/*******************************************************************************
 *  Copyright (c) 2010 Association for Decentralized Information Management in
 *  Industry THTH ry.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  Contributors:
 *      VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.databoard.accessor.binary;

import java.io.IOException;

import org.simantics.databoard.Bindings;
import org.simantics.databoard.accessor.Accessor;
import org.simantics.databoard.accessor.FloatAccessor;
import org.simantics.databoard.accessor.error.AccessorConstructionException;
import org.simantics.databoard.accessor.error.AccessorException;
import org.simantics.databoard.accessor.error.ReferenceException;
import org.simantics.databoard.accessor.event.Event;
import org.simantics.databoard.accessor.event.ValueAssigned;
import org.simantics.databoard.accessor.file.FileFloatAccessor;
import org.simantics.databoard.accessor.impl.AccessorParams;
import org.simantics.databoard.accessor.impl.ListenerEntry;
import org.simantics.databoard.accessor.interestset.FloatInterestSet;
import org.simantics.databoard.accessor.reference.ChildReference;
import org.simantics.databoard.binding.Binding;
import org.simantics.databoard.binding.FloatBinding;
import org.simantics.databoard.binding.error.BindingException;
import org.simantics.databoard.type.FloatType;
import org.simantics.databoard.util.binary.Blob;

public class BinaryFloat extends BinaryObject implements FloatAccessor, FileFloatAccessor {

	public BinaryFloat(BinaryObject parent, Blob blob, FloatType type, AccessorParams params) 
	throws AccessorConstructionException {
		super(parent, blob, type, params);
		try {
			blob.setLength(4L);
		} catch (IOException e) {
			throw new AccessorConstructionException(e);
		}
	}

	@Override
	public FloatType type() {
		return (FloatType) type;
	}

	@Override
	public float getValue() throws AccessorException {
		assert b.isOpen();
		readLock();
		try {
			b.position(0L);
			return b.readFloat();
		} catch (IOException e) {
			throw new AccessorException(e);
		} finally {
			readUnlock();
		}
	}

	@Override
	Event applyLocal(Event e, boolean makeRollback) throws AccessorException {
		Event rollback = makeRollback ? new ValueAssigned( Bindings.FLOAT, getValue() ) : null; 		
		if (e instanceof ValueAssigned) {
			ValueAssigned va = (ValueAssigned) e;
			if (va.newValue == null) throw new AccessorException("Float value expected, got null");
			setValueNoflush(va.newValue.getBinding(), va.newValue.getValue());
			return rollback;
		} else {
			throw new AccessorException("Cannot apply "+e.getClass().getName()+" to Float");
		}
	}

	@SuppressWarnings("unchecked")
	@Override
	public <T extends Accessor> T getComponent(ChildReference reference)
			throws AccessorConstructionException {
		if (reference==null) return (T) this;		
		throw new ReferenceException(reference.getClass()+" is not a subreference of FloatType");	
	}

	@Override
	public Object getValue(Binding binding) throws AccessorException {
		assert b.isOpen();
		readLock();
		try {
			FloatBinding bb = (FloatBinding) binding; 
			float v = getValue();
			return bb.create(v);
		} catch(BindingException e) {		
			throw new AccessorException(e);
		} finally {
			readUnlock();
		}
	}

	public void setValueNoflush(float newValue) throws AccessorException {
		assert b.isOpen();
		writeLock();
		try {
			// Set value
			b.position(0);			
			b.writeFloat( newValue );
			
			// Notify
			ListenerEntry le = listeners;
			while (le!=null) {
				FloatInterestSet is = le.getInterestSet();
				if (is.inNotifications()) {					
					Event e = new ValueAssigned( Bindings.FLOAT, is.inValues() ? newValue : null );
					emitEvent(le, e);
				}
				le = le.next;
			}
			
		} catch (IOException e) {
			throw new AccessorException(e);
		} finally {
			writeUnlock();
		}
	} 
	
	@Override
	public void setValue(float newValue) throws AccessorException {
		assert b.isOpen();
		writeLock();
		try {
			setValueNoflush(newValue);
			b.flush();
		} catch (IOException e) {
			throw new AccessorException(e);
		} finally {
			writeUnlock();
		}
	}
	
	@Override
	public void setValueNoflush(Binding binding, Object newValue)
			throws AccessorException {
		try {
			float nv = ((FloatBinding)binding).getValue_(newValue);
			setValueNoflush(nv);
		} catch (BindingException e) {
			throw new AccessorException(e);
		}
	}
	
}