bpel-nobj/src/main/java/org/apache/ode/bpel/obj/ExtensibleImpl.java

package org.apache.ode.bpel.obj;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.LinkedHashMap;
import java.util.Map;

import org.apache.ode.bpel.obj.serde.jacksonhack.UniqueStringIdGenerator;

import com.fasterxml.jackson.annotation.JsonIdentityInfo;
import com.fasterxml.jackson.annotation.JsonIgnore;

@JsonIdentityInfo(generator = UniqueStringIdGenerator.class, property = "@id")
public class ExtensibleImpl  implements Extensible<Object>, Serializable{
	public static final long serialVersionUID = -1L;
	public static final int CURRENT_CLASS_VERSION = 1;
	
	/** The wrapper wraps fields. Fields can be deleted, added or updated */
	transient protected Map<String, Object> fieldContainer;
	/** Version of this class*/
	private static final String CLASSVERSION = "classVersion";
	/** Original version before migration*/
	private static final String ORIGINALVERSION = "originalVersion";

	protected ExtensibleImpl() {
		this(new LinkedHashMap<String, Object>());
	}
	protected ExtensibleImpl(Map<String, Object> container) {
		fieldContainer = container;
		int currentVersion = 0;
		try {
			currentVersion = (Integer) this.getClass().getField("CURRENT_CLASS_VERSION").get(this);
		} catch (Exception e) {
			// should never get here
			e.printStackTrace();
		}
		setClassVersion(currentVersion);
		setOriginalVersion(currentVersion); //if this is called by deserializer, original will be set later.
	}
	
//	@JsonAnyGetter
	public Map<String, Object> getFieldContainer() {
		return fieldContainer;
	}
	public void setFieldContainer(Map<String, Object> fieldContainer){
		this.fieldContainer = fieldContainer;
	}

//	@JsonAnySetter
	public void addField(String name, Object value) {
		fieldContainer.put(name, value);
	}

	public Object getField(String name) {
		return fieldContainer.get(name);
	}

	@Override
	public Object delField(String fieldName) {
		return fieldContainer.remove(fieldName);
	}
	
	@JsonIgnore
	public int getClassVersion() {
		Object o = fieldContainer.get(CLASSVERSION);
		return o == null ? 0 : (Integer)o;
	}

	public void setClassVersion(int version) {
		fieldContainer.put(CLASSVERSION, version);
	}
	
	@JsonIgnore
	public int getOriginalVersion(){
		Object o = fieldContainer.get(ORIGINALVERSION);
		return o == null? -1 : (Integer)o;
	}
	public void setOriginalVersion(int version){
		fieldContainer.put(ORIGINALVERSION, version);
	}
	
	private void writeObject(ObjectOutputStream oos) throws IOException{
		oos.defaultWriteObject();
		oos.writeInt(fieldContainer.size());
		oos.writeObject(fieldContainer.getClass().getName());
		for (String key : fieldContainer.keySet()){
			oos.writeObject(key);
			oos.writeObject(fieldContainer.get(key));
		}
	}
	private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException{
		ois.defaultReadObject();
		int size = ois.readInt();
		String cls = (String)ois.readObject();
		try {
			fieldContainer = (Map<String, Object>)(Class.forName(cls).newInstance());
		} catch (Exception e) {
			//should never get here
			e.printStackTrace();
		}
		for (int i = 0; i < size; i++){
			String key = (String)ois.readObject();
			Object value = ois.readObject();
			fieldContainer.put(key, value);
		}
	}
	
	@Override
	public void upgrade2Newest(){
		int version = getClassVersion();
		int currentVersion = version;
		try {
			currentVersion = (Integer) this.getClass().getField("CURRENT_CLASS_VERSION").get(this);
		} catch (Exception e) {
			// should never get here
			e.printStackTrace();
		}
		if (version == currentVersion) return;
		if (version > currentVersion){
			//should never get here. 
			throw new RuntimeException("class version is newer than newest!");
		}
		setClassVersion(currentVersion);
		return;
	}
}