Question

我对Scala很陌生，我尝试将一些JSF控制器转换为Scala进行一些测试。代码如下：

abstract class BaseListBean[TENTITY <: AnyRef, TID <: AnyRef] extends Serializable {

  @BeanProperty var current:TENTITY = _

  @BeanProperty var lazyDataModel: LazyDataModel[TENTITY] = _

  def initLazyDataModel(): LazyDataModel[TENTITY] = {

    val model:LazyDataModel[TENTITY] = new LazyDataModel[TENTITY]() {

      override def load(first: Int, pageSize: Int, sortField: String, sortOrder: SortOrder, filters: util.Map[String, AnyRef]): util.List[TENTITY] = {

        val paginationInfo:PaginationInfo = new PaginationInfo()
        paginationInfo.setFromRecord(first)
        paginationInfo.setPageSize(pageSize)
        paginationInfo.setSortBy(Array(sortField))
        paginationInfo.setDirections(if (SortOrder.ASCENDING == sortOrder) Array(Direction.Asc) else Array(Direction.Desc))

        val advisoryPaginatedResult:PaginatedResult[TENTITY] = getBaseCRUD.read(paginationInfo)
        setRowCount(advisoryPaginatedResult.getTotalItems.toInt)

        advisoryPaginatedResult getItems
      }

      override def getRowKey(obj: TENTITY): TID = getEntityKey(obj)

    }

    return model;

  }



  def init() = {
    setLazyDataModel(initLazyDataModel())

  }

  def getEntityKey(obj: TENTITY) : TID
  def getBaseCRUD() : BaseCRUD[TENTITY, TID]
  def customInit() = {

  }

}

编译时的错误是：

错误：（24,34）类型不匹配;

发现：org.primefaces.model.org.primefaces.model.LazyDataModel [TENTITY]

必需：org.primefaces.model.org.primefaces.model.LazyDataModel [TENTITY]
val model:LazyDataModel[TENTITY] = new LazyDataModel[TENTITY]() {

我搜索解决方案，但问题仍然重新设定。我试着用这样简单的代码重现：

abstract class ExampleGenerics[T <: AnyRef, V <: AnyRef] {

  @BeanProperty var list:util.AbstractMap[T, V] = _

  def initList() : util.AbstractMap[T, V] = {
    val model:util.AbstractMap[T, V] = new util.AbstractMap[T, V]() {
      override def entrySet(): util.Set[Entry[T, V]] = {
        return null;
      }
    }
    return model
  }

  def init() = {
    setList(initList());
  }

}

但这会奏效。有人可以帮忙吗？感谢

Answer 1

我发现了问题：

这是LazyDataModel<T>：

的负责人

public abstract class LazyDataModel<T> extends DataModel<T> implements SelectableDataModel<T>, Serializable { /*...*/ }

该类继承自DataModel<T>。

在我的pom.xml中我有

    <dependency>
        <groupId>javax.faces</groupId>
        <artifactId>javax.faces-api</artifactId>
        <version>2.0</version>
        <scope>provided</scope>
    </dependency>

以及

<dependency>
    <groupId>javaee</groupId>
    <artifactId>javaee-api</artifactId>
    <version>5</version>
    <scope>provided</scope>
</dependency>

类DataModel<T>在jsf 2包中，但在javaee-api中有DataModel类（没有泛型）。所以编译器出错了。解决方案是使用以下依赖项修改pom：

<dependency>
    <groupId>javax.ejb</groupId>
    <artifactId>ejb-api</artifactId>
    <version>3.0</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>servlet-api</artifactId>
    <version>2.5</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>javax.faces</groupId>
    <artifactId>javax.faces-api</artifactId>
    <version>2.0</version>
    <scope>provided</scope>
</dependency>

我无法使用jee6 api依赖，因为我使用jee5兼容的应用服务器和JSF2.0升级。

Scala类型与泛型不匹配

1 个答案: