/**
 * Copyright © 2018 spring-data-dynamodb (https://github.com/derjust/spring-data-dynamodb)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.socialsignin.spring.data.dynamodb.utils;

import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
import org.socialsignin.spring.data.dynamodb.exception.BatchWriteException;
import org.springframework.dao.DataAccessException;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.stream.Collectors;

public interface ExceptionHandler {

	default <T extends DataAccessException> T repackageToException(List<DynamoDBMapper.FailedBatch> failedBatches,
			Class<T> targetType) {
		// Error handling:
		Queue<Exception> allExceptions = failedBatches.stream().map(it -> it.getException())
				.collect(Collectors.toCollection(LinkedList::new));

		// The first exception is hopefully the cause
		Exception cause = allExceptions.poll();
		try {
			Constructor<T> ctor = targetType.getConstructor(String.class, Throwable.class);
			T e = ctor.newInstance("Processing of entities failed!", cause);
			// and all other exceptions are 'just' follow-up exceptions
			allExceptions.stream().forEach(e::addSuppressed);
			return e;
		} catch (NoSuchMethodException | InstantiationException | IllegalAccessException
				| InvocationTargetException e) {
			assert false; // we should never end up here
			throw new RuntimeException("Could not repackage '" + failedBatches + "' to " + targetType, e);
		}
	}
}

/**
 * Copyright © 2018 spring-data-dynamodb (https://github.com/derjust/spring-data-dynamodb)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.socialsignin.spring.data.dynamodb.utils;

import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;g
import org.springframework.dao.DataAccessException;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.stream.Collectors;

public interface ExceptionHandler {

	default <T extends DataAccessException> T repackageToException(List<DynamoDBMapper.FailedBatch> failedBatches,
			Class<T> targetType) {
		// Error handling:
		Queue<Exception> allExceptions = failedBatches.stream().map(it -> it.getException())
				.collect(Collectors.toCollection(LinkedList::new));

		// The first exception is hopefully the cause
		Exception cause = allExceptions.poll();
		try {
			Constructor<T> ctor = targetType.getConstructor(String.class, Throwable.class);
			T e = ctor.newInstance("Processing of entities failed!", cause);
			// and all other exceptions are 'just' follow-up exceptions
			allExceptions.stream().forEach(e::addSuppressed);
			return e;
		} catch (NoSuchMethodException | InstantiationException | IllegalAccessException
				| InvocationTargetException e) {
			assert false; // we should never end up here
			throw new RuntimeException("Could not repackage '" + failedBatches + "' to " + targetType, e);
		}
	}
}

Fix unused imports