JOT Servlets - Programmers Guide

Programmers Guide > JOT Beans

JOT Beans

JOT Bean Properties:

JOT Template tokens obtain dynamic content from the properties of Java objects, including J2EE and POJO classes (plain old java objects). The framework includes JotBean base classes that applications can extend (see Extending JOT Beans). Non JotBeans are transparently enveloped with the getInstance() JotBean wrapper method.

Examples:

In the following example, the JOT.Foo token refers to the foo property using the method getFoo(). Token JOT.Foo(bar) invokes getFoo() with argument bar.

    JOT Template: JOT.Foo and JOT.Foo(bar)

    JOT Bean: public String getFoo()
    JOT Bean: public String getFoo(String arg)

In the next example, property fooBarA uses two parameters.

    JOT Template: JOT.FooBarA(literal1, literal2)

    JOT Bean: public String getFooBarA(String arg1, String arg2)

Property fooBarB in the next example uses the dynamic value of property fooBarC as a parameter.

    JOT Template: JOT.FoobarB(bar1, JOT.FoobarC(bar2), bar3)

    JOT Bean: public String getFoobarB(String b1, Object b2, String b3)
    JOT Bean: public String getFoobarC(String b)

List parameters using the "[]" operator are Object array arguments.

    JOT Template: JOT.Vacations([JOT.Christmas, JOT.Ramadan, JOT.NewYears])

    JOT Bean: public String getVacations(Object[] dates)

Assigning Values to Properties:

A JOT Template uses assignment tokens to set property values with the '=' operator. The next example invokes the setFoobarD() setter method with two arguments.

    JOT Template: JOT.FoobarD=(literal1, JOT.FoobarC(bar2))

    JOT Bean: public String setFoobarD(String arg1, Object arg2)

If there is no matching setter method then the assignment token creates a property with the given value. The next example sets the Title property on the ShoppingCart object.

    JOT Template: JOT.ShoppingCart.Title=(Shopping Cart for JOT.CustomerName)

JotServletBeans:

JOT Beans that implement the JotServletBean interface (including JOT Web Components) have access to JSP Page scope attributes, Request parameters, and Request, Session, and Application attributes as automatic properties.

Indirect Properties:

JOT Template tokens can reference indirect properties. The following example accesses dynamic content from the bar property of the batz property of the foo object.

    JOT.foo.batz.bar(a, b)

The next example returns the CustomerID attribute property of the built-in session object.

    JOT.Session.Attribute(CustomerID)

Since Session attributes are automatic properties, the previous example could also be written as:

    JOT.CustomerID

Implementing JOT Bean Properties:

A JotBean property is typically a getter method that returns a String for the rendering engine. Property values can also be JotBean components or any other type of object. In the following example, the numeric Price property is implemented with a getPrice() method:

    JOT Template: JOT.Price

    public Double getPrice()
    {
        return getProduct().getPrice();
    }

Properties can be declared on a JOT Template and created and initialized automatically by the framework (see Declaring JOT Beans). However, if a property is not created that way, and is itself a JotBean, it must be prepared and registered with the current JotServletServiceContext, as in this example that renders the Price property of an Inventory JotBean:

    JOT Template: JOT.Product.Price

    public Product getProduct()
    {
        return serviceContext.prepareJotBean(new Inventory(selectedProductID));
    }

A property can also be added to a JotBean dynamically. The following example uses addJotBeanProperty() to create and initialize a property named "SelectedProduct":

    JOT Template: JOT.SelectedProduct.Price
 
    public void prepareJotBean()
        throws JotException
    {
        super.prepareJotBean();
        addJotBeanProperty("SelectedProduct", new Inventory(selectedProductID));
    }