Modified: websites/production/camel/content/wire-tap.html
==============================================================================
--- websites/production/camel/content/wire-tap.html (original)
+++ websites/production/camel/content/wire-tap.html Fri Aug 25 08:22:01 2017
@@ -36,17 +36,6 @@
<![endif]-->
- <link href='//camel.apache.org/styles/highlighter/styles/shCoreCamel.css'
rel='stylesheet' type='text/css' />
- <link href='//camel.apache.org/styles/highlighter/styles/shThemeCamel.css'
rel='stylesheet' type='text/css' />
- <script src='//camel.apache.org/styles/highlighter/scripts/shCore.js'
type='text/javascript'></script>
- <script src='//camel.apache.org/styles/highlighter/scripts/shBrushJava.js'
type='text/javascript'></script>
- <script src='//camel.apache.org/styles/highlighter/scripts/shBrushXml.js'
type='text/javascript'></script>
- <script src='//camel.apache.org/styles/highlighter/scripts/shBrushPlain.js'
type='text/javascript'></script>
-
- <script type="text/javascript">
- SyntaxHighlighter.defaults['toolbar'] = false;
- SyntaxHighlighter.all();
- </script>
<title>
Apache Camel: Wire Tap
@@ -86,112 +75,9 @@
<tbody>
<tr>
<td valign="top" width="100%">
-<div class="wiki-content maincontent"><h3 id="WireTap-WireTap">Wire
Tap</h3><p><a shape="rect" class="external-link"
href="http://www.enterpriseintegrationpatterns.com/WireTap.html";
rel="nofollow">Wire Tap</a> (from the <a shape="rect"
href="enterprise-integration-patterns.html">EIP patterns</a>) allows you to
route messages to a separate location while they are being forwarded to the
ultimate destination.</p><p><span class="confluence-embedded-file-wrapper"><img
class="confluence-embedded-image confluence-external-resource"
src="http://www.enterpriseintegrationpatterns.com/img/WireTap.gif";
data-image-src="http://www.enterpriseintegrationpatterns.com/img/WireTap.gif";></span></p><div
class="confluence-information-macro
confluence-information-macro-information"><p class="title">Streams</p><span
class="aui-icon aui-icon-small aui-iconfont-info
confluence-information-macro-icon"></span><div
class="confluence-information-macro-body"><p>If you <a shape="rect"
href="wire-tap.html">Wire Tap
</a> a stream message body then you should consider enabling <a shape="rect"
href="stream-caching.html">Stream caching</a> to ensure the message body can be
read at each endpoint. See more details at <a shape="rect"
href="stream-caching.html">Stream caching</a>.</p></div></div><h3
id="WireTap-Options">Options</h3><div class="table-wrap"><table
class="confluenceTable"><tbody><tr><th colspan="1" rowspan="1"
class="confluenceTh">Name</th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>uri</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong><span style="color:
rgb(255,0,0);">Mandatory</span>:</strong> The URI of the endpoint to which the
wire-tapped message should be sent.</p><p>From <strong>Camel 2.16</strong>:
support for dynamic <stro
ng><code>to</code></strong> URIs is as documented in <a shape="rect"
class="external-link" href="http://camel.apache.org/message-endpoint.html";
style="line-height: 1.4285715;">Message Endpoint.</a></p></td></tr><tr><td
colspan="1" rowspan="1"
class="confluenceTd"><p><code>executorServiceRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Reference ID of a custom <a shape="rect"
href="threading-model.html">Thread Pool</a> to use when processing the
wire-tapped messages.</p><p>When not set, Camel will use an instance of the
default thread pool.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>processorRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Reference ID of a custom <a shape="rect"
href="processor.html">Processor</a> to use for creating a new
message.</p><p>See "<strong>Sending a
New Exchange</strong>" below.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>copy</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>true</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>Camel 2.3</strong>: Whether to copy the <a
shape="rect" href="exchange.html">Exchange</a> before wire-tapping the
message.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>onPrepareRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>Camel 2.8:</strong> Reference identifier of a
custom <a shape="rect" href="processor.html">Processor</a> to prepare the copy
of the <a shape="rect" href="exchange.html">Exchange</a> to be wire-tapped.
