EDIT

/**

 * 

 */

package eu.etaxonomy.taxeditor.ui.section;

import java.util.Collection;

import org.apache.commons.collections.CollectionUtils;

import org.eclipse.jface.action.Action;

import org.eclipse.jface.action.ToolBarManager;

import org.eclipse.jface.resource.ImageDescriptor;

import org.eclipse.swt.SWT;

import org.eclipse.swt.events.SelectionAdapter;

import org.eclipse.swt.events.SelectionEvent;

import org.eclipse.swt.events.SelectionListener;

import org.eclipse.swt.graphics.Color;

import org.eclipse.swt.graphics.ImageData;

import org.eclipse.swt.widgets.Composite;

import org.eclipse.swt.widgets.Control;

import org.eclipse.swt.widgets.Label;

import org.eclipse.ui.forms.events.ExpansionEvent;

import org.eclipse.ui.forms.events.IExpansionListener;

import org.eclipse.ui.forms.widgets.Section;

import eu.etaxonomy.cdm.api.conversation.ConversationHolder;

import eu.etaxonomy.cdm.common.CdmUtils;

import eu.etaxonomy.taxeditor.model.ImageResources;

import eu.etaxonomy.taxeditor.preference.IPreferenceKeys;

import eu.etaxonomy.taxeditor.preference.PreferencesUtil;

import eu.etaxonomy.taxeditor.preference.Resources;

import eu.etaxonomy.taxeditor.store.StoreUtil;

import eu.etaxonomy.taxeditor.ui.forms.AbstractFormSection;

import eu.etaxonomy.taxeditor.ui.forms.CdmFormFactory;

import eu.etaxonomy.taxeditor.ui.forms.ICdmFormElement;

/**

 * <p>Abstract AbstractEntityCollectionSection class.</p>

 *

 * @author n.hoffmann

 * @version $Id: $

 */

public abstract class AbstractEntityCollectionSection<ENTITY, ELEMENT> extends AbstractFormSection<ENTITY> implements IExpansionListener{

	protected Composite container;

	private Label label_empty;

	private String title;

	/**

	 * <p>Constructor for AbstractEntityCollectionSection.</p>

	 *

	 * @param conversation 

	 * @param parentElement a {@link eu.etaxonomy.taxeditor.ui.forms.ICdmFormElement} object.

	 * @param style a int.

	 * @param formFactory a {@link eu.etaxonomy.taxeditor.ui.forms.CdmFormFactory} object.

	 * @param title a {@link java.lang.String} object.

	 * @param <ENTITY> a ENTITY object.

	 * @param <ELEMENT> a ELEMENT object.

	 */

	public AbstractEntityCollectionSection(CdmFormFactory formFactory, ConversationHolder conversation, ICdmFormElement parentElement, String title, int style) {

		super(formFactory, parentElement, Section.CLIENT_INDENT | style);

		this.title = title;

		this.setText(getTitleString());

		showToolbar();

		addExpansionListener(this);

	}

	protected Control createToolbar() {

		ToolBarManager toolBarManager = new ToolBarManager(SWT.FLAT);

		Action addAction = new Action("add", Action.AS_PUSH_BUTTON){

			/* (non-Javadoc)

			 * @see org.eclipse.jface.action.Action#run()

			 */

			@Override

			public void run() {

				ELEMENT element = createNewElement();

				if(element != null){

					addElement(element);

					if(! getSection().isExpanded())

						getSection().setExpanded(true);

					internalUpdateSection(true);

				}

			}

		};

		addAction.setImageDescriptor(new ImageDescriptor() {

			@Override

			public ImageData getImageData() {

				return ImageResources.getImage(ImageResources.ADD_ICON).getImageData();

			}

		});

		addAction.setToolTipText(getTooltipString());

		toolBarManager.add(addAction);

		return toolBarManager.createControl(this);

	}

	public void showToolbar(){

		setTextClient(createToolbar());

	}

	public void removeToolbar(){

		setTextClient(null);

	}

	/**

	 * <p>setEntity</p>

	 *

	 * @param entity a ENTITY object.

	 */

	@Override

	public void setEntity(ENTITY entity) {

		if(entity != null && hasCollectionChanged(entity)){

			super.setEntity(entity);

			internalUpdateSection(false);

		}

		setSectionTitle();

		layout();

	};

	/**

	 * Sets the title for the section. Adds a "+" sign if the collection is not empty for this section.

	 * Override in subclasses if you want to have a different behaviour.

	 */

	protected void setSectionTitle() {

		if(getCollection(getEntity()) != null && getCollection(getEntity()).size() > 0){

			this.setText(getTitleString() + " +");

		}else{

			this.setText(getTitleString());

		}

	}

	/**

	 * Removes all content from the container

	 */

	private void destroyDynamicContent(){

		if(label_empty != null){

			label_empty.dispose();

			label_empty = null;

		}

		removeElements();

	}

	/**

	 * Call this method after dynamically changing the client area.

	 * If the options changed is set to true, will also fire a state changed

	 * event to inform the user of unsaved changes.

	 *

	 * @param changed a boolean.

