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new ec6c5c8706f9 CAMEL-22935: Add docs
ec6c5c8706f9 is described below
commit ec6c5c8706f905c6819773751c2168a2a8781adb
Author: Claus Ibsen <[email protected]>
AuthorDate: Mon Feb 2 11:38:18 2026 +0100
CAMEL-22935: Add docs
---
.../modules/languages/pages/simple-language.adoc | 57 ++++++++++++++++++++++
.../language/simple/SimpleCustomFunctionTest.java | 38 +++++++++++++--
2 files changed, 92 insertions(+), 3 deletions(-)
diff --git
a/core/camel-core-languages/src/main/docs/modules/languages/pages/simple-language.adoc
b/core/camel-core-languages/src/main/docs/modules/languages/pages/simple-language.adoc
index 4a37b75a3a00..85550e46aaac 100644
---
a/core/camel-core-languages/src/main/docs/modules/languages/pages/simple-language.adoc
+++
b/core/camel-core-languages/src/main/docs/modules/languages/pages/simple-language.adoc
@@ -1823,6 +1823,63 @@ And in XML DSL you use the pretty attribute to true as
show below:
</route>
----
+== Adding custom functions to Simple language
+
+You can add custom functions to the Simple language by adding to the
`org.apache.camel.spi.SimpleFunctionRegistry`.
+
+This can be done programmatically such as:
+
+[source,java]
+----
+SimpleFunctionRegistry reg =
PluginHelper.getSimpleFunctionRegistry(getCamelContext());
+
+reg.addFunction("foo", new ExpressionAdapter() {
+ @Override
+ public Object evaluate(Exchange exchange) {
+ return "I was here " + exchange.getMessage().getBody();
+ }
+});
+----
+
+Here we add a custom function named `foo` which is implemented as a
`org.apache.camel.Expression` which conveniently
+can be done by using the `org.apache.camel.support.ExpressionAdapter` class as
above.
+
+The foo function can now be used in simple such as:
+
+[source,java]
+----
+from("direct:start2")
+ .setBody(simple("Hello ${foo}"))
+ .to("mock:result");
+----
+
+Notice how the foo function is used just like it was a built-in function using
`$\{foo}` syntax.
+
+Since a custom function is just an `Expression` then it's possible to build
custom functions from
+all the Camel languages such as Groovy, JSonPath and even Simple as well.
+
+[source,java]
+----
+var bar = context.resolveLanguage("simple").createExpression("${trim()} ~>
${normalizeWhitespace()} ~> ${capitalize()} ~> ${quote()}");
+reg.addFunction("bar", bar);
+----
+
+The `bar` function is build using simple functions using the `~>` chain
operators to perform a sequence of functions on the payload.
+
+Custom functions will by default use the message body as the payload. But they
also support a single parameter as the input,
+which allows to provide the input as fixed value such as a string literal or
to refer to an existing header or variable.
+
+For example the foo function uses variable with name `msg` as the input:
+
+[source,java]
+----
+from("direct:start")
+ .setVariable("msg", constant("Moon"))
+ .setBody(simple("Bye ${foo(${variable.msg})}"))
+ .to("mock:result");
+----
+
+
== Dependencies
The Simple language is part of *camel-core*.
diff --git
a/core/camel-core/src/test/java/org/apache/camel/language/simple/SimpleCustomFunctionTest.java
b/core/camel-core/src/test/java/org/apache/camel/language/simple/SimpleCustomFunctionTest.java
index 25dfd64850e7..bbb1ba01cac6 100644
---
a/core/camel-core/src/test/java/org/apache/camel/language/simple/SimpleCustomFunctionTest.java
+++
b/core/camel-core/src/test/java/org/apache/camel/language/simple/SimpleCustomFunctionTest.java
@@ -31,20 +31,40 @@ public class SimpleCustomFunctionTest extends
ContextTestSupport {
@Test
public void testCustomFunctionWithBody() throws Exception {
SimpleFunctionRegistry reg =
PluginHelper.getSimpleFunctionRegistry(context);
- Assertions.assertEquals(1, reg.customSize());
+ Assertions.assertEquals(2, reg.customSize());
getMockEndpoint("mock:result").expectedBodiesReceived("Hello I was
here World");
template.sendBody("direct:start", "World");
assertMockEndpointsSatisfied();
}
+ @Test
+ public void testCustomFunctionWithBodyFunction() throws Exception {
+ SimpleFunctionRegistry reg =
PluginHelper.getSimpleFunctionRegistry(context);
+ Assertions.assertEquals(2, reg.customSize());
+
+ getMockEndpoint("mock:result").expectedBodiesReceived("Hello I was
here Earth");
+ template.sendBody("direct:start2", "Earth");
+ assertMockEndpointsSatisfied();
+ }
+
@Test
public void testCustomFunctionWithExp() throws Exception {
SimpleFunctionRegistry reg =
PluginHelper.getSimpleFunctionRegistry(context);
- Assertions.assertEquals(1, reg.customSize());
+ Assertions.assertEquals(2, reg.customSize());
getMockEndpoint("mock:result").expectedBodiesReceived("Bye I was here
Moon");
- template.sendBody("direct:start2", "World");
+ template.sendBody("direct:start3", "World");
+ assertMockEndpointsSatisfied();
+ }
+
+ @Test
+ public void testCustomFunctionWithSimple() throws Exception {
+ SimpleFunctionRegistry reg =
PluginHelper.getSimpleFunctionRegistry(context);
+ Assertions.assertEquals(2, reg.customSize());
+
+ getMockEndpoint("mock:result").expectedBodiesReceived("\"Hello World I
Was Here\"");
+ template.sendBody("direct:start4", " hello world i was here ");
assertMockEndpointsSatisfied();
}
@@ -61,14 +81,26 @@ public class SimpleCustomFunctionTest extends
ContextTestSupport {
}
});
+ var bar = context.resolveLanguage("simple")
+ .createExpression("${trim()} ~>
${normalizeWhitespace()} ~> ${capitalize()} ~> ${quote()}");
+ reg.addFunction("bar", bar);
+
from("direct:start")
.setBody(simple("Hello ${function(foo)}"))
.to("mock:result");
from("direct:start2")
+ .setBody(simple("Hello ${foo}"))
+ .to("mock:result");
+
+ from("direct:start3")
.setVariable("msg", constant("Moon"))
.setBody(simple("Bye
${function(foo,${variable.msg})}"))
.to("mock:result");
+
+ from("direct:start4")
+ .setBody(simple("${bar}"))
+ .to("mock:result");
}
};
}