This allows you to do any custom logic, such as deep-cloning the message
payload.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>cacheSize</code></p></
td><td colspan="1" rowspan="1" class="confluenceTd"> </td><td colspan="1"
rowspan="1" class="confluenceTd"><p><span style="color:
rgb(0,0,0);"><strong>Camel 2.16:</strong> Allows to configure the cache size
for the </span><strong><code>ProducerCache</code></strong><span
style="color: rgb(0,0,0);"> which caches producers for reuse. Will by
default use the default cache size which is <strong><code>1000</code></strong>.
</span></p><p><span style="color: rgb(0,0,0);">Setting the value
to <strong><code>-1</code></strong> allows to turn off the cache all
together.</span></p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>ignoreInvalidEndpoint</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.16:</strong>
<span style="color: rgb(0,0,0);">Whether to ignore an endpoint URI that could
not be resolved. </span></p><p><span style="color: rgb(
0,0,0);">When <strong><code>false</code></strong>, Camel will throw an
exception when it identifies an invalid endpoint
URI.</span></p></td></tr></tbody></table></div><h3
id="WireTap-WireTapThreadpool">WireTap Threadpool</h3><p>The <a shape="rect"
href="wire-tap.html">Wire Tap</a> uses a thread pool to process the tapped
messages. This thread pool will by default use the settings detailed at <a
shape="rect" href="threading-model.html">Threading Model</a>. In particular,
when the pool is exhausted (with all threads utilized), further wiretaps will
be executed synchronously by the calling thread. To remedy this, you can
configure an explicit thread pool on the <a shape="rect"
href="wire-tap.html">Wire Tap</a> having either a different rejection policy, a
larger worker queue, or more worker threads.</p><h3
id="WireTap-WireTapNode">WireTap Node</h3><p>Camel's Wire Tap node supports two
flavors when tapping an <a shape="rect"
href="exchange.html">Exchange</a>:</p><ul><li>With the traditi
onal Wire Tap, Camel will copy the original <a shape="rect"
href="exchange.html">Exchange</a> and set its <a shape="rect"
href="exchange-pattern.html">Exchange Pattern</a> to
<strong><code>InOnly</code></strong>, as we want the tapped <a shape="rect"
href="exchange.html">Exchange</a> to be sent in a fire and forget style. The
tapped <a shape="rect" href="exchange.html">Exchange</a> is then sent in a
separate thread so it can run in parallel with the original. Beware that only
the Exchange is copied - Wire Tap won't do a deep clone (unless you specify a
custom processor via <strong><code>onPrepareRef</code></strong> which does
that). So all copies could share objects from the original
Exchange.</li><li>Camel also provides an option of sending a new <a
shape="rect" href="exchange.html">Exchange</a> allowing you to populate it with
new values.</li></ul><h4 id="WireTap-SendingaCopy(traditionalwiretap)">Sending
a Copy (traditional wiretap)</h4><p><strong>Using the <a shape="rect" hr
ef="fluent-builders.html">Fluent Builders</a></strong></p><div class="code
panel pdl" style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-from("direct:start")
- .to("log:foo")
- .wireTap("direct:tap")
- .to("mock:result");
-]]></script>
-</div></div><strong>Using the <a shape="rect"
href="spring-xml-extensions.html">Spring XML Extensions</a></strong><div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-<route>
- <from uri="direct:start"/>
- <to uri="log:foo"/>
- <wireTap uri="direct:tap"/>
- <to uri="mock:result"/>
-</route>
-]]></script>
-</div></div><h4 id="WireTap-SendingaNew">Sending a New <a shape="rect"
href="exchange.html">Exchange</a></h4><p><strong>Using the <a shape="rect"
href="fluent-builders.html">Fluent Builders</a></strong><br clear="none"> Camel
supports either a processor or an <a shape="rect"
href="expression.html">Expression</a> to populate the new <a shape="rect"
href="exchange.html">Exchange</a>. Using a processor gives you full power over
