java - Gremlin Java - 设置属性值列表

Question

我正在使用 gremlin-java 访问 AWS Neptune。我想使用值列表设置顶点属性的值。我尝试执行以下操作:

g.V(<id of vertex>).property(Cardinality.set, "countries", new HashSet<>()).next();

执行时出现以下异常:

Caused by: org.apache.tinkerpop.gremlin.driver.exception.ResponseException: {"requestId":"39207d15-75df-4e04-9c25-574070c94687","code":"UnsupportedOperationException","detailedMessage":"Unsupported property value type: java.util.LinkedHashSet"}
at org.apache.tinkerpop.gremlin.driver.Handler$GremlinResponseHandler.channelRead0(Handler.java:259)
at org.apache.tinkerpop.gremlin.driver.Handler$GremlinResponseHandler.channelRead0(Handler.java:198)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at org.apache.tinkerpop.gremlin.driver.Handler$GremlinSaslAuthenticationHandler.channelRead0(Handler.java:124)
at org.apache.tinkerpop.gremlin.driver.Handler$GremlinSaslAuthenticationHandler.channelRead0(Handler.java:68)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at org.apache.tinkerpop.gremlin.driver.handler.WebSocketClientHandler.channelRead0(WebSocketClientHandler.java:89)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:328)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:302)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1421)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:930)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:697)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:632)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:549)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:511)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

我在网上发现，要使用值列表设置属性的值，我可以使用相同的属性键多次调用 property() 函数。但我想知道是否有一种更优雅的方法来做到这一点，而不是必须循环遍历集合中的所有值。

谢谢。

Answer 1

恐怕您需要多次调用property(SET, 'key', ...)。如果您发现您在代码中做得足够多，您可能会考虑编写 Gremlin DSL扩展语言以允许您指定一个Set，然后将其转换为预期的语法。