Examples for Builder and ProtoType

[Sujatha Kumar]

Hi,

Can anyone let me know, where could i find the examples
for Builder and ProtoType pattern.

Your help is highly appreciated.

Regards
Prathap.

[steve souza]

The java clone() method is an example of the prototype pattern. the definition of prototype is: "Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype". This is what the java clone() method does.

[Sujatha Kumar]

Can i have an example for a Builder.

Regards

[steve souza]

Builder definition from Gang of 4 - Separate the construction of a complex object from its representation so that the same construction process can create different representations.

Here is a link:
http://www.fact-index.com/b/bu/builder_pattern.html

Some of the creational patterns are a little blurry to me. I created a class called ArraySQL that allows you to type in a sql string and I parse that String to create the appropriate objects behind the scenes. The developer that uses my class has no idea what objects I create from there request. I think that fits the builder pattern as described above, but most examples don't use parsed Strings to build objects on the fly, so I'm not sure if it is the builder pattern or not.

Here is an example of ArraySQL. Note that different objects are created behind the scenes depending on whether a display column is a function or wha t type of where clause is being used i.e. in, =, <=, != etc.

 
// The select statement is an example of the builder pattern as it fits the definition quite well. 
ArraySQL asql=new ArraySQL("select rowNum(), * from array where lname in ('jones', 'smith') || fname='steve' order by lname desc");
Object[][] data=...
data=asql.execute(data); // execute the query on the array