how the <a shape="rect" href="exchange.html">Exchange</a> is populated as you
can set properties, headers, etc. An <a shape="rect"
href="expression.html">Expression</a> can only be used to set
the <strong><code>IN</code></strong> body.</p><p>From <strong>Camel
2.3</strong>: the <a shape="rect" href="expression.html">Expression</a> or <a
shape="rect" href="processor.html">Processor</a> is pre-populated with a copy
of the original <a shape="rect" href="exchange.html">Exchange</a>, which allows
you to access the original message when you prepare a new <a shape
="rect" href="exchange.html">Exchange</a> to be sent. You can use the
<strong><code>copy</code></strong> option (enabled by default) to indicate
whether you want this. If you set <strong><code>copy=false</code></strong>,
then it works as in <strong>Camel 2.2</strong> or older where the <a
shape="rect" href="exchange.html">Exchange</a> will be empty.</p><p>Below is
the processor variation. This example is from <strong>Camel 2.3</strong>, where
we disable <strong><code>copy</code></strong> by passing in
<strong><code>false</code></strong> to create a new, empty <a shape="rect"
href="exchange.html">Exchange</a>.</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-from("direct:start")
- .wireTap("direct:foo", false, new Processor() {
- public void process(Exchange exchange) throws Exception {
- exchange.getIn().setBody("Bye World");
- exchange.getIn().setHeader("foo", "bar");
- }
- }).to("mock:result");
-
-
-from("direct:foo").to("mock:foo");
-]]></script>
-</div></div>Here is the <a shape="rect" href="expression.html">Expression</a>
variation. In the following example we disable copying by setting
<strong><code>copy</code><code>=false</code></strong> which results in the
creation of a new, empty <a shape="rect" href="exchange.html">Exchange</a>.<div
class="code panel pdl" style="border-width: 1px;"><div class="codeContent
panelContent pdl">
-<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-from("direct:start")
- .wireTap("direct:foo", false, constant("Bye World"))
- .to("mock:result");
-
-from("direct:foo").to("mock:foo");
-]]></script>
-</div></div><strong>Using the <a shape="rect"
href="spring-xml-extensions.html">Spring XML Extensions</a></strong><br
clear="none"> The processor variation, which uses
a <strong><code>processorRef</code></strong> attribute to refer to a
Spring bean by ID:<div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
-<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-<route>
- <from uri="direct:start2"/>
- <wireTap uri="direct:foo"
processorRef="myProcessor"/>
- <to uri="mock:result"/>
-</route>
-]]></script>
-</div></div>Here is the <a shape="rect" href="expression.html">Expression</a>
variation, where the expression is defined in
the <strong><code>body</code></strong> tag:<div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-<route>
- <from uri="direct:start"/>
- <wireTap uri="direct:foo">
- <body><constant>Bye World</constant></body>
- </wireTap>
- <to uri="mock:result"/>
-</route>
-]]></script>
-</div></div>This variation accesses the body of the original message and
creates a new <a shape="rect" href="exchange.html">Exchange</a> based on the <a
shape="rect" href="expression.html">Expression</a>. It will create a new
Exchange and have the body contain <code>"<strong>Bye ORIGINAL BODY MESSAGE
HERE</strong>"</code><div class="code panel pdl" style="border-width:
1px;"><div class="codeContent panelContent pdl">
-<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-<route>
- <from uri="direct:start"/>
- <wireTap uri="direct:foo">
- <body><simple>Bye ${body}</simple></body>
- </wireTap>
- <to uri="mock:result"/>
-</route>
-]]></script>
-</div></div><h4 id="WireTap-FurtherExample">Further Example</h4><p>For another
example of this pattern, refer to the <a shape="rect" class="external-link"
href="http://svn.apache.org/repos/asf/camel/trunk/camel-core/src/test/java/org/apache/camel/processor/WireTapTest.java";>wire
