Java 非静态方法的 Consumer MethodReference

Question

代码片段：

class Scratch {

Map<ActionType, SomeConsumer<DocumentPublisher, String, String>> consumerMapping = Map.of(
        ActionType.REJECT, DocumentPublisher::rejectDocument, 
        ActionType.ACCEPT, DocumentPublisher::acceptDocument,
        ActionType.DELETE, DocumentPublisher::deleteDocument);
        

private void runProcess(DocumentAction action) {
    DocumentPublisher documentPublisher = DocumentPublisherFactory.getDocumentPublisher(action.getType);

    SomeConsumer<DocumentPublisher, String, String> consumer = consumerMapping.get(action.getType());
    consumer.apply(documentPublisher, "documentName", "testId1");
}

private interface DocumentPublisher {
    
    void rejectDocument(String name, String textId);

    void acceptDocument(String name, String textId);

    void deleteDocument(String name, String textId);
}

}

我可以使用哪种类型的功能接口来代替 SomeConsumer？这里的主要问题是它不是静态字段，而且我只会在运行时知道的对象。

我尝试使用 BiConsumer，但它告诉我不能以这种方式引用非静态方法。

Answer 1

根据您在此处的用法：

consumer.apply(documentPublisher, "documentName", "testId1");

很明显消费者消费了 3 样东西，所以它不是 BiConsumer。您需要 TriConsumer，标准库中没有。

虽然你可以自己写这样一个功能接口：

interface TriConsumer<T1, T2, T3> {
    void accept(T1 a, T2 b, T3 c);
}

如果您要给它的唯一通用参数是 <DocumentPublisher, String, String>，我认为您应该为它命名一些特定于您的应用程序的名称，例如 DocumentPublisherAction:

interface DocumentPublisherAction {
    void perform(DocumentPublisher publisher, String name, String textId);
}

Map<ActionType, DocumentPublisherAction> consumerMapping = Map.of(
        ActionType.REJECT, DocumentPublisher::rejectDocument, 
        ActionType.ACCEPT, DocumentPublisher::acceptDocument,
        ActionType.DELETE, DocumentPublisher::deleteDocument);
        

private void runProcess(DocumentAction action) {
    DocumentPublisher documentPublisher = DocumentPublisherFactory.getDocumentPublisher(action.getType);

    DocumentPublisherAction consumer = consumerMapping.get(action.getType());
    consumer.perform(documentPublisher, "documentName", "testId1");
}

Java 非静态方法的 Consumer MethodReference

Java Consumer MethodReference for nonstatic methods

java

functional-interface

method-reference