Issue #108: Opened constructor and fixed NPE (#115)

Issue #108: Opened constructor and fixed NPE

In some use cases it is required to pass in all three parameters into
`DynamoDBTemplate` - therefore made the internal constructor public (that
was used by all other constructors anyway)

Also passing in a combination of `null`/non-`null` parameters could lead
to NPEs down the road - ie. by calling `getOverrideTableName`.
The constructor now initalizes all fields with non-`null` objects and does
not relay on AWS constructors to pick some proper default configs.

src/main/java/org/socialsignin/spring/data/dynamodb/core/DynamoDBTemplate.java

@@ -30,6 +30,9 @@
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.util.Assert;
 
+import java.util.List;
+import java.util.Map;
+
 public class DynamoDBTemplate implements DynamoDBOperations, ApplicationContextAware {
 
 	private final DynamoDBMapper dynamoDBMapper;
@@ -44,7 +47,6 @@ public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB, DynamoDBMapperConfig dyna
 	}
 
 	/** Convenient constructor to use the {@link DynamoDBMapperConfig#DEFAULT} */
-
     public DynamoDBTemplate(AmazonDynamoDB amazonDynamoDB, DynamoDBMapper dynamoDBMapper)
     {
         this(amazonDynamoDB, null, dynamoDBMapper);

src/test/java/org/socialsignin/spring/data/dynamodb/core/DynamoDBTemplateUnitTest.java

@@ -4,6 +4,8 @@
 import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
 import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig;
 import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig.TableNameResolver;
+import com.amazonaws.services.dynamodbv2.document.DynamoDB;
+
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Rule;
@@ -61,7 +63,7 @@ public void testConstructorOptionalAllNull() {
 	}
 
 	@Test
-	public void testPreconfiguredDynamoDBMapper() {
+	public void testConstructorOptionalPreconfiguredDynamoDBMapper() {
 		// Introduced constructor via #91 should not fail its assert
 		DynamoDBTemplate usePreconfiguredDynamoDBMapper = new DynamoDBTemplate(dynamoDB, dynamoDBMapper);
 

src/test/java/org/socialsignin/spring/data/dynamodb/mapping/event/ValidatingDynamoDBEventListenerTest.java

@@ -1,9 +1,5 @@
 package org.socialsignin.spring.data.dynamodb.mapping.event;
 
-import com.amazonaws.services.dynamodbv2.document.Expected;
-import net.bytebuddy.pool.TypePool;
-import org.hamcrest.core.CombinableMatcher;
-import org.hamcrest.core.StringContains;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -20,11 +16,9 @@
 import java.util.Set;
 import javax.validation.Path;
 import javax.validation.Validator;
-import javax.validation.metadata.ConstraintDescriptor;
 
 import java.util.HashSet;
 import java.util.Set;
-import java.util.concurrent.ExecutionException;
 
 import static org.hamcrest.CoreMatchers.allOf;
 import static org.hamcrest.CoreMatchers.containsString;