Groovy流为.peek和.map提供MissingMethodException

Question

List<MolportEntryVerification> verificationList = molportEntries.stream()
          .peek{if(i++%50 == 0){println(df.format(i/count))}}
          .map({entry -> verifier.verifyEntry(entry, new Standardizer(molportConfig),  new Standardizer(bciConfig))})
          .collect(Collectors.toList())

groovy.lang.missingMethodException：方法的无签名:java.util.stream.referencePipeline$head.peek()适用于参数类型:(MolportFileverization$_run_closure1)值:[MolportFileverization$_run_closure1@d62472f]可能的解决方案:peek(java.util.function.consumer)、grep()、sleep(long)、use([ljava.lang.object；)、grep(java.lang.object)、wait()

长count=molportentries.stream（）.count（）；

工作时没有错误信息。

public class BasicMolportEntry {
    public BasicMolportEntry(String molportId, String etxcId, String smiles) {
        this.molportId = molportId == null ? "" : molportId;
        this.etxcId = etxcId == null ? "" : etxcId;
        this.smiles = smiles;
    }

加上所有平常的...

有什么建议吗？

Answer 1

以下代码：

class MolportEntryVerification {}
class BasicMolportEntry {}

def molportEntries = (1..200).collect { new BasicMolportEntry() }

def i = 0
List<MolportEntryVerification> result = molportEntries.stream()
  .peek { if(i++%50 == 0) { println(i-1) } }
  .map  { e -> new MolportEntryVerification() }
  .toList()

println "size: ${result.size()}"

模仿问题中的代码在groovy 2.5.7中可以正常工作，在groovy 2.3.9中缺少tolist()（代码中没有该代码，但它是收集器语法的缩写），并出现以下错误：

~> groovy solution.groovy

Caught: groovy.lang.MissingMethodException: No signature of method: java.util.stream.ReferencePipeline$Head.peek() is applicable for argument types: (solution$_run_closure2) values: [solution$_run_closure2@d706f19]
Possible solutions: peek(java.util.function.Consumer), grep(), sleep(long), use([Ljava.lang.Object;), grep(java.lang.Object), wait()
groovy.lang.MissingMethodException: No signature of method: java.util.stream.ReferencePipeline$Head.peek() is applicable for argument types: (solution$_run_closure2) values: [solution$_run_closure2@d706f19]
Possible solutions: peek(java.util.function.Consumer), grep(), sleep(long), use([Ljava.lang.Object;), grep(java.lang.Object), wait()
    at solution.run(solution.groovy:7)

在groovy 1.8.8中。这看起来与您所遇到的MissingMethodException相同。