AggregateCounterHandler.java

/*
 * Copyright 2011-2013 the original author or authors.
 *
 * 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 org.springframework.xd.analytics.metrics.integration;

import java.text.ParseException;

import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.ISODateTimeFormat;

import org.springframework.expression.Expression;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;
import org.springframework.xd.analytics.metrics.core.AggregateCounterRepository;

/**
 * Handles incoming messages for the {@code aggregate-counter} module, resolves SpEL expressions
 * as needed and delegate the heavy lifting to an {@link AggregateCounterRepository}.
 *
 * @author Luke Taylor
 * @author Eric Bottard
 */
public class AggregateCounterHandler extends AbstractMetricHandler {

	private final AggregateCounterRepository aggregateCounterRepository;

	private DateTimeFormatter dateFormat = ISODateTimeFormat.dateTime();

	private final Expression incrementExpression;

	public AggregateCounterHandler(AggregateCounterRepository aggregateCounterRepository, String nameExpression,
			String incrementExpression) {
		super(nameExpression);
		Assert.notNull(aggregateCounterRepository, "Aggregate Counter Repository can not be null");
		Assert.notNull(incrementExpression, "Increment expression can not be null");
		this.aggregateCounterRepository = aggregateCounterRepository;
		this.incrementExpression = spelExpressionParser.parseExpression(incrementExpression);
	}

	public void setDateFormat(String pattern) {
		Assert.hasText(pattern, "dateFormat pattern must not be empty");
		this.dateFormat = DateTimeFormat.forPattern(pattern);
	}

	public Message<?> process(Message<?> message, String timeField) throws ParseException {
		if (message == null) {
			return null;
		}

		Double increment = incrementExpression.getValue(evaluationContext, message, Double.class);
		String counterName = computeMetricName(message);

		if (timeField == null) {
			this.aggregateCounterRepository.increment(counterName, increment.longValue());
		}
		else {
			this.aggregateCounterRepository.increment(counterName, increment.longValue(),
					dateFormat.parseDateTime(timeField));
		}
		return message;
	}

}