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commit 8cc00547aacd91ff56890ced1a0fa60b43e54d85
Author: Claus Ibsen <claus.ib...@gmail.com>
AuthorDate: Sat Feb 6 13:03:29 2021 +0100
CAMEL-16102: Source code generate @InvokeOnHeader for reflection free
---
.../java/org/apache/camel/spi/InvokeOnHeader.java | 35 +++++++++++-----------
.../camel/support/HeaderSelectorProducer.java | 19 ++++++++++--
2 files changed, 34 insertions(+), 20 deletions(-)
diff --git
a/core/camel-api/src/main/java/org/apache/camel/spi/InvokeOnHeader.java
b/core/camel-api/src/main/java/org/apache/camel/spi/InvokeOnHeader.java
index 55008ce..57cf986 100644
--- a/core/camel-api/src/main/java/org/apache/camel/spi/InvokeOnHeader.java
+++ b/core/camel-api/src/main/java/org/apache/camel/spi/InvokeOnHeader.java
@@ -27,22 +27,25 @@ import org.apache.camel.Message;
/**
* Marks a method as being invoked for a specific header value.
* <p/>
- * The method must have either of the following method signatures:
- *
- * <pre>
- * void theMethodName(Message message) throws Exception;
- *
- * Object theMethodName(Message message) throws Exception;
- *
- * boolean theMethodName(Message message, AsyncCallback callback) throws
Exception;
- * </pre>
- *
- * If the method includes the {@link AsyncCallback} type, then the return
value must be boolean, as part of the async
- * callback contract. Throwing exceptions is optional and can be omitted.
+ * The method can either be executed synchronously or asynchronously (with
{@link AsyncCallback}.
* <p/>
- * This can be used by Component implementations that uses
org.apache.camel.support.HeaderSelectorProducer.
- *
- * This requires to use Camel maven tooling (camel-package-maven-plugin) to
generate java source code
+ * A method is only asynchronously executed if the method has {@link
AsyncCallback} as a parameter.
+ * In this situation then the method should not return a value (void). And its
the responsible
+ * of the method to invoke <pre>callback.done(false)</pre> when to continue
routing.
+ * <p/>
+ * Synchronous methods can either be void or return a value. If a value is
returned then the value
+ * will be set as the response body.
+ * <p/>
+ * The method accepts the following parameters:
+ * <ul>
+ * <li>Exchange - the current exchange</li>
+ * <li>Message - the current message</li>
+ * <li>CamelContext - the camel context</li>
+ * <li>AsyncCallback - for asynchronous processing</li>
+ * <li>Object - Object or any other type is regarded as the current
message body, converted to the given type</li>
+ * </ul>
+ * Component implementation producers should extend
org.apache.camel.support.HeaderSelectorProducer.
+ * And use Camel maven tooling (camel-package-maven-plugin) to generate java
source code
* that selects and invokes the method at runtime.
*
* @see Message#getHeader(String)
@@ -51,8 +54,6 @@ import org.apache.camel.Message;
@Target(ElementType.METHOD)
public @interface InvokeOnHeader {
- // TODO: Update javadoc as parameter binding has improved
-
/**
* Name of header.
*/
diff --git
a/core/camel-support/src/main/java/org/apache/camel/support/HeaderSelectorProducer.java
b/core/camel-support/src/main/java/org/apache/camel/support/HeaderSelectorProducer.java
index 96e8bc3..ffe21ca 100644
---
a/core/camel-support/src/main/java/org/apache/camel/support/HeaderSelectorProducer.java
+++
b/core/camel-support/src/main/java/org/apache/camel/support/HeaderSelectorProducer.java
@@ -32,6 +32,9 @@ import org.slf4j.LoggerFactory;
/**
* A selector-based producer which uses a header value to determine which
processor should be invoked.
+ *
+ * @see org.apache.camel.spi.InvokeOnHeader
+ * @see InvokeOnHeaderStrategy
*/
public abstract class HeaderSelectorProducer extends DefaultAsyncProducer
implements CamelContextAware {
@@ -186,12 +189,10 @@ public abstract class HeaderSelectorProducer extends
DefaultAsyncProducer implem
}
if (sync) {
LOGGER.trace("Invoked @InvokeOnHeader method: {} -> {}",
action, answer);
+ processResult(exchange, answer);
} else {
LOGGER.trace("Invoked @InvokeOnHeader method: {} is continuing
asynchronously", action);
}
- if (answer != null) {
- exchange.getMessage().setBody(answer);
- }
} catch (Exception e) {
exchange.setException(e);
}
@@ -203,4 +204,16 @@ public abstract class HeaderSelectorProducer extends
DefaultAsyncProducer implem
return sync;
}
+ /**
+ * Process the result. Will by default set the result as the message body.
+ *
+ * @param exchange the exchange
+ * @param result the result (may be null)
+ */
+ protected void processResult(Exchange exchange, Object result) {
+ if (result != null) {
+ exchange.getMessage().setBody(result);
+ }
+ }
+
}