tap test case</a>.</p><h3 id="WireTap-UsingDynamicURIs">Using Dynamic
URIs</h3><p><strong>Available as of Camel 2.16:</strong></p><p>For example to
wire tap to a dynamic URI, then it supports the same dynamic URIs as documented
in <a shape="rect" href="message-endpoint.html">Message Endpoint</a>. For
example to wire tap to a JMS queue where the header ID is part of the queue
name:</p><div class="code panel pdl" style="border-width: 1px;"><div
class="codeContent panelContent pdl">
-<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[from("direct:start")
- .wireTap("jms:queue:backup-${header.id}")
- .to("bean:doSomething");]]></script>
-</div></div><p> </p><h3
id="WireTap-SendingaNewandSetHeadersinDSL">Sending a New <a shape="rect"
href="exchange.html">Exchange</a> and Set Headers in
DSL</h3><p><strong>Available as of Camel 2.8</strong></p><p>If you send a new
message using <a shape="rect" href="wire-tap.html">Wire Tap</a>, then you could
only set the message body using an <a shape="rect"
href="expression.html">Expression</a> from the DSL. If you also need to set
headers, you would have to use a <a shape="rect"
href="processor.html">Processor</a>. From <strong>Camel 2.8</strong>: it's
possible to set headers as well using the DSL.</p><p>The following example
sends a new message which has</p><ul class="alternate"><li><strong><code>Bye
World</code></strong> as message body.</li><li>A header with
key <strong><code>id</code></strong> with the value
<strong><code>123</code></strong>.</li><li>A header with
key <strong><code>date</code></strong> which has current date as
value.</li></ul><h4 id="WireTap-Java
DSL">Java DSL</h4><p></p><div class="code panel pdl" style="border-width:
1px;"><div class="codeContent panelContent pdl">
-<script class="brush: java; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-from("direct:start")
- // tap a new message and send it to direct:tap
- // the new message should be Bye World with 2 headers
- .wireTap("direct:tap")
- // create the new tap message body and headers
- .newExchangeBody(constant("Bye World"))
- .newExchangeHeader("id", constant(123))
- .newExchangeHeader("date",
simple("${date:now:yyyyMMdd}"))
- .end()
- // here we continue routing the original messages
- .to("mock:result");
-
-// this is the tapped route
-from("direct:tap")
- .to("mock:tap");
-]]></script>
-</div></div><h4 id="WireTap-XMLDSL">XML DSL</h4><p>The XML DSL is slightly
different than Java DSL in how you configure the message body and headers
using <strong><code><body></code></strong> and
<strong><code><setHeader></code></strong>:</p><div class="code panel pdl"
style="border-width: 1px;"><div class="codeContent panelContent pdl">
-<script class="brush: xml; gutter: false; theme: Default"
type="syntaxhighlighter"><![CDATA[
-<route>
- <from uri="direct:start"/>
- <!-- tap a new message and send it to direct:tap -->
- <!-- the new message should be Bye World with 2 headers -->
- <wireTap uri="direct:tap">
- <!-- create the new tap message body and headers -->
- <body><constant>Bye World</constant></body>
- <setHeader
headerName="id"><constant>123</constant></setHeader>
- <setHeader
headerName="date"><simple>${date:now:yyyyMMdd}</simple></setHeader>
- </wireTap>
- <!-- here we continue routing the original message -->
- <to uri="mock:result"/>
-</route>
-]]></script>
-</div></div><h3
id="WireTap-UsingonPreparetoExecuteCustomLogicwhenPreparingMessages">Using <code>onPrepare</code>
to Execute Custom Logic when Preparing Messages</h3><p><strong>Available as of
Camel 2.8</strong></p><p>See details at <a shape="rect"
href="multicast.html">Multicast</a></p><p></p><h4
id="WireTap-UsingThisPattern">Using This Pattern</h4>
-
-<p>If you would like to use this EIP Pattern then please read the <a
shape="rect" href="getting-started.html">Getting Started</a>, you may also find
the <a shape="rect" href="architecture.html">Architecture</a> useful
particularly the description of <a shape="rect"
href="endpoint.html">Endpoint</a> and <a shape="rect"
