/*
 * JBoss, Home of Professional Open Source.
 *
 * See the LEGAL.txt file distributed with this work for information regarding copyright ownership and licensing.
 *
 * See the AUTHORS.txt file distributed with this work for a full listing of individual contributors.
 */
package org.teiid.query.ui.builder.model;

import org.teiid.designer.query.sql.lang.ILanguageObject;

/**
 * The <code>ILanguageObjectEditorModel</code> interface represents a model of an
 * ILanguageObjectEditor's state. It holds a saved value and a current
 * value.
 *
 * @since 8.0
 */
public interface ILanguageObjectEditorModel {
    
    /**
     * Adds the given listener to the listeners receiving model change notifications. If the listener is
     * already registered, they are not added again.
     * @param theListener the listener being added
     * @return <code>true</code> if the listener was added; <code>false</code> otherwise.
     * @throws IllegalArgumentException if listener is <code>null</code>
     */
    boolean addModelListener(ILanguageObjectEditorModelListener theListener);

    /**
     * Clears the model causing it to be placed in it's initial state with no saved <code>LanguageObject</code>.
     */
    void clear();
    
    /**
     * Gets the model's current <code>LanguageObject</code>. May not be equal to it's last saved value.
     * @return the language object or <code>null</code> if not complete and valid
     */
    ILanguageObject getLanguageObject();
    
    /**
     * Gets the <code>LanguageObject</code> class associated with this model.
     * @return the type
     */
    Class getModelType();
    
    /**
     * Indicates if the current <code>LanguageObject</code> is different from the saved value.
     * @return <code>true</code> if different; <code>false</code> otherwise.
     */
    boolean hasChanged();
    
    /**
     * Indicates if the current <code>LanguageObject</code> is complete.
     * @return <code>true</code> if complete; <code>false</code> when incomplete.
     */
    boolean isComplete();
    
    /**
     * Removes the given listener from the listeners receiving model change notifications.
     * @param theListener the listener being removed
     * @return <code>true</code> if the listener was removed; <code>false</code> otherwise.
     * @throws IllegalArgumentException if listener is <code>null</code>
     */
    boolean removeModelListener(ILanguageObjectEditorModelListener theListener);
    
    /**
     * Sets the model's current value equal to it's last saved <code>LanguageObject</code> or null.
     */
    void reset();
    
    /**
     * Saves the current <code>LanguageObject</code>.
     * @throws IllegalStateException if current value is not complete
     */
    void save();
    
    /**
     * Sets the model's saved <code>LanguageObject</code> and it's current <code>LanguageObject</code>.
     * @param theLanguageObject the value being used
     * @throws IllegalArgumentException if the object is not of the proper type
     */
    void setLanguageObject(ILanguageObject theLangObj);
    
    /**
     * Gets the <code>LanguageObject</code> class associated with this model.
     * @param the theLanguageObjectClass the type
     */
    void setModelType(Class theLanguageObjectClass);
    
}