org.cleverbus.api.common.ExchangeHelper.java Source code

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Here is the source code for org.cleverbus.api.common.ExchangeHelper.java

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/*
 * 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.api.common;

import static org.cleverbus.api.common.ExchangeConstants.TRACE_HEADER;

import javax.annotation.Nullable;

import org.cleverbus.api.asynch.model.TraceHeader;
import org.cleverbus.api.exception.IllegalDataException;

import org.apache.camel.Exchange;
import org.apache.camel.Message;
import org.springframework.util.Assert;

/**
 * Some helper methods for working with {@link Exchange} objects.
 *
 * @author <a href="mailto:tomas.hanus@cleverlance.com">Tomas Hanus</a>
 * @since 0.4
 */
public final class ExchangeHelper {

    /**
     * Returns the {@link TraceHeader} or throws an {@link IllegalDataException} if it is not present and is mandatory.
     * @param exchange the exchange message
     * @param mandatory true if trace header is mandatory output
     * @return the {@link TraceHeader} object as header value from exchange
     */
    @Nullable
    public static TraceHeader getTraceHeader(Exchange exchange, boolean mandatory) {
        Assert.notNull(exchange, "the exchange must not be null");

        TraceHeader answer = exchange.getIn().getHeader(TRACE_HEADER, TraceHeader.class);

        if (mandatory) {
            Constraints.notNull(answer, "TraceHeader is mandatory and is not included in this exchange.");
        }
        return answer;
    }

    /**
     * Propagates (copies) the {@code Body}, the {@code Attachments} and the {@code Headers} of the {@link Message}
     * from from IN to OUT.
     *
     * @param exchange the exchange message
     */
    public static void propagateMessage(Exchange exchange) {
        Assert.notNull(exchange, "the exchange must not be null");

        // copy headers from IN to OUT to propagate them
        exchange.getOut().setHeaders(exchange.getIn().getHeaders());
        // copy attachments from IN to OUT to propagate them
        exchange.getOut().setAttachments(exchange.getIn().getAttachments());
        // copy body from IN to OUT to propagate it
        exchange.getOut().setBody(exchange.getIn().getBody());
    }

    /**
     * Utility classes should not have a public constructor.
     */
    private ExchangeHelper() {
    }
}