Java class library development guide based on the Invariant framework
Java class library development guide based on the Invariant framework
Introduction:
In the development of Java libraries, unity is an important concept.Does not degenerate whether an object can change its state in its life cycle.The constant object will remain unchanged after creation and cannot be modified.If an instance of a class is constant, its state cannot be changed, and it is visible to other objects.Uncomvitations can ensure the safety and correctness of the object, avoiding concurrent problems and data competition.The development of Java libraries based on unchanged frameworks can provide more stable and reliable code.
The key to achieving invariance is to ensure that the state of the object cannot be modified.In order to achieve unchanged, you can follow the following principles:
1. State the class as FINAL: the class is declared to final to prevent the inheritance and modification of the class.This can ensure the invariance of the class.
public final class ImmutableClass {
// class implementation
}
2. Declarize all fields as Private and FINAL: Declarize the fields of the class as Private and Final to ensure that the field cannot be modified by the external class.
public final class ImmutableClass {
private final String name;
private final int age;
public ImmutableClass(String name, int age) {
this.name = name;
this.age = age;
}
// getters
}
3. Setter method without modifying fields: The setter method of modified fields is not provided, and only the Getter method to obtain the field value is provided.This can avoid the status of an external class modification object.
public final class ImmutableClass {
private final String name;
private final int age;
public ImmutableClass(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
}
4. Prevent field references from variable objects: If a field references a variable object, then even if the class is unchanged, its state is still variable.Therefore, it is necessary to ensure that the object referenced is also immutable.
public final class ImmutableClass {
private final String name;
private final List<String> hobbies;
public ImmutableClass(String name, List<String> hobbies) {
this.name = name;
this.hobbies = Collections.unmodifiableList(new ArrayList<>(hobbies));
}
// getters
}
The advantage of constant framework is that it can ensure the stability and reliability of the class library.The constant object can be used safely in a multi -threaded environment because their state will not be modified.In addition, because the fields of unchanged objects are visible, code maintenance and debugging can be performed easier.
Summarize:
Unity is an important concept in the development of the Java library.By following some design principles, we can achieve constant objects to provide more stable and reliable class libraries.The constant object can be used safely in a multi -threaded environment, and can be easily maintained and debugged by code.
The above is the Java class library development guide based on the constant framework. I hope it will be helpful to your development work!
