examples/simple/src/main/java/org/apache/accumulo/examples/simple/constraints/MaxMutationSize.java

/*
 * 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.accumulo.examples.simple.constraints;

import java.util.Collections;
import java.util.List;

import org.apache.accumulo.core.constraints.Constraint;
import org.apache.accumulo.core.data.Mutation;

/**
 * Ensure that mutations are a reasonable size: we must be able to fit several in memory at a time.
 *
 */
public class MaxMutationSize implements Constraint {
  static final long MAX_SIZE = Runtime.getRuntime().maxMemory() >> 8;
  static final List<Short> empty = Collections.emptyList();
  static final List<Short> violations = Collections.singletonList(Short.valueOf((short) 0));

  @Override
  public String getViolationDescription(short violationCode) {
    return String.format("mutation exceeded maximum size of %d", MAX_SIZE);
  }

  @Override
  public List<Short> check(Environment env, Mutation mutation) {
    if (mutation.estimatedMemoryUsed() < MAX_SIZE)
      return empty;
    return violations;
  }
}