org.apache.flume.interceptor.InterceptorChain Maven / Gradle / Ivy
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* 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.flume.interceptor;
import com.google.common.base.Preconditions;
import java.util.Iterator;
import java.util.List;
import org.apache.flume.Event;
import com.google.common.collect.Lists;
/**
* Implementation of Interceptor that calls a list of other Interceptors
* serially.
*/
public class InterceptorChain implements Interceptor {
// list of interceptors that will be traversed, in order
private List interceptors;
public InterceptorChain() {
interceptors = Lists.newLinkedList();
}
public void setInterceptors(List interceptors) {
this.interceptors = interceptors;
}
@Override
public Event intercept(Event event) {
for (Interceptor interceptor : interceptors) {
if (event == null) {
return null;
}
event = interceptor.intercept(event);
}
return event;
}
@Override
public List intercept(List events) {
for (Interceptor interceptor : interceptors) {
if (events.isEmpty()) {
return events;
}
events = interceptor.intercept(events);
Preconditions.checkNotNull(events,
"Event list returned null from interceptor %s", interceptor);
}
return events;
}
@Override
public void initialize() {
Iterator iter = interceptors.iterator();
while (iter.hasNext()) {
Interceptor interceptor = iter.next();
interceptor.initialize();
}
}
@Override
public void close() {
Iterator iter = interceptors.iterator();
while (iter.hasNext()) {
Interceptor interceptor = iter.next();
interceptor.close();
}
}
}