在java中使用数百个if else实现业务规则的设计模式
我必须用数百行下面的代码来实现某些业务规则
if this
then this
else if
then this
.
. // hundreds of lines of rules
else
that我们是否有任何设计模式可以有效地实现这一点，或者重用代码，以便它可以应用于所有不同的规则。我听说过Specification Pattern，它创建了下面这样的东西
public interface Specification {
boolean isSatisfiedBy(Object o);
Specification and(Specification specification);
Specification or(Specification specification);
Specification not(Specification specification);
}
public abstract class AbstractSpecification implements Specification {
public abstract boolean isSatisfiedBy(Object o);
public Specification and(final Specification specification) {
return new AndSpecification(this, specification);
}
public Specification or(final Specification specification) {
return new OrSpecification(this, specification);
}
public Specification not(final Specification specification) {
return new NotSpecification(specification);
}
}然后实现Is，And，Or方法，但我认为这不能避免我编写if else(可能是我的理解不正确)……
有没有最好的方法来实现有这么多if else语句的业务规则？
编辑:只是一个示例。A，B，C等都是class.Apart的属性。还有很多类似的其他规则。我想为这个做一个泛型代码。
If <A> = 'something' and <B> = ‘something’ then
If <C> = ‘02’ and <D> <> ‘02’ and < E> <> ‘02’ then
'something'
Else if <H> <> ‘02’ and <I> = ‘02’ and <J> <> ‘02’ then
'something'
Else if <H> <> ‘02’ and <I> <> ‘02’ and <J> = ‘02’ then
'something'
Else if <H> <> ‘02’ and <I> = ‘02’ and <J> = ‘02’ then
'something'
Else if <H> = ‘02’ and <I> = ‘02’ and <J> <> ‘02’ then
'something'
Else if <H> = ‘02’ and <I> <> ‘02’ and <J> = ‘02’ then
'something'
Else if <H> = ‘02’ and <I> = ‘02’ and <J> = ‘02’ then:
If <Q> = Y then
'something'
Else then
'something'
Else :
Value of <Z>回答 5
Stack Overflow用户
发布于 2017-11-21 01:24:26
您应该查看规则设计模式http://www.michael-whelan.net/rules-design-pattern/。它看起来与您给出的示例代码非常相似，由一个基本接口组成，该接口定义了一个确定是否满足规则的方法，然后根据不同的规则实现各种具体的实现。据我所知，您的switch语句将变成某种简单的循环，它只是计算事物，直到您的规则组合被满足或失败。
interface IRule {
bool isSatisfied(SomeThing thing);
}
class RuleA: IRule {
public bool isSatisfied(SomeThing thing) {
...
}
}
class RuleB: IRule {
...
}
class RuleC: IRule {
...
}组成规则：
class OrRule: IRule {
private readonly IRule[] rules;
public OrRule(params IRule[] rules) {
this.rules = rules;
}
public isSatisfied(thing: Thing) {
return this.rules.Any(r => r.isSatisfied(thing));
}
}
class AndRule: IRule {
private readonly IRule[] rules;
public AndRule(params IRule[] rules) {
this.rules = rules;
}
public isSatisfied(thing: Thing) {
return this.rules.All(r => r.isSatisfied(thing));
}
}
// Helpers for AndRule / OrRule
static IRule and(params IRule[] rules) {
return new AndRule(rules);
}
static IRule or(params IRule[] rules) {
return new OrRule(rules);
}在事物上运行规则的一些服务方法：
class SomeService {
public evaluate(IRule rule, Thing thing) {
return rule.isSatisfied(thing);
}
}用法：
// Compose a tree of rules
var rule =
and (
new Rule1(),
or (
new Rule2(),
new Rule3()
)
);
var thing = new Thing();
new SomeService().evaluate(rule, thing);这里也回答了这个问题：https://softwareengineering.stackexchange.com/questions/323018/business-rules-design-pattern
Stack Overflow用户
发布于 2013-05-31 12:30:12
策略模式在这里可能很有用。请查看Replace Conditional Logic with Strategy
Stack Overflow用户
发布于 2013-05-31 12:20:16
像Drools这样的规则引擎可能会有所帮助。这不是一个设计模式，所以这可能不是你想要的答案。但国际海事组织，你应该考虑一下。这里有一篇关于when you should use a rules engine的很棒的文章。
https://stackoverflow.com/questions/16849656
复制相似问题