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https://issues.apache.org/jira/browse/CAMEL-20889?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17855900#comment-17855900
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Claus Ibsen commented on CAMEL-20889:
-------------------------------------
See the documentation
{code:java}
/**
* Returns the body as the specified type
* <p/>
* Notice if the message body is stream based then calling this method multiple
times may lead to the stream not
* being able to be re-read again. You can enable stream caching and call the
{@link StreamCache#reset()} method to
* reset the stream to be able to re-read again (if possible). See more details
about
* <a href="http://camel.apache.org/stream-caching.html";>stream caching</a>.
*
* @param type the type that the body
* @return the body of the message as the specified
type, or <tt>null</tt> if no body exists
* @throws TypeConversionException is thrown if error during type conversion
*/
<T> T getBody(Class<T> type);
{code}
> camel-core: Stream is not reset when Message.getBody(class) is invoked ans
> stream caching is enabled
> ----------------------------------------------------------------------------------------------------
>
> Key: CAMEL-20889
> URL: https://issues.apache.org/jira/browse/CAMEL-20889
> Project: Camel
> Issue Type: Bug
> Components: came-core
> Reporter: Luigi De Masi
> Assignee: Luigi De Masi
> Priority: Major
>
> Having the following Camel route on Camel 2.x
> {code:java}
> from("timer:mytimer2?repeatCount=1&delay=1000")
> .routeId("generate-route-marshall")
> .streamCaching()
> .transform(constant("\{\"maskme\":\"json payload\"}"))
> .marshal().json(JsonLibrary.Jackson)
> .process(exchange ->
> {
> LOGGER.info("body class name -> " +
> exchange.getIn().getBody().getClass().getName());
> LOGGER.info("consumed once using .getBody(String.class) -> " +
> exchange.getIn().getBody(String.class));
> LOGGER.info("consumed twice using .getBody(String.class) -> " +
> exchange.getIn().getBody(String.class));
> })
> .to("jms:queue:INCOMING");
> {code}
>
> Shows that the consumption of the message payload in the processor via
> {code:java}
> exchange.getIn().getBody(String.class));\{code}
> works as expected, as the body is shown twice on the logs, as follows.
> {code:java}
> body class name -> org.apache.camel.converter.stream.InputStreamCache
> consumed once using .getBody(String.class) -> "\{\"maskme\":\"json
> payload\"}"
> consumed twice using .getBody(String.class) -> "\{\"maskme\":\"json
> payload\"}"
> {code}
>
> But if you run this same route from Camel 3.x to the latest 4.x one, you
> will get the following output:
> {code:java}
> body class name -> org.apache.camel.converter.stream.InputStreamCache
> consumed once using .getBody(String.class) -> "\{\"maskme\":\"json
> payload\"}"
> consumed once using .getBody(String.class) ->
> {code}
>
> The problem is that on Camel 2.x, when
> {{ exchange.getIn().getBody(String.class))}}
> is called, the
> [org.apache.camel.converter.IOConverterOptimised|https://github.com/apache/camel/blob/camel-2.x/camel-core/src/main/java/org/apache/camel/converter/IOConverterOptimised.java]
> is triggered to convert the body from
> {{org.apache.camel.converter.stream.InputStreamCache}} to
> {{{}java.lang.String{}}}, which at the beginning of the convertion, [it reset
> the
> stream|https://github.com/apache/camel/blob/a05826ece32fbb8e2ba6df0e0ac2a3d5903f9572/camel-core/src/main/java/org/apache/camel/converter/IOConverterOptimised.java#L50]:
>
> {code:java|title=IOConverterOptimised.java}
> public final class IOConverterOptimised {
> private IOConverterOptimised() {
> }
> public static Object convertTo(final Class<?> type, final Exchange
> exchange, final Object value) throws Exception {
> Class fromType = value.getClass();
> if (value instanceof StreamCache) {
> ((StreamCache)value).reset(); // <------ HERE
> }
> {code}
> From Camel 3.x,
> [org.apache.camel.converter.IOConverterOptimised|https://github.com/apache/camel/blob/camel-2.x/camel-core/src/main/java/org/apache/camel/converter/IOConverterOptimised.java]
> has been dropped, and
> [org.apache.camel.converter.IOConverter|https://github.com/apache/camel/blob/4c41ebcb73af761dcebf6e4ebb9a68e768e505a1/core/camel-base/src/main/java/org/apache/camel/converter/IOConverter.java]
> is used instead, which doesn't reset the stream.
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