extensions/geode-modules/src/main/java/org/apache/geode/modules/util/RegionSizeFunction.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.geode.modules.util;

import java.io.DataInput;
import java.io.DataOutput;
import java.util.Collection;
import java.util.Collections;

import org.apache.geode.DataSerializable;
import org.apache.geode.cache.Declarable;
import org.apache.geode.cache.execute.Function;
import org.apache.geode.cache.execute.FunctionContext;
import org.apache.geode.cache.execute.RegionFunctionContext;
import org.apache.geode.security.ResourcePermission;

public class RegionSizeFunction implements Function, Declarable, DataSerializable {
  private static final long serialVersionUID = -2791590491585777990L;
  public static final String ID = "region-size-function";

  public RegionSizeFunction() {}

  @Override
  @SuppressWarnings("unchecked")
  public void execute(FunctionContext context) {
    RegionFunctionContext rfc = (RegionFunctionContext) context;
    context.getResultSender().lastResult(rfc.getDataSet().size());
  }

  @Override
  public Collection<ResourcePermission> getRequiredPermissions(String regionName) {
    return Collections.singletonList(new ResourcePermission(ResourcePermission.Resource.DATA,
        ResourcePermission.Operation.READ, regionName));
  }

  @Override
  public String getId() {
    return ID;
  }

  @Override
  public boolean hasResult() {
    return true;
  }

  @Override
  public boolean optimizeForWrite() {
    return true;
  }

  @Override
  public boolean isHA() {
    return true;
  }

  @Override
  public void toData(DataOutput out) {}

  @Override
  public void fromData(DataInput in) {}
}