Detailed explanation of the Invariant framework
Detailed explanation of the Invariant framework
Invariant is an important concept of Java programming. It refers to the state of an object in its life cycle that will not change.In the Java class library, some frameworks and technologies are provided to support invariability to ensure the safety and reliability of the object during use.
After the creation is created, the internal state cannot be modified.This means that once the object is initialized, it will not change again.It is very important in multi -threaded programming because there is no need to worry about the complication caused by the changes of the object by other threads.The following is an example to illustrate how to create an immutable Java class.
public final class ImmutableClass {
private final int value;
private final String name;
public ImmutableClass(int value, String name) {
this.value = value;
this.name = name;
}
public int getValue() {
return value;
}
public String getName() {
return name;
}
}
In the above examples, `IMMUTableClass` is an unavailable class.It uses the `Final` keyword to ensure that the class cannot be inherited.All fields of the class are declared as `Final` and initialize in the constructor.By providing only the accessor method without modifiers, the state of the object cannot be modified by the outside.
There are many benefits of non -mutinal classes.First of all, they can be freely shared because multiple references are safe to the same object.Secondly, it is easier to test and debug in non -changing classes, because the state will not change after creation.In addition, because there is no modifier method for non -changing classes, they are safe threads and can be used in multi -threaded environment without extra synchronization.
In addition to creating unavailable classes, the Java library also provides some other technologies to support invariability.For example, the `java.lang.string` class is an unavailable example.Each method does not modify the original object, but returns a new string object.
In addition, the `java.util.Collections` class in the Java class library provides some static methods to create uncharacteristic sets, such as` unmodifiablelist () `,` unmodified () `and` unmodifiablemap () `, etc.The collection objects returned by these methods are immutable and cannot be modified.
Invariant is a powerful programming concept, and there are many ways in the Java library that can support constant.By creating an unspeakable or unavailable data structure provided, the state of the object in its life cycle can not change, and the reliability and security of the code can be improved.
