/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.runtime.accumulators;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.accumulators.Accumulator;
import org.apache.flink.runtime.executiongraph.ExecutionAttemptID;
import org.apache.flink.util.SerializedValue;

import java.io.IOException;
import java.io.Serializable;
import java.util.Map;

/**
 * This class encapsulates a map of accumulators for a single task. It is used
 * for the transfer from TaskManagers to the JobManager and from the JobManager
 * to the Client.
 */
public class AccumulatorSnapshot implements Serializable {

	private static final long serialVersionUID = 42L;

	private final JobID jobID;
	private final ExecutionAttemptID executionAttemptID;

	/**
	 * Flink internal accumulators which can be deserialized using the system class loader.
	 */
	private final SerializedValue<Map<AccumulatorRegistry.Metric, Accumulator<?, ?>>> flinkAccumulators;

	/**
	 * Serialized user accumulators which may require the custom user class loader.
	 */
	private final SerializedValue<Map<String, Accumulator<?, ?>>> userAccumulators;

	public AccumulatorSnapshot(JobID jobID, ExecutionAttemptID executionAttemptID,
							Map<AccumulatorRegistry.Metric, Accumulator<?, ?>> flinkAccumulators,
							Map<String, Accumulator<?, ?>> userAccumulators) throws IOException {
		this.jobID = jobID;
		this.executionAttemptID = executionAttemptID;
		this.flinkAccumulators = new SerializedValue<Map<AccumulatorRegistry.Metric, Accumulator<?, ?>>>(flinkAccumulators);
		this.userAccumulators = new SerializedValue<Map<String, Accumulator<?, ?>>>(userAccumulators);
	}

	public JobID getJobID() {
		return jobID;
	}

	public ExecutionAttemptID getExecutionAttemptID() {
		return executionAttemptID;
	}

	/**
	 * Gets the Flink (internal) accumulators values.
	 * @return the serialized map
	 */
	public Map<AccumulatorRegistry.Metric, Accumulator<?, ?>> deserializeFlinkAccumulators() throws IOException, ClassNotFoundException {
		return flinkAccumulators.deserializeValue(ClassLoader.getSystemClassLoader());
	}

	/**
	 * Gets the user-defined accumulators values.
	 * @return the serialized map
	 */
	public Map<String, Accumulator<?, ?>> deserializeUserAccumulators(ClassLoader classLoader) throws IOException, ClassNotFoundException {
		return userAccumulators.deserializeValue(classLoader);
	}
}

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.flink.runtime.accumulators;

import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.accumulators.Accumulator;
import org.apache.flink.runtime.executiongraph.ExecutionAttemptID;
import org.apache.flink.util.SerializedValue;

import java.io.IOException;
import java.io.Serializable;
import java.util.Map;

/**
 * This class encapsulates a map of accumulators for a single task. It is used
 * for the transfer from TaskManagers to the JobManager and from the JobManager
 * to the Client.
 */
public class AccumulatorSnapshot implements Serializable {

	private static final long serialVersionUID = 42L;

	private final JobID jobID;
	private final ExecutionAttemptID executionAttemptID;

	/**
	 * Flink internal accumulators which can be deserialized using the system class loader.
	 */
	private final SerializedValue<Map<AccumulatorRegistry.Metric, Accumulator<?, ?>>> flinkAccumulators;

	/**
	 * Serialized user accumulators which may require the custom user class loader.
	 */
	private final SerializedValue<Map<String, Accumulator<?, ?>>> userAccumulators;

	public AccumulatorSnapshot(JobID jobID, ExecutionAttemptID executionAttemptID,
							Map<AccumulatorRegistry.Metric, Accumulator<?, ?>> flinkAccumulators,
							Map<String, Accumulator<?, ?>> userAccumulators) throws IOException {
		this.jobID = jobID;
		this.executionAttemptID = executionAttemptID;
		this.flinkAccumulators = new SerializedValue<Map<AccumulatorRegistry.Metric, Accumulator<?, ?>>>(flinkAccumulators);
		this.userAccumulators = new SerializedValue<Map<String, Accumulator<?, ?>>>(userAccumulators);
	}

	public JobID getJobID() {
		return jobID;
	}

	public ExecutionAttemptID getExecutionAttemptID() {
		return executionAttemptID;
	}

	/**
	 * Gets the Flink (internal) accumulators values.
	 * @return the serialized map
	 */
	public Map<AccumulatorRegistry.Metric, Accumulator<?, ?>> deserializeFlinkAccumulators() throws IOException, ClassNotFoundException {
		return flinkAccumulators.deserializeValue(getClass().getClassLoader());
	}

	/**
	 * Gets the user-defined accumulators values.
	 * @return the serialized map
	 */
	public Map<String, Accumulator<?, ?>> deserializeUserAccumulators(ClassLoader classLoader) throws IOException, ClassNotFoundException {
		return userAccumulators.deserializeValue(classLoader);
	}
}

Use AccumulatorSnapshot's class loader for deserializing accumulators