一、本文主旨
所谓通用 Builder 模式构建器,就是用来在创建一个对象并对其大量赋值时,简化、美化代码的;
二、代码
import java.util.ArrayList;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Supplier;
/**
* 通用的 Builder 模式构建器
*
* @author: CipherCui
* @since 2019/8/29
*/
public class Builder<T> {
private final Supplier<T> instantiator;
private List<Consumer<T>> modifiers = new ArrayList<>();
public Builder(Supplier<T> instantiator) {
this.instantiator = instantiator;
}
public static <T> Builder<T> of(Supplier<T> instantiator) {
return new Builder<>(instantiator);
}
public <P1> Builder<T> with(Consumer1<T, P1> consumer, P1 p1) {
Consumer<T> c = instance -> consumer.accept(instance, p1);
modifiers.add(c);
return this;
}
public <P1, P2> Builder<T> with(Consumer2<T, P1, P2> consumer, P1 p1, P2 p2) {
Consumer<T> c = instance -> consumer.accept(instance, p1, p2);
modifiers.add(c);
return this;
}
public <P1, P2, P3> Builder<T> with(Consumer3<T, P1, P2, P3> consumer, P1 p1, P2 p2, P3 p3) {
Consumer<T> c = instance -> consumer.accept(instance, p1, p2, p3);
modifiers.add(c);
return this;
}
public T build() {
T value = instantiator.get();
modifiers.forEach(modifier -> modifier.accept(value));
modifiers.clear();
return value;
}
/**
* 1 参数 Consumer
*/
@FunctionalInterface
public interface Consumer1<T, P1> {
void accept(T t, P1 p1);
}
/**
* 2 参数 Consumer
*/
@FunctionalInterface
public interface Consumer2<T, P1, P2> {
void accept(T t, P1 p1, P2 p2);
}
/**
* 3 参数 Consumer
*/
@FunctionalInterface
public interface Consumer3<T, P1, P2, P3> {
void accept(T t, P1 p1, P2 p2, P3 p3);
}
}