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For example a simple route can be created as follows.

Code Block
languagejava
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        errorHandler(deadLetterChannel("mock:error"));


        from("direct:a").to("direct:b");
    }
};
Wiki Markup
{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}


As you can see from the above Camel uses URIs to wire endpoints together.

...

If you have endpoint URIs that accept options and you want to be able to substitute the value, e.g. build the URI by concat the strings together, then you can use the java.lang.String.format method. But in Camel 2.0 we have added two convenient methods in the Java DSL so you can do fromF and toF that uses String formatting to build the URI.

Code Block
languagejava
from("direct:start").toF("file://%s?fileName=%s", path, name);

fromF("file://%s?include=%s", path, pattern).toF("mock:%s", result);
Wiki Markup
{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/RouteFormattedUriTest.java}

Filters

You can combine simple routes with filters which can be arbitrary Predicate implementations.

Code Block
languagejava
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        errorHandler(deadLetterChannel("mock:error"));

        from("direct:a")
            .filter(header("foo").isEqualTo("bar"))
                .to("direct:b");
    }
};
Wiki Markup
{snippet:id=e2|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}

Choices

With a choice you provide a list of predicates and outcomes along with an optional default otherwise clause which is invoked if none of the conditions are met.

Code Block
languagejava
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        errorHandler(deadLetterChannel("mock:error"));

        from("direct:a")
            .choice()
                .when(header("foo").isEqualTo("bar"))
                    .to("direct:b")
                .when(header("foo").isEqualTo("cheese"))
                    .to("direct:c")
                .otherwise()
                    .to("direct:d");
    }
};
Wiki Markup
{snippet:id=e3|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}

Using a custom processor

Here is an example of using a custom Processor

Code Block
languagejava
myProcessor = new Processor() {
    public void process(Exchange exchange) {
        log.debug("Called with exchange: " + exchange);
    }
};

RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        errorHandler(deadLetterChannel("mock:error"));

        from("direct:a")
            .process(myProcessor);
    }
};
Wiki Markup
{snippet:id=e4|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}


You can mix and match custom processors with filters and choices.

Wiki Markup
{snippet:id=e5|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}

Interceptors

Here is an example of adding a few custom InterceptorProcessor objects to a processing pipeline:

Wiki Markup
{snippet:id=e7|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/builder/RouteBuilderTest.java}

...

Code Block
languagejava
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
        errorHandler(deadLetterChannel("mock:error"));

        from("direct:a")
            .filter(header("foo").isEqualTo("bar"))
                .process(myProcessor);
    }
};