Error While Fetching Data from Corda Custom Tables

Question

How to fetch data from corda Custom tables? my sample code is as follows :-

Api layer -- getIous() method 
{
    Field attributeValue=IOUSchemaV1.PersistentIOU.class.getDeclaredField("value");
    CriteriaExpression currencyIndex = Builder.equal(attributeValue, "12");
    QueryCriteria.VaultCustomQueryCriteria criteria = new 
    QueryCriteria.VaultCustomQueryCriteria(currencyIndex);
    vaultStates = services.vaultQueryByCriteria(criteria,IOUState.class);
}

2. In ExamplePlugin I added below code for schema registration

   public class ExamplePlugin extends CordaPluginRegistry implements 
   WebServerPluginRegistry
   {
   @NotNull
   @Override
   public Set<MappedSchema> getRequiredSchemas()
   {
       Set<MappedSchema> requiredSchemas = new HashSet<>();
       requiredSchemas.add(new IOUSchemaV1());
       return requiredSchemas;
   }
   

   }

3. My Schema classes are ---

   public final class IOUSchema {
   
   }
   
   
   @CordaSerializable
   public class IOUSchemaV1 extends MappedSchema 
   {
   public IOUSchemaV1() {
       super(IOUSchema.class, 1, ImmutableList.of(PersistentIOU.class));
   }
   
   @Entity
   @Table(name = "iou_states")
   public static class PersistentIOU extends PersistentState {
   @Column(name = "sender_name") private final String senderName;
   @Column(name = "recipient_name") private final String recipientName;
   @Column(name = "value") private final int value;
   
   
   public PersistentIOU(String senderName, String recipientName, int value) {
       this.senderName = senderName;
       this.recipientName = recipientName;
       this.value = value;
   }
   
   public String getSenderName() {
       return senderName;
   }
   
   public String getRecipientName() {
       return recipientName;
   }
   
   public int getValue() {
       return value;
   }
   

   } }

4. my state has :-

   public class IOUState implements LinearState, QueryableState 
   {
   
   --- some code goes here and below methods as well.---
   @Override
   public PersistentState generateMappedObject(MappedSchema schema) {
   if (schema instanceof IOUSchemaV1) {
       return new IOUSchemaV1.PersistentIOU(
               this.sender.getName().toString(),
               this.recipient.getName().toString(),
               this.iou.getValue());
   } else {
       throw new IllegalArgumentException("Unrecognised schema $schema");
   }
   }
   
   @Override
   public Iterable<MappedSchema> supportedSchemas() {
   return ImmutableList.of(new IOUSchemaV1());
   }
   }
   

But all the time i am getting below exception.

Caused by: net.corda.core.node.services.VaultQueryException:

Please register the entity 'com.example.schema.IOUSchemaV1' class in your CorDapp's CordaPluginRegistry configuration (requiredSchemas attribute) and ensure you have declared (in supportedSchemas()) and mapped (in generateMappedObject()) the schema in the associated contract state's QueryableState interface implementation.

Can anyone please help to resolve this.

Answer 1

Try deleting implements WebServerPluginRegistry from your plugin declaration.