The Java EE 6 Tutorial

Creating a Backing Bean

A backing bean is created with a constructor with no arguments (like all JavaBeans components) and a set of properties and a set of methods that perform functions for a component. Each of the backing bean properties can be bound to one of the following:

The most common functions that backing bean methods perform include the following:

As with all JavaBeans components, a property consists of a private data field and a set of accessor methods, as shown by this code:

Integer userNumber = null;
...
public void setUserNumber(Integer user_number) {
    userNumber = user_number;
}
public Integer getUserNumber() {
    return userNumber;
}
public String getResponse() {
    ...
}

When bound to a component’s value, a bean property can be any of the basic primitive and numeric types or any Java object type for which the application has access to an appropriate converter. For example, a property can be of type Date if the application has access to a converter that can convert the Date type to a String and back again. See Writing Bean Properties for information on which types are accepted by which component tags.

When a bean property is bound to a component instance, the property’s type must be the same as the component object. For example, if a javax.faces.component.UISelectBoolean component is bound to the property, the property must accept and return a UISelectBoolean object. Likewise, if the property is bound to a converter, validator, or listener instance, the property must be of the appropriate converter, validator, or listener type.

For more information on writing beans and their properties, see Writing Bean Properties.