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|Re: Example of JAXB and HashMap serialization? |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
Are you sure this is a CXF/JAXB-specific question instead of a more
generic JAXB question? (CXF's JAXB is the same as GlassFish Metro's,
for example.) Does googling "JAXB" and "HashMap" get you anything
useful?
Glen
Am Mittwoch, den 28.11.2007, 10:13 -0500 schrieb Kaleb Walton:
>
> I'm writing documentation for how to write services and got to a point
> where I have to say "Do not use HashMap's in any of your services as CXF
+
> JAXB does not support serializing HashMaps". I'd rather not have to say
> that - are there any examples out there of how to get HashMaps to
serialize
> using CXF + JAXB?
>
> I've seen the XmlAdapter stuff out there but that doesn't suit my needs
for
> two reasons:
>
> 1) We don't use annotations
> 2) We want to use HashMaps, not pseudo-maps
>
> I may be misunderstanding the solutions pointed out in the articles, if
so
> please help me see the light!
>
> Regards,
> Kaleb
Re: Example of JAXB and HashMap serialization?
Posted by Glen Mazza <gl...@verizon.net>.
Are you sure this is a CXF/JAXB-specific question instead of a more
generic JAXB question? (CXF's JAXB is the same as GlassFish Metro's,
for example.) Does googling "JAXB" and "HashMap" get you anything
useful?
Glen
Am Mittwoch, den 28.11.2007, 10:13 -0500 schrieb Kaleb Walton:
>
> I'm writing documentation for how to write services and got to a point
> where I have to say "Do not use HashMap's in any of your services as CXF +
> JAXB does not support serializing HashMaps". I'd rather not have to say
> that - are there any examples out there of how to get HashMaps to serialize
> using CXF + JAXB?
>
> I've seen the XmlAdapter stuff out there but that doesn't suit my needs for
> two reasons:
>
> 1) We don't use annotations
> 2) We want to use HashMaps, not pseudo-maps
>
> I may be misunderstanding the solutions pointed out in the articles, if so
> please help me see the light!
>
> Regards,
> Kaleb
RE: Example of JAXB and HashMap serialization?
Posted by Kaleb Walton <kd...@us.ibm.com>.
Great, thank you for the clarification - I hope 'supposedly' turns into
'definitely' ;-). We can hold out for the maturation of the trunk and some
examples to bubble up before diving in.
Regards,
Kaleb
|------------>
| From: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|"Benson Margulies" <bi...@basistech.com> |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| To: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|<cx...@incubator.apache.org> |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| Date: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|11/28/2007 12:55 PM |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|------------>
| Subject: |
|------------>
>--------------------------------------------------------------------------------------------------------------------------------------------------|
|RE: Example of JAXB and HashMap serialization? |
>--------------------------------------------------------------------------------------------------------------------------------------------------|
It can't be done well with the JAXB we have in 2.0.x, I am told.
Aegis does it nicely. The trunk uses new stuff in JAXB, which supposedly
supports it, but I don't have any experience.
> -----Original Message-----
> From: Kaleb Walton [mailto:kdwalton@us.ibm.com]
> Sent: Wednesday, November 28, 2007 10:14 AM
> To: cxf-user@incubator.apache.org
> Subject: Example of JAXB and HashMap serialization?
>
>
>
> I'm writing documentation for how to write services and got
> to a point where I have to say "Do not use HashMap's in any
> of your services as CXF + JAXB does not support serializing
> HashMaps". I'd rather not have to say that - are there any
> examples out there of how to get HashMaps to serialize using
> CXF + JAXB?
>
> I've seen the XmlAdapter stuff out there but that doesn't
> suit my needs for two reasons:
>
> 1) We don't use annotations
> 2) We want to use HashMaps, not pseudo-maps
>
> I may be misunderstanding the solutions pointed out in the
> articles, if so please help me see the light!
>
> Regards,
> Kaleb
>
RE: Example of JAXB and HashMap serialization?
Posted by Benson Margulies <bi...@basistech.com>.
It can't be done well with the JAXB we have in 2.0.x, I am told.
Aegis does it nicely. The trunk uses new stuff in JAXB, which supposedly
supports it, but I don't have any experience.
> -----Original Message-----
> From: Kaleb Walton [mailto:kdwalton@us.ibm.com]
> Sent: Wednesday, November 28, 2007 10:14 AM
> To: cxf-user@incubator.apache.org
> Subject: Example of JAXB and HashMap serialization?
>
>
>
> I'm writing documentation for how to write services and got
> to a point where I have to say "Do not use HashMap's in any
> of your services as CXF + JAXB does not support serializing
> HashMaps". I'd rather not have to say that - are there any
> examples out there of how to get HashMaps to serialize using
> CXF + JAXB?
>
> I've seen the XmlAdapter stuff out there but that doesn't
> suit my needs for two reasons:
>
> 1) We don't use annotations
> 2) We want to use HashMaps, not pseudo-maps
>
> I may be misunderstanding the solutions pointed out in the
> articles, if so please help me see the light!
>
> Regards,
> Kaleb
>