/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.core;
import java.io.IOException;
import java.util.Map.Entry;
import com.cloudera.flume.conf.Context;
import com.cloudera.flume.conf.SinkFactory.SinkDecoBuilder;
import com.google.common.base.Preconditions;
/**
* Simple useful class - replace the body of an event with a formatted string.
* e.g. format("Number of requests: %b")
*
* Useful in particular for low-volume alerting / messaging.
*/
public class FormatterDecorator<S extends EventSink> extends
EventSinkDecorator<S> {
final String formatString;
public FormatterDecorator(S s, String formatString) {
super(s);
Preconditions.checkNotNull(formatString);
this.formatString = formatString;
}
/**
* Replaces e with an event whose body is formatString substituted with e's
* body
*/
public void append(Event e) throws IOException, InterruptedException {
Preconditions.checkNotNull(e);
String body = e.escapeString(formatString);
Event e2 = new EventImpl(body.getBytes(), e.getTimestamp(),
e.getPriority(), e.getNanos(), e.getHost());
for (Entry<String, byte[]> entry : e.getAttrs().entrySet()) {
e2.set(entry.getKey(), entry.getValue());
}
super.append(e2);
}
public static SinkDecoBuilder builder() {
return new SinkDecoBuilder() {
@Override
public EventSinkDecorator<EventSink> build(Context context,
String... argv) {
Preconditions.checkArgument(argv.length == 1, "usage: format(pattern)");
return new FormatterDecorator<EventSink>(null, argv[0]);
}
};
}
}