In -depth understanding of the principle of SPECS framework in the Java class library
In -depth understanding of the principle of SPECS framework in the Java class library
introduction:
In Java development, we often need to use class libraries to complete specific tasks.In order to improve the readability, maintenance, and scalability of the code, the design and implementation of the class library are essential.The SPECS framework is a designs widely used in the Java library, which can help us better organize and manage the law.
1. What is the SPECS framework?
The SPECS framework is a design mode based on the Specification to describe the constraints and behavioral specifications of specific objects in the class library.It encapsulates various constraints into different conventions and provides a simple and flexible way to combine these rules in order to perform verification, filtering and querying operations.
Second, the core component of the SPECS framework
1. Specification (Specification): The convention interface is the core of the Specs framework. It defines a constraint or behavioral specification and provides a method to determine whether the object meets the regulation.Under normal circumstances, the convention interface contains a method of `ISSATISFIEDBY (Object Obj) to determine whether the given object meets the rules.
2. ABSTRACTSPECICATION: The implementation class of the rules is the basis of the convention interface. It provides some commonly used combination operations, such as "with", "or" and "non -".Essence
3. SPECIFICATIONOPARATOR: The operator is an important part of the Specs framework, which is used for combination and operating rules.Under normal circumstances, the regulatory operator contains a series of methods used for the combination of the rules, such as `AND (Specification SPEC) '.The Specification SPEC) method is used to generate new rules, indicating the logic "or" of the current regulations and the given rules;
Third, the application example of the SPECS framework
In order to better understand the working principle of the Specs framework, we use a simple example to demonstrate its usage.Suppose we need to design a library to manage the user's account information, including username, password and mailbox.Next, we will use the Specs framework to organize and manage account information.
First of all, we define a specification interface `accountspecification`, and add an operation method to it` usesatisFiedby (Useraccount User) `to determine whether the user account is satisfied with the association.
public interface AccountSpecification {
boolean isSatisfiedBy(UserAccount user);
}
Then, we create a convention class' usernamespecification` to determine the conditions for determining the user name. For example, the length must be between 6 and 16 characters.
public class UsernameSpecification implements AccountSpecification {
private static final int MIN_LENGTH = 6;
private static final int MAX_LENGTH = 16;
@Override
public boolean isSatisfiedBy(UserAccount user) {
String username = user.getUsername();
return username.length() >= MIN_LENGTH && username.length() <= MAX_LENGTH;
}
}
Next, we create a convention class to implement the category `PasswordSpecification` to determine the conditions for determining passwords. For example, the length must be between 8 and 20 characters.
public class PasswordSpecification implements AccountSpecification {
private static final int MIN_LENGTH = 8;
private static final int MAX_LENGTH = 20;
@Override
public boolean isSatisfiedBy(UserAccount user) {
String password = user.getPassword();
return password.length() >= MIN_LENGTH && password.length() <= MAX_LENGTH;
}
}
Finally, we created a convention -implementation class `emailspecification` to determine the conditions of the mailbox, such as the mailbox format.
public class EmailSpecification implements AccountSpecification {
@Override
public boolean isSatisfiedBy(UserAccount user) {
String email = user.getEmail();
// True whether the format of the mailbox is correct, the specific implementation here is omitted
return isValidEmailFormat(email);
}
private boolean isValidEmailFormat(String email) {
// Check logic
// ...
}
}
Now, we can use the Specs framework to organize and manage these rules and implement some common operations.For example, we can use the "and" operator to determine whether a user account is at the same time to meet the conditions of the user name and password:
AccountSpecification usernameSpec = new UsernameSpecification();
AccountSpecification passwordSpec = new PasswordSpecification();
boolean isSatisfied = usernameSpec.and(passwordSpec).isSatisfiedBy(user);
We can also use the "or" operator to determine whether a user account meets the conditions for the user name or password:
AccountSpecification usernameSpec = new UsernameSpecification();
AccountSpecification passwordSpec = new PasswordSpecification();
boolean isSatisfied = usernameSpec.or(passwordSpec).isSatisfiedBy(user);
Finally, we can use the "non -" operating symbol to determine whether a user account does not meet the conditions of the mailbox:
AccountSpecification emailSpec = new EmailSpecification();
boolean isSatisfied = emailSpec.not().isSatisfiedBy(user);
Through these examples, we can see how the SPECS framework helps us organize and manage the rules and implement the flexible combination of the rules.
in conclusion:
The SPECS framework is a design mode commonly used in the Java library. It can help us better organize and manage the rules and improve the readability, maintenance and scalability of code.By in -depth understanding and using the Specs framework, we can better design and implement the class library, and provide a better development experience and user experience.
