GenericObjectManager.java

package com.t3.xstreamversioned.model;

import java.util.HashMap;

import org.apache.commons.lang3.StringUtils;

import com.t3.xstreamversioned.version.Version;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;

public class GenericObjectManager {
		
	private HashMap<Integer, GenericObject> parsedObjects=new HashMap<>();
	private int nextId=0;
	private int nextNegativeId=-1;
	
	public GenericObject parse(HierarchicalStreamReader reader, UnmarshallingContext context) {
		int internalId=reader.getAttribute("id")==null?nextNegativeId--:Integer.parseInt(reader.getAttribute("id"));
		
		GenericObject go=new GenericObject(this,internalId);
		parsedObjects.put(internalId, go);
		nextId=Math.max(internalId+1, nextId);
		
		go.setName(reader.getNodeName());
		
		//collect all attributes to ensure compatibility
		HashMap<String, String> xStreamAttributes=new HashMap<String, String>();
		for(int i=0;i<reader.getAttributeCount();i++) {
			String attrName=reader.getAttributeName(i);
			if(!"version".equals(attrName))
				xStreamAttributes.put(attrName, reader.getAttribute(i));
		}
		go.setXStreamAttributes(xStreamAttributes);
		
		//version
		String version=reader.getAttribute("version");
		if(version!=null) go.setCurrentVersion(Version.parseVersion(version));
		
		
		//reference
		String referencedId=reader.getAttribute("reference");
		if(referencedId!=null) {
			GenericObject ref=parsedObjects.get(Integer.parseInt(referencedId));
			if(ref==null)
				throw new RuntimeException("Reference to object "+referencedId+" before it occured directly");
			else
				go.setReferencing(ref);
		}
		
		
		//child elements or content
		if(reader.hasMoreChildren()) {
			while(reader.hasMoreChildren()) {
				reader.moveDown();
				go.addChild(parse(reader, null));
				reader.moveUp();
			}
		}
		else
			go.setContent(reader.getValue());
		return go;
	}

	public GenericObject getObject(Integer childId) {
		GenericObject go=parsedObjects.get(childId);
		if(go==null)
			throw new IllegalArgumentException("No Object of id "+childId+" was parsed.");
		else
			return go;
	}
	
	public GenericObject createObject() {
		GenericObject go= new GenericObject(this, nextId++);
		parsedObjects.put(go.getInternalId(), go);
		return go;
	}

	public void updateObject(GenericObject go) {
		parsedObjects.put(go.getInternalId(), go);
	}
}