ExternalCallProducer.java

/*
 * Copyright (C) 2015
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.cleverbus.component.externalcall;

import static org.apache.commons.lang.BooleanUtils.isNotTrue;
import static org.springframework.util.StringUtils.hasText;

import org.cleverbus.api.asynch.AsynchConstants;
import org.cleverbus.api.entity.ExternalCall;
import org.cleverbus.api.entity.Message;
import org.cleverbus.api.exception.LockFailureException;
import org.cleverbus.api.extcall.ExtCallComponentParams;
import org.cleverbus.common.log.Log;
import org.cleverbus.spi.extcall.ExternalCallService;

import org.apache.camel.Exchange;
import org.apache.camel.impl.DefaultProducer;
import org.springframework.util.Assert;


/**
 * See {@link ExternalCallComponent}
 */
public class ExternalCallProducer extends DefaultProducer {

    public ExternalCallProducer(ExternalCallEndpoint externalCallEndpoint) {
        super(externalCallEndpoint);
    }

    @Override
    public void process(final Exchange exchange) throws Exception {
        Message message = getMessage(exchange);
        String targetURI = getTargetURI(exchange);
        String operation = getOperation(exchange);
        String key = getOperationKey(exchange);
        ExternalCallService service = getService(exchange);

        Log.debug("External call check: operation URI = {}, operation key = {}, msgTimestamp = {}",
                operation, key, message.getMsgTimestamp());

        ExternalCall externalCall = prepareExternalCall(operation, key, message, service);
        if (externalCall != null) {
            try {
                executeExternalCall(exchange, targetURI);
            } finally {
                finalizeExternalCall(exchange, externalCall, service); // in either case release the external call
            }
        } else {
            Log.debug("External call was skipped. See external call service log for detailed info. " +
                    "Call: target={} operation={} key={} msgId={} msgTimestamp={}",
                    targetURI, operation, key, message.getMsgId(), message.getMsgTimestamp());
        }
    }

    protected ExternalCall prepareExternalCall(
            String operation, String key, Message message, ExternalCallService service) {
        try {
            return service.prepare(operation, key, message);
        } catch (LockFailureException exc) {
            throw exc; // don't re-wrap lock failure
        } catch (Exception exc) {
            throw new LockFailureException(String.format(
                    "External call lock failure, please retry. " +
                            "Call: operation=%s key=%s msgId=%s msgTimestamp=%s",
                    operation, key, message.getMsgId(), message.getMsgTimestamp()), exc);
        }
    }

    protected void executeExternalCall(Exchange exchange, String targetURI) {
        try {
            // success should not be determined before the call is made
            exchange.removeProperty(ExtCallComponentParams.EXTERNAL_CALL_SUCCESS);
            // route exchange to external call target
            getEndpoint().getProducerTemplate().send(targetURI, exchange);
        } catch (Exception exc) {
            exchange.setException(exc); // this also marks exchange as failed
        }
    }

    protected void finalizeExternalCall(Exchange exchange, ExternalCall externalCall, ExternalCallService service) {
        Boolean success = exchange.getProperty(ExtCallComponentParams.EXTERNAL_CALL_SUCCESS, Boolean.class);
        if (success == null) {
            // success is not defined forcefully -> determine success normally
            success = !exchange.isFailed()
                    && isNotTrue(exchange.getProperty(Exchange.ROUTE_STOP, Boolean.class));
        }
        if (success) {
            service.complete(externalCall);
        } else {
            service.failed(externalCall);
        }
        // cleanup:
        exchange.removeProperty(ExtCallComponentParams.EXTERNAL_CALL_OPERATION);
        exchange.removeProperty(ExtCallComponentParams.EXTERNAL_CALL_KEY);
        exchange.removeProperty(ExtCallComponentParams.EXTERNAL_CALL_SUCCESS);
    }

    protected Message getMessage(Exchange exchange) {
        Message message = exchange.getIn().getHeader(AsynchConstants.MSG_HEADER, Message.class);
        Assert.notNull(message, "Message must be provided in header '" + AsynchConstants.MSG_HEADER + "'");
        return message;
    }

    protected String getTargetURI(Exchange exchange) {
        return getEndpoint().getTargetURI();
    }

    protected String getOperation(Exchange exchange) {
        String operation = exchange.getProperty(ExtCallComponentParams.EXTERNAL_CALL_OPERATION, String.class);
        return hasText(operation) ? operation : getTargetURI(exchange);
    }

    protected String getOperationKey(Exchange exchange) {
        return getEndpoint().getKeyType().getExpression().evaluate(exchange, Object.class).toString();
    }

    protected ExternalCallService getService(Exchange exchange) {
        return getEndpoint().getService();
    }

    @Override
    public ExternalCallEndpoint getEndpoint() {
        return (ExternalCallEndpoint) super.getEndpoint();
    }
}