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Trail: Java Naming and Directory Interface(TM).
Lesson: Naming and Directory Operations
Naming and Directory Operations
Naming Exceptions
Lookup an Object
List the Context
Add, Replace or Remove a Binding
Rename
Create and Destroy Subcontexts
Attribute Names
Read Attributes
Modify Attributes
Add, Replace Bindings with Attributes
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Home Page > Java Naming and Directory Interface(TM). > Naming and Directory Operations
Add, Replace Bindings with Attributes

> The naming examples discussed how you can use `bind()`, `rebind()`, The `DirContext` interface contains overloaded versions of these methods that accept attributes. You can use these `DirContext` methods to associate attributes with the object at the time that the binding or subcontext is added to the namespace. For example, you might create a `Person` object and bind it to the namespace and at the same time associate attributes about that `Person` object.

> #### Adding a Binding That Has Attributes

> `DirContext.bind()` is used to add a binding that has attributes to a context. It accepts as arguments the name of the object, the object to be bound, and a set of attributes.

> >     // Create the object to be bound
> >     Fruit fruit = new Fruit("orange");

> >     // Create attributes to be associated with the object
> >     Attributes attrs = new BasicAttributes(true); // case-ignore
> >     Attribute objclass = new BasicAttribute("objectclass");
> >     objclass.add("top");
> >     objclass.add("organizationalUnit");
> >     attrs.put(objclass);

> >     // Perform bind
> >     ctx.bind("ou=favorite, ou=Fruits", fruit, attrs);

> This example creates an object of class `Fruit` and binds it to the name `"ou=favorite"` into the context named `"ou=Fruits"`, relative to `ctx`. This binding has the `"objectclass"` attribute. If you subsequently looked up the name `"ou=favorite, ou=Fruits"` in `ctx`, then you would get the `fruit` object. If you then got the attributes of `"ou=favorite, ou=Fruits"`, you would get those attributes with which the object was created. Following is this example's output.

> >     # java Bind
> >     orange
> >     attribute: objectclass
> >     value: top
> >     value: organizationalUnit
> >     value: javaObject
> >     value: javaNamingReference
> >     attribute: javaclassname
> >     value: Fruit
> >     attribute: javafactory
> >     value: FruitFactory
> >     attribute: javareferenceaddress
> >     value: #0#fruit#orange
> >     attribute: ou
> >     value: favorite

> The extra attributes and attribute values shown are used to store information about the object (`fruit`). These extra attributes are discussed in more detail in the trail.

> If you were to run this example twice, then the second attempt would fail with a `NameAlreadyBoundException`. This is because the name `"ou=favorite"` is already bound in the `"ou=Fruits"` context. For the second attempt to succeed, you would have to use `rebind()`.

> #### Replacing a Binding That Has Attributes

> `DirContext.rebind()` is used to add or replace a binding and its attributes. It accepts the same arguments as `bind()`. However, `rebind()`'s semantics require that if the name is already bound, then it will be unbound and the newly given object and attributes will be bound.

> >     // Create the object to be bound
> >     Fruit fruit = new Fruit("lemon");

> >     // Create attributes to be associated with the object
> >     Attributes attrs = new BasicAttributes(true); // case-ignore
> >     Attribute objclass = new BasicAttribute("objectclass");
> >     objclass.add("top");
> >     objclass.add("organizationalUnit");
> >     attrs.put(objclass);

> >     // Perform bind
> >     ctx.rebind("ou=favorite, ou=Fruits", fruit, attrs);

> When you run this example, it replaces the binding that the `bind()` example created.

> >     # java Rebind
> >     lemon
> >     attribute: objectclass
> >     value: top
> >     value: organizationalUnit
> >     value: javaObject
> >     value: javaNamingReference
> >     attribute: javaclassname
> >     value: Fruit
> >     attribute: javafactory
> >     value: FruitFactory
> >     attribute: javareferenceaddress
> >     value: #0#fruit#lemon
> >     attribute: ou
> >     value: favorite

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