Java Doc for BindingConfiguration.java in  » GIS » GeoTools-2.4.1 » org » geotools » xml » Java Source Code / Java DocumentationJava Source Code and Java Documentation

Strategy objects live inside a pico container. This provides the strategy with the following:

• Life cycle
• Dependency management

Life Cycle

Dependencies

To achieve IoC, Pico Container uses a mechanism known as Contstructor Injection. In this scheme, a particular component specifies all of its dependencies in its constructor. The container will ensure that the dependencies are satisfied when the component is instantiated. For an more detailed explanation, see Constructor Injection.

So how does the container know which implementation to supply to the component when it is instantiated? An implementation of the dependency must be registered with the container before the component is instantiated. This is usually done at parser configuration time. See org.geotools.xml.Configurationfor more details . Consider the following strategy.

 
 class MyBinding extends SimpleBinding {
 List list;
 public MyBinding(List list) {
 this.list = list;
 }
 public Object parse(InstanceComponent instance, Object value)
 throws Exception {
 list.add(value);
 return list;
 }
 }
 
 

 
 class MyBindingConfiguration implements BindingConfiguration {
 public void configure(MutablePicoContainer container) {
 //first register a concrete implemtnation of list
 container.registerComponentImplementation(LinkedList.class);
 //register the actual component
 QName qName = new QName("http://geotools/org/", "my");
 container.registerComponentImplementation(qName,MyStrategy.class);
 }
 }
 
 

A binding is looked up in the container by its qualified name. The following code snippet illustrates how to register a strategy with the container.

 
 void configure(MutablePicoContainer container) {
 QName qName = FOO.BARTYPE;
 Class impl = F00BarBinding.class;
 container.registerComponentImplementation(qName,impl);
 }