Duh : Jackson also supports Xml de/serialization

I have always had trouble dealing with XML in Java.  In particular, I'm sure I've (in the past) spent hours struggling with nodes and the API in the DocumentBuilder factories.   Its also never been entirely clear what the "standard" for XML parsing is in Java.

My recent positive experiences with Jackson led me to define my own, new, defacto standard ... Jackson.  That is--- after I realized Jackson supported XML - this was a no brainer.  Because rather than modelling my document - I could simply print it out as a map - and look at the fields which I wanted , decide on the necessary resolution (i.e. is a List okay --- or do I need a bean for this entity?) --- and then serialize away.


Below is the source code for a SOLR xml parser .  This code was obviated very quickly when mister Domen Grabec and I learned that its possible to simply create a SolrCore object by using an AbstractSolrBaseTest object (we have'nt yet found a simple way to create a SolrCore object yet, but I'm sure there is a trick buried somewhere in the API). Nevertheless, this test is functionally identical and requires no inheritance, and no external libraries, and most importantly, demonstrates how easy it is to de/serialize xml objects to validate xml input/output in an application using Jackson.

The purpose of this class is simply to make sure that a SolrIndex creator is creating field names that correspond to the dynamic and/or static field names defined in the Solr xml schema.  It could similarly be used, thus, to validate a hibernate schema .  That is, it could be genericized to validate that any "map-like" data class had fields which corresponded to field names (including regular expressions for names) found in an XML file. 

    //You have to create your own *XMLSchema class.  The easiest way to start with this is to create a class with a few simple fields that map to some of the top level attributes in your XML data.  Jackson will magically take care of the rest with Lists/Maps.

    //This method reads in a solr schema
    public static List<Pattern> fields(String xmlFileName) throws IOException, Exception {

        File pathToSolrSchema = new File(xmlFileName);

        String schema = FileUtils.readFileToString(pathToSolrSchema );

        SolrXMLSchema nodes = new XmlMapper().readValue(schema, MyXMLSchemaBean.class);

        List<Pattern> fieldNames = new ArrayList<Pattern>();

       

        for(Map l : nodes.getFields())

        {

            String fieldPattern = l.get("name").toString();

            fieldPattern=fieldPattern.replaceAll("\\*", ".*");

            fieldPattern = StringEscapeUtils.escapeJava(fieldPattern);

            fieldNames.add(Pattern.compile(fieldPattern) );

        }

        return fieldNames;

    }

Oh by the way -- heres the SolrSchemaBean that I used to test this. 

package net.peerindex.pisae.solr;

import java.util.List;
import java.util.Map;
/**
 * Can be used to manually parse the solr index files.
 * Now not necssary -- now we just use @link{TestHarness}.getCore().
 * @author Jpeerindex
 */
public class SolrXMLSchema {

    public Object getDefaultSearchField() {
        return defaultSearchField;
    }
    public void setDefaultSearchField(Object defaultSearchField) {
        this.defaultSearchField = defaultSearchField;
    }
    Object name,solrQueryParser,types,uniqueKey,version,defaultSearchField;
    List<Map> fields;
    public Object getName() {
        return name;
    }
    public void setName(Object name) {
        this.name = name;
    }
    public Object getSolrQueryParser() {
        return solrQueryParser;
    }
    public void setSolrQueryParser(Object solrQueryParser) {
        this.solrQueryParser = solrQueryParser;
    }
    public Object getTypes() {
        return types;
    }
    public void setTypes(Object types) {
        this.types = types;
    }
    public Object getUniqueKey() {
        return uniqueKey;
    }
    public void setUniqueKey(Object uniqueKey) {
        this.uniqueKey = uniqueKey;
    }
    public Object getVersion() {
        return version;
    }
    public void setVersion(Object version) {
        this.version = version;
    }
    public List<Map> getFields() {
        return fields;
    }
    public void setFields(List<Map> fields) {
        this.fields = fields;
    }
   
}