CrudForm.java

package enterpriseapp.ui.crud;

import javax.persistence.GeneratedValue;
import javax.persistence.OneToMany;

import com.vaadin.data.Item;
import com.vaadin.data.util.BeanItem;
import com.vaadin.ui.Alignment;
import com.vaadin.ui.Button;
import com.vaadin.ui.Field;
import com.vaadin.ui.Form;
import com.vaadin.ui.FormFieldFactory;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;

import enterpriseapp.Utils;
import enterpriseapp.ui.Constants;

/**
 * A CRUD form used by CrudComponent.
 * 
 * @author Alejandro Duarte.
 *
 * @param <T> CRUD Entity class.
 */
public class CrudForm<T> extends Form implements FieldContainer {
		
	private static final long serialVersionUID = 1L;
	
	protected Class<T> type;
	protected boolean autogeneratedId;
	protected boolean hideNewButton;
	protected boolean hideUpdateButton;
	protected boolean hideDeleteButton;
	protected Button newButton = new Button(Constants.uiNew);
	protected Button updateButton = new Button(Constants.uiModify);
	protected Button deleteButton = new Button(Constants.uiDelete);
	protected Button saveButton = new Button(Constants.uiSave);
	protected Button cancelButton = new Button(Constants.uiCancel);
	protected Button firstButton = new Button(Constants.uiFirst);
	protected Button previousButton = new Button(Constants.uiPrevious);
	protected Button nextButton = new Button(Constants.uiNext);
	protected Button lastButton = new Button(Constants.uiLast);

	/**
	 * @param type Entity class.
	 * @param formFieldFactory FormFieldFactory used to create the fields..
	 */
	public CrudForm(Class<T> type, FormFieldFactory formFieldFactory) {
		super();
		this.type = type;
		
		hideNewButton = false;
		hideUpdateButton = false;
		hideDeleteButton = false;
		
		try {
			autogeneratedId = type.getDeclaredField("id").getAnnotation(GeneratedValue.class) != null;
			
		} catch (SecurityException e) {
			throw new RuntimeException(e);
		} catch (NoSuchFieldException e) {
			throw new RuntimeException(e);
		}
		
		setFormFieldFactory(formFieldFactory);
		setBuffered(false);
		setImmediate(true);
		
		initLayout();
		setReadOnly(true);
	}

	/**
	 * Inits the layout. Adds a footer with the CRUD action buttons.
	 */
	public void initLayout() {
		
		HorizontalLayout footer = new HorizontalLayout();
		footer.setSpacing(true);
		footer.setWidth("100%");
		
		Label leftSpacer = new Label();
		leftSpacer.setWidth("100%");
		
		footer.addComponent(leftSpacer);
		footer.setExpandRatio(leftSpacer, 1);
		
		footer.addComponent(newButton);
		footer.addComponent(updateButton);
		footer.addComponent(deleteButton);
		footer.addComponent(saveButton);
		footer.addComponent(cancelButton);
		
		footer.setComponentAlignment(newButton, Alignment.BOTTOM_RIGHT);
		footer.setComponentAlignment(updateButton, Alignment.BOTTOM_RIGHT);
		footer.setComponentAlignment(deleteButton, Alignment.BOTTOM_RIGHT);
		footer.setComponentAlignment(saveButton, Alignment.BOTTOM_RIGHT);
		footer.setComponentAlignment(cancelButton, Alignment.BOTTOM_RIGHT);
		
		setFooter(footer);
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public BeanItem<T> getItemDataSource() {
		return (BeanItem<T>) super.getItemDataSource();
	}
	
	@Override
	public void setItemDataSource(Item newDataSource) {
		setComponentError(null);
		super.setItemDataSource(newDataSource);
		setReadOnly(true);
	}
	
    @Override
    public void setReadOnly(boolean readOnly) {
    	if(getItemDataSource() != null) {
    		for(Object propertyId : getItemDataSource().getItemPropertyIds()) {
    			Field field = getField(propertyId);
    			
    			if(field != null) {
    				configureField(field, propertyId);
    			}
    		}
    		
    		Object[] visibleFieldsFromConfig = Utils.getVisibleFormProperties(type);
    		
    		if(visibleFieldsFromConfig != null) {
    			setVisibleItemProperties(visibleFieldsFromConfig);
    		}
    	}
    	
		newButton.setVisible(readOnly && !hideNewButton);
		updateButton.setVisible(readOnly && getItemDataSource() != null && !hideUpdateButton);
		deleteButton.setVisible(readOnly && getItemDataSource() != null && !hideDeleteButton);
		saveButton.setVisible(!readOnly);
		cancelButton.setVisible(!readOnly);
		
		super.setReadOnly(readOnly);
		Field idField = getField("id");
		
		if(idField != null) {
			if(autogeneratedId || idField.getValue() != null) {
				idField.setReadOnly(true);
			}
		}
		
		if(!readOnly && getItemDataSource() != null) {
			focus();
		}
    }
    
    /**
     * Configures the field when the Form becomes editable (setReadOnly(false)).
     * @param field Field to configure.
     * @param propertyId propertyId, usually String with the property name.
     */
    public void configureField(Field field, Object propertyId) {
		try {
			OneToMany oneToManyAnnotation = type.getDeclaredField(propertyId.toString()).getAnnotation(OneToMany.class);
			
			if(oneToManyAnnotation != null && !oneToManyAnnotation.mappedBy().isEmpty()) {
				field.setReadOnly(true);
				field.setVisible(false);
			}
			
		} catch (SecurityException e) {
			throw new RuntimeException(e);
		} catch (NoSuchFieldException e) {
			throw new RuntimeException(e);
		}
    }

	@Override
	public void addField(Field field, Object propertyId, Item item) {
		super.addField(propertyId, field);
	}

	@Override
	public Field getField(Object propertyId, Item item) {
		return super.getField(propertyId);
	}

	/**
	 * @return true if the ID property is autogenerated.
	 */
	public boolean isAutogeneratedId() {
		return autogeneratedId;
	}
	
	/**
	 * Hides "new" button.
	 */
	public void hideNewButton() {
		newButton.setEnabled(false);
		newButton.setVisible(false);
		hideNewButton = true;
	}
	
	/**
	 * Hides "update" button.
	 */
	public void hideUpdateButton() {
		updateButton.setEnabled(false);
		updateButton.setVisible(false);
		hideUpdateButton = true;
	}
	
	/**
	 * Hides "delete" button.
	 */
	public void hideDeleteButton() {
		deleteButton.setEnabled(false);
		deleteButton.setVisible(false);
		hideDeleteButton = true;
	}
	
}