How to create static DynamoDB schema with List attribute

Question

Having a bean like this:

@DynamoDbBean
public class Contact {
    private String id;
    private List<String> pid;
    // getters and setters
}

When I create a StaticTableSchema for it like this:

StaticTableSchema
    .builder(Contact.class)
    .newItemSupplier(Contact::new)
    .addAttribute(List.class, a -> 
        a
            .name("pid")
            .getter(Contact::getPid)
            .setter(Contact::setPid)
    )

And then trying to use it:

DynamoDbTable<Contact> mappedTable = enhancedClient.table(tableName, Contact.TABLE_SCHEMA);

I get exception:

java.lang.ExceptionInInitializerError
    at com.childcare.service.ContactServiceIntegrationTest.testFindByEmail(ContactServiceIntegrationTest.java:60)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: java.lang.IndexOutOfBoundsException: Index: 0
    at java.base/java.util.Collections$EmptyList.get(Collections.java:4553)
    at software.amazon.awssdk.enhanced.dynamodb.DefaultAttributeConverterProvider.findConverter(DefaultAttributeConverterProvider.java:153)
    at software.amazon.awssdk.enhanced.dynamodb.DefaultAttributeConverterProvider.converterFor(DefaultAttributeConverterProvider.java:133)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.ImmutableAttribute.converterFrom(ImmutableAttribute.java:167)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.ImmutableAttribute.resolve(ImmutableAttribute.java:163)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticImmutableTableSchema.lambda$new$0(StaticImmutableTableSchema.java:153)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1624)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
    at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:312)
    at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:734)
    at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticImmutableTableSchema.<init>(StaticImmutableTableSchema.java:159)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticImmutableTableSchema.<init>(StaticImmutableTableSchema.java:77)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticImmutableTableSchema$Builder.build(StaticImmutableTableSchema.java:425)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableSchema.<init>(StaticTableSchema.java:66)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableSchema.<init>(StaticTableSchema.java:64)
    at software.amazon.awssdk.enhanced.dynamodb.mapper.StaticTableSchema$Builder.build(StaticTableSchema.java:255)
    at com.childcare.model.dyanmo.Contact.<clinit>(Contact.java:334)
    ... 25 more

What is the proper way to define a List attribute in StaticTableSchema?

Answer 1

For SDK v2 use this:

StaticTableSchema
            .builder(Contact.class)
            .newItemSupplier(Contact::new)
            .addAttribute(EnhancedType.listOf(String.class),
                          a -> a.name("pid")
                          .getter(Contact::getPid)
                          .setter(Contact::setPid)
                          .attributeConverter(ListAttributeConverter.builder(EnhancedType.listOf(String.class))
                          .collectionConstructor(ArrayList::new)                           
                          .elementConverter(StringAttributeConverter.create())
                          .build())))

you need to provide the ListAttributeConverter and the StringAttributeConverter inside it so it knows how to converts its elements