geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionConfigSnapshot.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.distributed.internal;

import java.util.HashSet;
import java.util.Set;


/**
 * Provides an implementation of the {@link DistributionConfig} interface for a snapshot of running
 * application's configuration. The snapshot can be taken, given to others, modified, and then
 * applied to a currently running application.
 * <p>
 * Setters will fail if called on attributes that can not be modified when a system is running.
 * <p>
 * Instances should be obtained by calling {@link RuntimeDistributionConfigImpl#takeSnapshot}.
 * <p>
 * Removed implementations of hashCode() and equals() that were throwing
 * UnsupportedOperationException. See bug #50939 if you need to override those.
 */
public class DistributionConfigSnapshot extends DistributionConfigImpl {

  private static final long serialVersionUID = 7445728132965092798L;

  private final Set modifiable;

  /**
   * Constructs an internal system config given an existing one.
   *
   * @param dc an existing system configuration.
   */
  public DistributionConfigSnapshot(DistributionConfig dc) {
    super(dc);
    modifiable = new HashSet(20);
    String[] attNames = dc.getAttributeNames();
    for (int i = 0; i < attNames.length; i++) {
      if (dc.isAttributeModifiable(attNames[i])) {
        modifiable.add(attNames[i]);
      }
    }
  }

  @Override
  protected String _getUnmodifiableMsg(String name) {
    return String.format(
        "The %s configuration attribute can not be modified while the system is running.",
        name);
  }

  @Override
  public boolean isAttributeModifiable(String name) {
    checkAttributeName(name);
    return modifiable.contains(name);
  }

  @Override
  protected boolean _modifiableDefault() {
    return true;
  }
}