href="uris.html">URIs</a>. Then you could try out some of the <a shape="rect"
href="examples.html">Examples</a> first before trying this pattern
out.</p></div>
+<div class="wiki-content maincontent"><h3 id="WireTap-WireTap">Wire
Tap</h3><p><a shape="rect" class="external-link"
href="http://www.enterpriseintegrationpatterns.com/WireTap.html";
rel="nofollow">Wire Tap</a> (from the <a shape="rect"
href="enterprise-integration-patterns.html">EIP patterns</a>) allows you to
route messages to a separate location while they are being forwarded to the
ultimate destination.</p><p><span class="confluence-embedded-file-wrapper"><img
class="confluence-embedded-image confluence-external-resource"
src="http://www.enterpriseintegrationpatterns.com/img/WireTap.gif";
data-image-src="http://www.enterpriseintegrationpatterns.com/img/WireTap.gif";></span></p><parameter
ac:name="title">Streams</parameter><rich-text-body><p>If you <a shape="rect"
href="wire-tap.html">Wire Tap</a> a stream message body then you should
consider enabling <a shape="rect" href="stream-caching.html">Stream caching</a>
to ensure the message body can be read at each endpoint. See more deta
ils at <a shape="rect" href="stream-caching.html">Stream
caching</a>.</p></rich-text-body><h3 id="WireTap-Options">Options</h3><div
class="table-wrap"><table class="confluenceTable"><tbody><tr><th colspan="1"
rowspan="1" class="confluenceTh">Name</th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Default</p></th><th colspan="1" rowspan="1"
class="confluenceTh"><p>Description</p></th></tr><tr><td colspan="1"
rowspan="1" class="confluenceTd"><p><code>uri</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong><span style="color:
rgb(255,0,0);">Mandatory</span>:</strong> The URI of the endpoint to which the
wire-tapped message should be sent.</p><p>From <strong>Camel 2.16</strong>:
support for dynamic <strong><code>to</code></strong> URIs is as documented
in <a shape="rect" class="external-link"
href="http://camel.apache.org/message-endpoint.html"; style="line-height:
1.4285715;">Message Endp
oint.</a></p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>executorServiceRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Reference ID of a custom <a shape="rect"
href="threading-model.html">Thread Pool</a> to use when processing the
wire-tapped messages.</p><p>When not set, Camel will use an instance of the
default thread pool.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>processorRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p>Reference ID of a custom <a shape="rect"
href="processor.html">Processor</a> to use for creating a new
message.</p><p>See "<strong>Sending a New Exchange</strong>"
below.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>copy</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>true
</code></p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>Camel 2.3</strong>: Whether to copy the <a
shape="rect" href="exchange.html">Exchange</a> before wire-tapping the
message.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>onPrepareRef</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"><p> </p></td><td colspan="1" rowspan="1"
class="confluenceTd"><p><strong>Camel 2.8:</strong> Reference identifier of a
custom <a shape="rect" href="processor.html">Processor</a> to prepare the copy
of the <a shape="rect" href="exchange.html">Exchange</a> to be wire-tapped.
This allows you to do any custom logic, such as deep-cloning the message
payload.</p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>cacheSize</code></p></td><td colspan="1"
rowspan="1" class="confluenceTd"> </td><td colspan="1" rowspan="1"
class="confluenceTd"><p><span style="color: rgb(0,0,0);"><strong>Camel
2.16:</strong> Allows to c
onfigure the cache size for
the </span><strong><code>ProducerCache</code></strong><span style="color:
rgb(0,0,0);"> which caches producers for reuse. Will by default use the
default cache size which is <strong><code>1000</code></strong>.
