package org.simantics.databoard.binding.mutable;

import org.simantics.databoard.binding.Binding;
import org.simantics.databoard.binding.UnionBinding;
import org.simantics.databoard.binding.error.BindingException;
import org.simantics.databoard.type.UnionType;

/**
 * Binds UnionType to TaggedObject.class
 *
 * @author Toni Kalajainen <toni.kalajainen@vtt.fi>
 */
public class UnionTaggedObjectBinding extends UnionBinding {

	public UnionTaggedObjectBinding(UnionType type, Binding[] componentBindings)
	{
		this.componentBindings = componentBindings;
        if (type==null) throw new IllegalArgumentException("null arg");
		this.type = type;
	}

	@Override
	public Object create(int tag, Object value) {
		TaggedObject result = new TaggedObject();
		result.tag = tag;
		result.value = value;
		return result;
	}
	
	@Override
	public void setValue(Object union, int tag, Object value)
	throws BindingException {
		TaggedObject result = (TaggedObject)union;
		result.tag = tag;
		result.value = value;
	}

	@Override
	public int getTag(Object obj) throws BindingException {
		if (!isInstance(obj)) throw new BindingException("Unexpected class "+obj.getClass().getSimpleName()+", TaggedObject expected");
		TaggedObject to = (TaggedObject) obj;
		return to.tag;
	}

	@Override
	public Object getValue(Object obj) throws BindingException {
		if (!isInstance(obj)) throw new BindingException("Unexpected class "+obj.getClass().getSimpleName()+", TaggedObject expected");
		TaggedObject to = (TaggedObject) obj;
		return to.value;
	}

	@Override
	public boolean isInstance(Object obj) {
		return obj instanceof TaggedObject;
	}
	
}