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IN PROGRESS - issue INT-656: MethodParameterMessageMapper - javadoc vs code

Browse Source 
http://jira.springframework.org/browse/INT-656

Improved javadoc
This commit is contained in:
Iwein Fuld
2009-06-11 19:53:16 +00:00
parent d7b9107c77
commit 23b1bd363e
1 changed files with 45 additions and 20 deletions
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65
org.springframework.integration/src/main/java/org/springframework/integration/message/MethodParameterMessageMapper.java
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@@ -38,17 +38,43 @@ import org.springframework.util.StringUtils;
/**
* Prepares arguments for handler methods. The method parameters are matched
* against the Message payload as well as its headers. If a method parameter is
* annotated with {@link Header @Header}, the annotation's value will be used as
* a header name. If such an annotation contains no value, then the parameter
* name will be used as long as the information is available in the class file
* (requires compilation with debug settings for parameter names). If the
* {@link Header @Header} annotation is not present, then the parameter will
* typically match the Message payload. However, if a Map or Properties object
* is expected, and the paylaod is not itself assignable to that type, then the
* MessageHeaders' values will be passed in the case of a Map-typed parameter,
* or the MessageHeaders' String-based values will be passed in the case of a
* Properties-typed parameter.
* against the Message, its payload as well as its headers. A message or payload
* parameter must not be annotated, there can be at most one of these. In
* certain special cases more than one unannotated parameters can be used (more
* on this later) but there should always be at most one parameter that the
* message or it's payload.
* <p/>
* If a method parameter is annotated with {@link Header @Header}, the
* annotation's value will be used as a header name. If such an annotation
* contains no value, then the parameter name will be used as long as the
* information is available in the class file (requires compilation with debug
* settings for parameter names). In addition a Map or Properties parameter can
* be matched to all the message headers. This can be done explicitly through
* the {@link Headers @Headers} annotation, or implicitly by using a non
* ambiguous method signature. There can be as many Header annotated parameters
* as the user wants. There needs to be only one Headers parameter.
* <p/>
* If a Map or Properties object is expected, and the payload is not itself
* assignable to that type, then the MessageHeaders' values will be passed in
* the case of a Map-typed parameter, or the MessageHeaders' String-based values
* will be passed in the case of a Properties-typed parameter. In these cases
* multiple unannotated parameters are legal.
* <p/>
* Some examples of legal method signatures:<br/>
* <tt>public void dealWith(Object payload);</tt><br/>
* <tt>public void dealWith(Message message);</tt><br/>
* <tt>public void dealWith(@Header String myHeader, Object payload);</tt><br/>
* <tt>public void dealWith(@Header String myHeader, @Header String anotherHeader);</tt>
* <br/>
* <tt>public void dealWith(@Headers Map headers, Object payload);</tt><br/>
* <tt>public void dealWith(@Headers Properties headers, Map payload);</tt><br/>
* <tt>public void dealWith(Properties headers, Object payload);</tt><br/>
* <p/>
* Some examples of illegal method signatures: <br/>
* <tt>public void dealWith(Object payload, String payload);</tt><br/>
* <tt>public void dealWith(Message message, Object payload);</tt><br/>
* <tt>public void dealWith(Properties headers, Map payload);</tt><br/>
*
*
* @author Mark Fisher
* @author Iwein Fuld
@@ -77,7 +103,8 @@ public class MethodParameterMessageMapper implements InboundMessageMapper<Object
if (metadata.getHeaderAnnotation() == null && !metadata.hasHeadersAnnotation()
&& !Message.class.isAssignableFrom(metadata.getParameterType())) {
payloadCandidates.add(metadata);
} else if (Message.class.isAssignableFrom(metadata.getParameterType())){
}
else if (Message.class.isAssignableFrom(metadata.getParameterType())) {
messagesFound++;
}
}
@@ -90,8 +117,9 @@ public class MethodParameterMessageMapper implements InboundMessageMapper<Object
}
}
}
Assert.isTrue(payloadCandidates.size()+messagesFound <= 1, "Could not find at most one message or payload parameter among ["
+ parameterMetadata + "] ended up with the candidates [" + payloadCandidates + "]");
Assert.isTrue(payloadCandidates.size() + messagesFound <= 1,
"Could not find at most one message or payload parameter among [" + parameterMetadata
+ "] ended up with the candidates [" + payloadCandidates + "]");
MethodParameterMetadata methodParameterMetadata = payloadCandidates.toArray(new MethodParameterMetadata[1])[0];
return methodParameterMetadata;
}
@@ -133,17 +161,14 @@ public class MethodParameterMessageMapper implements InboundMessageMapper<Object
Assert.isTrue(!required, "header '" + headerName + "' is required");
}
}
else if (metadata.hasHeadersAnnotation()) {
else if (metadata.hasHeadersAnnotation() || metadata.isMapOrProperties()) {
if (value != null) {
this.addHeadersAnnotatedParameterToMap(value, headers);
}
}
else if (metadata.getParameterType().equals(Message.class)) {
message = (Message<?>) value;
}
else {
Assert.isTrue(metadata.isMapOrProperties());
this.addHeadersAnnotatedParameterToMap(value, headers);
Assert.isTrue(Message.class.isAssignableFrom(metadata.getParameterType()));
message = (Message<?>) value;
}
}
if (message != null) {