英文:
How can I create an ImmutableList as a member variable?
问题
我需要创建一个ImmutableList作为成员变量。
以下是我尝试过的代码：
private List<String> stringList = Arrays.asList("a", "b", "c");
private ImmutableList<String> stringList2 = Collections.unmodifiableList(stringList);
这会导致编译错误：
FakeRemoteDataStore.java:59: error: incompatible types: no instance(s) of type variable(s) T exist so that List<? extends T> conforms to ImmutableList<String>
private ImmutableList<String> stringList2 = Collections.unmodifiableList(stringList);
^
where T is a type-variable:
T extends Object declared in method <T>unmodifiableList(List<? extends T>)
我如何在成员变量中创建ImmutableList？
英文:
I need to create an ImmutableList as a member variable.
Here's what I tried:
private List<String> stringList = Arrays.asList("a", "b", "c");
private ImmutableList<String> stringList2 = Collections.unmodifiableList(stringList);
This fails to compile with the error:
FakeRemoteDataStore.java:59: error: incompatible types: no instance(s) of type variable(s) T exist so that List<T> conforms to ImmutableList<String>
private ImmutableList<String> stringList2 = Collections.unmodifiableList(stringList);
^
where T is a type-variable:
T extends Object declared in method <T>unmodifiableList(List<? extends T>)
How can I create an ImmutableList as a member variable?
答案1
得分: 1
ImmutableList是Guava的一部分，因此您可以直接这样做：
private ImmutableList<String> stringList = ImmutableList.of("a", "b", "c");
英文:
ImmutableList is part of Guava, so you can just do:
private ImmutableList<String> stringList = ImmutableList.of("a", "b", "c");
答案2
得分: 1
你可以使用ImmutableList中的copyOf函数：
ImmutableList<String> stringList2 = ImmutableList.copyOf(stringList);
英文:
You can use copyOf function from ImmutableList
ImmutableList<String> stringList2 = ImmutableList.copyOf(stringList);
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