如何在Olingo V4中创建有限动作(java) [英] How to create a bounded action in Olingo V4 (java)

问题描述

我尝试到处寻找，但无法弄清楚如何在olingo V4 java中实现有限动作.

I have tried looking everywhere but couldn't figure out how to implement bounded actions in olingo V4 java.

给出了无处不在的动作教程.

Everywhere unbounded action tutorial is given.

我尝试调整此代码.

  final CsdlAction action = new CsdlAction();
  action.setName("testAction");
  action.setBound(true);

当我尝试访问$ metadata API时，这给了我错误.

This gives me error when I try to access $metadata API.

如果任何人都可以指导我找到有关如何进行的良好教程，那就太好了.

If anyone can point me towards a good tutorial on how to go about it then it would be great.

推荐答案

我研究了olingo的源代码并调试了它们的代码.经过大量研究工作，我得以在Olingo中实施有限动作.

I looked into the source code of olingo and debugged their code. After a lot of research work I was able to implement bounded actions in Olingo.

假设我们要实现一个绑定动作，该动作绑定到实体类型X，并返回实体Y.

Suppose we want to implement a bounded action which is bounded to an entity type X and which return an entity Y.

需要进行的更改是:

元数据文档: 在扩展CsdlAbstractEdmProvider或实现CsdlEdmProvider的Java类(自定义类)中，

Metadata Document: In your java class (custom class) which extends CsdlAbstractEdmProvider or implements CsdlEdmProvider,

实现getActions(...)函数

implement getActions(...) functions

// Action Names
public static final String ACTION_EXECUTE_NAME = "Execute";

// FullyQualified Action Names
public static final FullQualifiedName ACTION_EXECUTE_FQN = new FullQualifiedName("StackOverflow", ACTION_EXECUTE_NAME);

@Override
public List<CsdlAction> getActions(FullQualifiedName actionName) throws ODataException {
    if (actionName.equals(ACTION_EXECUTE_FQN)) {
        // It is allowed to overload actions, so we have to provide a list
        // of Actions for each action name
        final List<CsdlAction> actions = new ArrayList<CsdlAction>();

        // Create the Csdl Action
        final CsdlAction action = new CsdlAction();
        action.setName(ACTION_EXECUTE_FQN.getName());
        action.setBound(true);

        // Creating Parameter the first one being binding parameter
        final List<CsdlParameter> parameters = new ArrayList<CsdlParameter>();
        final CsdlParameter parameter = new CsdlParameter();
        parameter.setName("Parameter1");
        parameter.setType(X);
        parameter.setNullable(true);
        parameter.setCollection(false);
        parameters.add(parameter);
        action.setParameters(parameters);

        action.setReturnType(new CsdlReturnType().setCollection(false).setType(Y));

        actions.add(action);
        return actions;
    }
    return null;
}

并在相同的元数据提供程序类的getSchemas(...)中，调用getActions(...)方法.

and in the getSchemas(...) of the same metadata provider class cal the getActions(...) method.

@Override
public List<CsdlSchema> getSchemas() throws ODataException {
    // create Schema
    CsdlSchema schema = new CsdlSchema();
    schema.setNamespace("Stackoverflow");

    // add EntityTypes
    List<CsdlEntityType> entityTypes = new ArrayList<CsdlEntityType>();
    entityTypes.add(getEntityType(X));
    entityTypes.add(getEntityType(Y));

    schema.setEntityTypes(entityTypes);

    // add EntityContainer
    schema.setEntityContainer(getEntityContainer());

    // add bounded actions
    List<CsdlAction> actions = new ArrayList<CsdlAction>();
    schema.setActions(actions);
    actions.addAll(getActions(ACTION_EXECUTE_FQN));

    List<CsdlSchema> schemas = new ArrayList<CsdlSchema>();
    schemas.add(schema);
    return schemas;
}

我们要做的是，创建了一个名为ACTION_EXECUTE_FQN的有界操作，该操作以参数作为操作的第一个参数，在我们的示例中为实体X，返回类型为实体Y.

what we have done is that, created a bounded a action named ACTION_EXECUTE_FQN with parameter as first argument of action, in our case being the entity X and return type is entity Y.

服务实施: 现在，还需要实现服务.根据使用的用例，我们需要创建一个实现 ActionEntityProcessor 的类.

Service Implementation: Now, service implementation is also needed. According to the use case which has been taken, we need a create a class implementing ActionEntityProcessor .

此后，一切都相同.我希望这将有所帮助.还有其他ActionProcessor，具体取决于操作的返回类型和操作所绑定到的参数的类型.

After this, everything is same. I hope this will help. There are other ActionProcessors depending on the return type of actions and the type of parameter to which action is bounded.

这篇关于如何在Olingo V4中创建有限动作(java)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！