Permit XmlNamespaceDictionary to serialize XmlHttpContent without a default namespace.

[GoogleCodeExporter]

Version of google-http-java-client (e.g. 1.15.0-rc)?

  1.16.0-rc

Java environment (e.g. Java 6, Android 2.3, App Engine)?

  Java 7

Describe the problem.

Executing the main method of the following class gives a:

  java.lang.IllegalArgumentException: unrecognized alias: (default)

(see below for relevant bits of stacktrace)

public class HttpClientNoNamespace {

    private static class Foo {
        @Key String bar;
    }

    public static void main(String[] args) throws IOException {

        Foo foo = new Foo();
        foo.bar = "test";

        final HttpTransport trans = new NetHttpTransport();
        final HttpRequestFactory fact = trans.createRequestFactory();
        final XmlNamespaceDictionary namespaceDictionary = new XmlNamespaceDictionary();
        final GenericUrl url = new GenericUrl("http://example.com/rest/api");

        fact.buildPutRequest(url, new XmlHttpContent(namespaceDictionary, "Foo", foo)).execute();

    }
}

Exception in thread "main" java.lang.IllegalArgumentException: unrecognized 
alias: (default)
    at com.google.api.client.repackaged.com.google.common.base.Preconditions.checkArgument(Preconditions.java:119)
    at com.google.api.client.util.Preconditions.checkArgument(Preconditions.java:69)
    at com.google.api.client.xml.XmlNamespaceDictionary.getNamespaceUriForAliasHandlingUnknown(XmlNamespaceDictionary.java:296)
    at com.google.api.client.xml.XmlNamespaceDictionary.startDoc(XmlNamespaceDictionary.java:243)
    at com.google.api.client.xml.XmlNamespaceDictionary.serialize(XmlNamespaceDictionary.java:229)
    at com.google.api.client.xml.XmlNamespaceDictionary.serialize(XmlNamespaceDictionary.java:208)
    at com.google.api.client.http.xml.XmlHttpContent.writeTo(XmlHttpContent.java:78)
    at com.google.api.client.http.xml.AbstractXmlHttpContent.writeTo(AbstractXmlHttpContent.java:58)

How would you expect it to be fixed?

Well, I don't *want* to provide a namespace.  The REST service I'm calling 
simply spits the dummy if there are any namespace shenanigans in the root 
element of the request entity.   Various combinations of:

        namespaceDictionary.set("","");
        namespaceDictionary.set(null,"");
        namespaceDictionary.set("", null);
        namespaceDictionary.set(null, null);

don't seem to help me get anywhere.

Either I need more control over how namespaces are treated, or some 
factory-level control over the Serializer which an XmlHttpContent passes to 
NamespaceDictionary.  I don't want to have to extend AbstractHttpContent just 
so that I can effectively override AbstractXmlHttpContent#writeTo(OutputStream) 
and call writeTo(Serializer) with my own Serializer.

Hope that's clear.  Am happy to provide more info.

Original issue reported on code.google.com by david.bu...@machaira.com.au on 5 Sep 2013 at 4:00