1

我正在尝试使用 ChronicleWire。如特性中所述，可选字段支持开箱即用。

我刚刚创建了一个简单的自描述实体，其中包含一个可选（可为空）字段：

public class Foo extends SelfDescribingMarshallable {

  private String name;
  private Baz baz;
}

wherebaz可能或可能不是 null 并实现/扩展 Marshallable。

当我尝试将实体放入 ChronicleMap 时，出现错误：

Exception in thread "main" java.lang.NullPointerException
    at net.openhft.chronicle.bytes.BytesMarshaller$BytesMarshallableFieldAccess.getValue(BytesMarshaller.java:211)
    at net.openhft.chronicle.bytes.BytesMarshaller$FieldAccess.write(BytesMarshaller.java:152)
    at net.openhft.chronicle.bytes.BytesMarshaller.writeMarshallable(BytesMarshaller.java:70)
    at net.openhft.chronicle.bytes.BytesUtil.writeMarshallable(BytesUtil.java:295)
    at net.openhft.chronicle.bytes.BytesMarshallable.writeMarshallable(BytesMarshallable.java:48)
    at net.openhft.chronicle.bytes.BytesMarshaller$BytesMarshallableFieldAccess.getValue(BytesMarshaller.java:211)
    at net.openhft.chronicle.bytes.BytesMarshaller$FieldAccess.write(BytesMarshaller.java:152)

当我尝试改用 java optional 并且我的实体更改为：

    public class Foo extends SelfDescribingMarshallable {

      private String name;
      private Optional<Baz> baz = Optional.empty();
    }

然后引发了另一个错误：

Caused by: java.lang.IllegalArgumentException: type=class java.util.Optional is unsupported, it must either be of type Marshallable, String or AutoBoxed primitive Object
    at net.openhft.chronicle.wire.ValueOut.object(ValueOut.java:682)
    at net.openhft.chronicle.wire.ValueOut.untypedObject(ValueOut.java:795)
    at net.openhft.chronicle.wire.ValueOut.object(ValueOut.java:519)
    at net.openhft.chronicle.wire.WireMarshaller$ObjectFieldAccess.getValue(WireMarshaller.java:669)
    at net.openhft.chronicle.wire.WireMarshaller$FieldAccess.write(WireMarshaller.java:518)
    at net.openhft.chronicle.wire.WireMarshaller.writeMarshallable(WireMarshaller.java:199)
    at net.openhft.chronicle.wire.Marshallable.writeMarshallable(Marshallable.java:132)

我没有放弃并尝试实现我自己的可选。这是：

@AllArgsConstructor(staticName = "of")
@NoArgsConstructor(staticName = "empty")
public class OptionalValue<T extends Marshallable> implements Marshallable {

    @Nullable
    private T value;

    @Override
    public void readMarshallable(@NotNull WireIn wire) throws IORuntimeException {
        var val = wire.read("value");
        if (!val.isNull()) {
            val.marshallable(value);
        }
    }

    @Override
    public void writeMarshallable(@NotNull WireOut wire) {
        if (value == null) {
            wire.write("value").nu11();
        } else {
            wire.write("value").marshallable(value);
        }
    }

    boolean isEmpty() { return value == null; }

    T get() { return value; }
}

在这种情况下，我看到了另一个错误：

Caused by: java.lang.ClassCastException

    at net.openhft.chronicle.core.util.ObjectUtils.asCCE(ObjectUtils.java:294)
    at net.openhft.chronicle.core.util.ObjectUtils$ConversionFunction.apply(ObjectUtils.java:624)
    at net.openhft.chronicle.core.util.ObjectUtils$ConversionFunction.apply(ObjectUtils.java:592)
    at net.openhft.chronicle.core.ClassLocal.computeValue(ClassLocal.java:54)
    at java.base/java.lang.ClassValue.getFromHashMap(ClassValue.java:226)
    at java.base/java.lang.ClassValue.getFromBackup(ClassValue.java:208)
    at java.base/java.lang.ClassValue.get(ClassValue.java:114)
    at net.openhft.chronicle.core.util.ObjectUtils.convertTo0(ObjectUtils.java:257)
    ... 28 more
Caused by: java.lang.NoSuchMethodException: com.redacted.entity.OptionalValue.<init>(java.lang.String)
Caused by: java.lang.NoSuchMethodException: com.redacted.entity.OptionalValue.<init>(java.lang.String)

    at java.base/java.lang.Class.getConstructor0(Class.java:3349)
    at java.base/java.lang.Class.getDeclaredConstructor(Class.java:2553)
    at net.openhft.chronicle.core.util.ObjectUtils$ConversionFunction.apply(ObjectUtils.java:620)

那么有人知道如何正确修复或使用它吗？编年史线 2.22ae6

4

1 回答 1

1

照原样SelfDescribingMarshallable，BytesMarsahallableMap 更喜欢使用这种较低级别的序列化。但是，由于它的级别太低，因此不支持null值。

Marshallable您可以通过设置来告诉构建器使用valueMarshaller

.valueMarshaller(new MarshallableReaderWriter<>(Foo.class))
于 2021-10-21T09:27:26.553 回答