英文:
Optional Java Builder Functions
问题
我正在使用一个导入的JAR包。在那个JAR包中，他们只允许使用构建器来创建对象。
例如：
public PersonBuilder oneRelation() {
Person person = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith")
.relation(relationObject.builder().Name("Cousin").build());
}
public PersonBuilder twoRelation() {
return PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith")
.relation(relationObject.builder().Name("Parent").build())
.relation(relationObject.builder().Name("Sibling").build());
}
我不得不创建多个方法来处理拥有多个关系的情况。不幸的是，如果我向关系传递空值，它会给我一个错误。
有没有人成功地动态创建过一个构建器？我已经稍微修改了它，以便将一个关系传递给它，并使函数利用关系数组的大小。然而，我仍然需要在所有可能的关系数量上重复firstName和lastName。
英文:
I'm working with an imported jar. In that Jar, they only allow builders to create objects.
I.E.
public PersonBuilder oneRelation(){
person person = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith")
.relation(relationObject.builder().Name("Cousin").build())}
public PersonBuilder twoRelation(){
return PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith")
.relation(relationObject.builder().Name("Parent").build())
.relation(relationObject.builder().Name("Sibling").build())}
I have to create multiple methods to handle having multiple relationships. Unfortunately, if I pass a null to the relation it gives me an error.
Has anyone had any luck dynamically creating a builder? I have modified it a bit to pass in a relation and have the function utilize the size of the relation array. However, I'm still duplicating the firstName and lastName over the total number of relationships I can have.
答案1
得分: 0
一个构建器只是一个对象，因此只需创建一个它的局部变量，并通过链式的 .relation() 方法进行循环。
public PersonBuilder relations(List<RelationObject> relations) {
PersonBuilder builder = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith");
relations.forEach(builder::relation);
return builder;
}
你可以这样调用它：
relations(Arrays.asList(relationObject.builder().Name("Cousin").build()))
relations(Arrays.asList(relationObject.builder().Name("Parent").build(),
relationObject.builder().Name("Sibling").build()))
你还可以使用可变参数（varargs），这样就不必创建列表：
public PersonBuilder relations(RelationObject... relations) {
PersonBuilder builder = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith");
for (RelationObject relation : relations) {
builder.relation(relation);
}
return builder;
}
你可以这样调用它：
relations(relationObject.builder().Name("Cousin").build())
relations(relationObject.builder().Name("Parent").build(),
relationObject.builder().Name("Sibling").build())
英文:
A builder is just an object so just create a local variable of it and loop through the chained .relation() method.
public PersonBuilder relations(List<RelationObject> relations) {
PersonBuilder builder = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith");
relations.forEach(builder::relation);
return builder;
}
And you can call it like this:
relations(Arrays.asList(relationObject.builder().Name("Cousin").build()))
relations(Arrays.asList(relationObject.builder().Name("Parent").build(),
relationObject.builder().Name("Sibling").build()))
You can also use varargs so you don't have to create a list:
public PersonBuilder relations(RelationObject... relations) {
PersonBuilder builder = PersonBuilder.builder()
.firstName("Tom")
.lastName("Smith");
for (RelationObject relation : relations) {
builder.relation(relation);
}
return builder;
}
And you can call it like this:
relations(relationObject.builder().Name("Cousin").build())
relations(relationObject.builder().Name("Parent").build(),
relationObject.builder().Name("Sibling").build())
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