Recursive traversal finder for children Components. Filling the "traversing utility gap" what too much usage of http://api.jquery.com/category/Traversing/ has caused. Vaadin fundamental traversing consists of Component.getParent(), HasComponents.iterator() and AbstractComponent.findAncestor(Class<T> parentType) . And there should be also HasComp…

VaadinChildrenTraverse.java

	/**
	 * A Vaadin helper utility for getting children of Component By.type
	 * 
	 * @param rootComponent - component where to start
	 * @param criteriaType
	 * @return List of components that match type
	 */
	public static List<Component> getChildrenByClass(HasComponents rootComponent, final Class<?> criteriaType ) {
		return getChildren(rootComponent,By.type(criteriaType));
	}
	
	/**
	 * A Vaadin helper utility for getting children of Component By.type
	 * 
	 * @param rootComponent - component where to start
	 * @param idOfComponent
	 * @return List of components that match type
	 */
	public static List<Component> getChildrenByIdString(HasComponents rootComponent, final String idOfComponent ) {
		return getChildren(rootComponent,By.id(idOfComponent));
	}
	
	/**
	 * A Vaadin helper utility for getting children of Component By.type
	 * 
	 * @param rootComponent - component where to start
	 * @param idString
	 * @return List of components that match type
	 */
	public static List<Component> getChildrenByPartialIdString(HasComponents rootComponent, final String idString ) {
		return getChildren(rootComponent,By.containingIdString(idString));
	}
	
	protected static List<Component> getChildren(HasComponents rootComponent, ComponentMatcher componentMatcher ) {
		List<Component> foundChildrenComponents = new ArrayList<Component>();
		getChildren(rootComponent.iterator(),componentMatcher,foundChildrenComponents);
		return foundChildrenComponents;
	}
	
	/* A bit similar to Selenium2 / WebDriver By selectors */
    public static class By {
    	public static ComponentMatcher id(final String id) {
    		return new ComponentMatcher() {
				@Override
				public boolean doesItMatch(Component component) {
					if(component.getId().equals(id)) {
						return true;
					}
					return false;
				}
			};
    	}
    	public static ComponentMatcher containingIdString(final String idString) {
    		return new ComponentMatcher() {
				@Override
				public boolean doesItMatch(Component component) {
					if(component.getId().contains(idString)) {
						return true;
					}
					return false;
				}
			};
    	}
    	public static ComponentMatcher type(final Class<?> type) {
    		return new ComponentMatcher() {
				@Override
				public boolean doesItMatch(Component component) {
					if(type.isAssignableFrom(component.getClass())) {
						return true;
					}
					return false;
				}
			};
    	}
    }
    
    public static interface ComponentMatcher {
    	boolean doesItMatch(Component component);
    }
	
	protected static void getChildren(Iterator<Component> componentIterator, ComponentMatcher matcher, List<Component> children ) {
		if(!componentIterator.hasNext()) {
			return;
		}
		else {
			Component component = componentIterator.next();
			if(HasComponents.class.isAssignableFrom(component.getClass())) {
				HasComponents hasComponents = (HasComponents) component;
				getChildren(hasComponents.iterator(),matcher,children);
			}
			if( matcher.doesItMatch(component) ) {
				//match found
				children.add(component);
			}
			getChildren(componentIterator,matcher,children);
		}
	}