	 */

	protected void internalUpdateSection(boolean changed){

		destroyDynamicContent();

		if(isExpanded() || expandSectionWhenContentAvailable())

			renderContent(isExpanded());

		if(changed)

			firePropertyChangeEvent(this);

	}

	/**

	 * Whether the entities specific collection changed

	 * 

	 * @param newEntity

	 * @return

	 */

	private boolean hasCollectionChanged(ENTITY newEntity){

		// return true on null

		if(getEntity() == null || newEntity == null)	return true;	

		// if the entities differ the collection has changed

		if(! getEntity().equals(newEntity)) return true;

		Collection<ELEMENT> oldCollection = getCollection(getEntity());

		Collection<ELEMENT> newCollection = getCollection(newEntity);

		// return true on null

		if(oldCollection == null || newCollection == null) return true;

		// if the collections are object equal, check if the content is equal, too

		if(oldCollection.equals(newCollection)){

			boolean equal = CollectionUtils.isEqualCollection(oldCollection, newCollection);

			// return true when collections are not equal

			return equal ? false : true;

		}

		return true;

	}

	/**

	 * Create the elements to be shown in this seciton client area 

	 */

	private void renderContent(boolean forceExpansion)

	{

		Collection<ELEMENT> elements = getCollection(getEntity());

		if(elements == null || elements.isEmpty()){

			createEmptyContent();

		}else{

			createDynamicContents(elements);

			forceExpansion = true;

		}

		this.setExpanded(forceExpansion);

		reflow();

	}

	/**

	 * <p>createEmptyContent</p>

	 */

	protected void createEmptyContent(){

		label_empty = formFactory.createLabel(getLayoutComposite(), getEmptyString());

	}

	/**

	 * Creates the widgets for the collection

	 *

	 * @param elements a {@link java.util.Collection} object.

	 */

	protected void createDynamicContents(Collection<ELEMENT> elements)

	{		

		int i = 0;

		for(final ELEMENT element : elements){

			SelectionAdapter removeListener = new SelectionAdapter(){

				@Override

				public void widgetSelected(SelectionEvent e) {

					removeElement(element);					

					internalUpdateSection(true);

				}

			};

			boolean modulo = i++%2 == 0;

			String colorResource = modulo ? Resources.COLOR_LIST_EVEN : Resources.COLOR_LIST_ODD;

			createElementComposite(element, removeListener, StoreUtil.getColor(colorResource));

		}

	}

	/**

	 * Create the specific widget for the element

	 *

	 * @param element a ELEMENT object.

	 * @param removeListener a {@link org.eclipse.swt.events.SelectionListener} object.

	 * @param backgroundColor a {@link org.eclipse.swt.graphics.Color} object.

	 */

	protected void createElementComposite(ELEMENT element, SelectionListener removeListener, Color backgroundColor){

		AbstractEntityCollectionElement formElement = formFactory.createEntityCollectionElement(this, element, removeListener, backgroundColor, SWT.NULL);

	}

	/* (non-Javadoc)

	 * @see eu.etaxonomy.taxeditor.forms.section.AbstractEditorFormSection#setBackground(org.eclipse.swt.graphics.Color)

	 */

	/** {@inheritDoc} */

	@Override

	public void setBackground(Color color) {

		if(label_empty != null && !label_empty.isDisposed()){

			label_empty.setBackground(color);

		}

		super.setBackground(color);

	}

	/**

	 * <p>getTitleString</p>

	 *

	 * @return a {@link java.lang.String} object.

	 */

	public String getTitleString() {

		return CdmUtils.Nz(title);

	}

	/**

	 * <p>setTitleString</p>

	 *

	 * @param title a {@link java.lang.String} object.

	 */

	public void setTitleString(String title){

		this.title = title;

		setSectionTitle();

		layout();

	}

	/** {@inheritDoc} */

	public void expansionStateChanging(ExpansionEvent e) {

//		logger.warn("Expansion State Changing");

	}

	/** {@inheritDoc} */

	public void expansionStateChanged(ExpansionEvent e) {

		if(isExpanded()){

			renderContent(isExpanded());

		}else{

			destroyDynamicContent();

		}

	}

	private boolean expandSectionWhenContentAvailable(){

		return PreferencesUtil.getPreferenceStore().getBoolean(IPreferenceKeys.SHOULD_EXPAND_SECTION_WHEN_DATA_AVAILABLE);

	}

	/**

	 * Get the specific collection of this entity

	 *

	 * @param entity a ENTITY object.

	 * @return a {@link java.util.Collection} object.

	 */

	public abstract Collection<ELEMENT> getCollection(ENTITY entity);

	/**

	 * Create a new Element for this collection

	 *

	 * @return a ELEMENT object.

	 */

	public abstract ELEMENT createNewElement();

	/**

	 * Add an element to the entities collection

	 *

	 * @param element a ELEMENT object.

	 */

	public abstract void addElement(ELEMENT element);

	/**

	 * Remove an element from the entities collection

	 *

	 * @param element a ELEMENT object.

	 */

	public abstract void removeElement(ELEMENT element);

	/**

	 * String to display when the collection is empty

	 *

	 * @return a {@link java.lang.String} object.

	 */

	public abstract String getEmptyString();

	/**

	 * <p>getTooltipString</p>

	 *

	 * @return String to display when hovering the add button

	 */

	protected abstract String getTooltipString();	

}