package net.sourceforge.fenixedu.util.domain;

import java.lang.reflect.InvocationTargetException;
import java.util.Collection;

import net.sourceforge.fenixedu.domain.exceptions.DomainException;

import org.apache.commons.beanutils.PropertyUtils;

/**
 * Allows to obtain the elements being ordered and the order for each element
 * through reflection by given the name of the slots containing each information
 * required.
 * 
 * @author cfgi
 */
public class SlotSelector<HolderType, ObjectType> implements OrdinalAccessor<HolderType, ObjectType> {
    private String relationName;
    private String slotName;

    public SlotSelector(String relationName, String slotName) {
	super();

	this.relationName = relationName;
	this.slotName = slotName;
    }

    public Collection<ObjectType> getObjects(HolderType holder) {
	try {
	    return (Collection<ObjectType>) PropertyUtils.getProperty(holder, this.relationName);
	} catch (IllegalAccessException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot.access", e);
	} catch (InvocationTargetException e) {
	    throw handleInvocationTargetException(e, "adapter.ordered.relation.invocation.exception");
	} catch (NoSuchMethodException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot", e);
	}
    }

    private RuntimeException handleInvocationTargetException(InvocationTargetException e, String message) {
	if (e.getCause() instanceof RuntimeException) {
	    return (RuntimeException) e.getCause();
	} else {
	    return new DomainException(message, e.getCause());
	}
    }

    public Integer getOrder(ObjectType target) {
	try {
	    return (Integer) PropertyUtils.getProperty(target, this.slotName);
	} catch (IllegalAccessException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot.access", e);
	} catch (InvocationTargetException e) {
	    throw handleInvocationTargetException(e, "adapter.ordered.relation.invocation.exception");
	} catch (NoSuchMethodException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot", e);
	}
    }

    public void setOrder(ObjectType target, Integer order) {
	try {
	    PropertyUtils.setProperty(target, this.slotName, order);
	} catch (IllegalAccessException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot.access", e);
	} catch (InvocationTargetException e) {
	    throw handleInvocationTargetException(e, "adapter.ordered.relation.invocation.exception");
	} catch (NoSuchMethodException e) {
	    throw new DomainException("adapter.ordered.relation.no.slot", e);
	}
    }

}