// Copyright 2010 Google Inc.
//
// 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 com.google.enterprise.connector.util.diffing;
import com.google.common.base.Preconditions;
import com.google.enterprise.connector.spi.TraversalContext;
import java.util.concurrent.atomic.AtomicReference;
/**
* Holder for the {@link TraversalContext}.
*
* @since 2.8
*/
public class TraversalContextManager {
private final AtomicReference<TraversalContext> traversalContext =
new AtomicReference<TraversalContext>();
/**
* Sets the {@link TraversalContext}.
*
* @param traversalContext the {@link TraversalContext} to hold - must not be
* {@code null}
*/
public void setTraversalContext(TraversalContext traversalContext) {
Preconditions.checkNotNull(traversalContext,
"traversalContext must not be null.");
this.traversalContext.set(traversalContext);
}
/**
* @return the {@link TraversalContext}
*/
public TraversalContext getTraversalContext() {
TraversalContext result = traversalContext.get();
Preconditions.checkState((result != null),
"setTraversalContext has not been called.");
return result;
}
}