</span></p><p><span style="color: rgb(0,0,0);">Setting the value
to <strong><code>-1</code></strong> allows to turn off the cache all
together.</span></p></td></tr><tr><td colspan="1" rowspan="1"
class="confluenceTd"><p><code>ignoreInvalidEndpoint</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><code>false</code></p></td><td
colspan="1" rowspan="1" class="confluenceTd"><p><strong>Camel 2.16:</strong>
<span style="color: rgb(0,0,0);">Whether to ignore an endpoint URI that could
not be resolved. </span></p><p><span style="color: rgb(0,0,0);">When
<strong><code>false</code></strong>, Camel will throw an exception when it
identifies an invalid endpoint
URI.</span></p></td></tr></tbody></table></div><h3 id="WireTap-WireT
apThreadpool">WireTap Threadpool</h3><p>The <a shape="rect"
href="wire-tap.html">Wire Tap</a> uses a thread pool to process the tapped
messages. This thread pool will by default use the settings detailed at <a
shape="rect" href="threading-model.html">Threading Model</a>. In particular,
when the pool is exhausted (with all threads utilized), further wiretaps will
be executed synchronously by the calling thread. To remedy this, you can
configure an explicit thread pool on the <a shape="rect"
href="wire-tap.html">Wire Tap</a> having either a different rejection policy, a
larger worker queue, or more worker threads.</p><h3
id="WireTap-WireTapNode">WireTap Node</h3><p>Camel's Wire Tap node supports two
flavors when tapping an <a shape="rect"
href="exchange.html">Exchange</a>:</p><ul><li>With the traditional Wire Tap,
Camel will copy the original <a shape="rect" href="exchange.html">Exchange</a>
and set its <a shape="rect" href="exchange-pattern.html">Exchange Pattern</a>
to <strong><code
>InOnly</code></strong>, as we want the tapped <a shape="rect"
>href="exchange.html">Exchange</a> to be sent in a fire and forget style. The
>tapped <a shape="rect" href="exchange.html">Exchange</a> is then sent in a
>separate thread so it can run in parallel with the original. Beware that only
>the Exchange is copied - Wire Tap won't do a deep clone (unless you specify a
>custom processor via <strong><code>onPrepareRef</code></strong> which
>does that). So all copies could share objects from the original
>Exchange.</li><li>Camel also provides an option of sending a new <a
>shape="rect" href="exchange.html">Exchange</a> allowing you to populate it
>with new values.</li></ul><h4
>id="WireTap-SendingaCopy(traditionalwiretap)">Sending a Copy (traditional
>wiretap)</h4><p><strong>Using the <a shape="rect"
>href="fluent-builders.html">Fluent
>Builders</a></strong><plain-text-body>{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/WireTapTest.java}</plain
-text-body><strong>Using the <a shape="rect"
href="spring-xml-extensions.html">Spring XML
Extensions</a></strong><plain-text-body>{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringWireTapTest.xml}</plain-text-body></p><h4
id="WireTap-SendingaNew">Sending a New <a shape="rect"
href="exchange.html">Exchange</a></h4><p><strong>Using the <a shape="rect"
href="fluent-builders.html">Fluent Builders</a></strong><br clear="none"> Camel
supports either a processor or an <a shape="rect"
href="expression.html">Expression</a> to populate the new <a shape="rect"
href="exchange.html">Exchange</a>. Using a processor gives you full power over
how the <a shape="rect" href="exchange.html">Exchange</a> is populated as you
can set properties, headers, etc. An <a shape="rect"
href="expression.html">Expression</a> can only be used to set
the <strong><code>IN</code></strong> body.</p><p>From <strong>Camel
2.3</strong>: the <a sh
ape="rect" href="expression.html">Expression</a> or <a shape="rect"
href="processor.html">Processor</a> is pre-populated with a copy of the
original <a shape="rect" href="exchange.html">Exchange</a>, which allows you to
access the original message when you prepare a new <a shape="rect"
href="exchange.html">Exchange</a> to be sent. You can use the
<strong><code>copy</code></strong> option (enabled by default) to indicate
whether you want this. If you set <strong><code>copy=false</code></strong>,
then it works as in <strong>Camel 2.2</strong> or older where the <a
shape="rect" href="exchange.html">Exchange</a> will be empty.</p><p>Below is
the processor variation. This example is from <strong>Camel 2.3</strong>, where
we disable <strong><code>copy</code></strong> by passing in
<strong><code>false</code></strong> to create a new, empty <a shape="rect"
href="exchange.html">Exchange</a>.<plain-text-body>{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/pr
ocessor/WireTapUsingFireAndForgetTest.java}</plain-text-body>Here is the <a
shape="rect" href="expression.html">Expression</a> variation. In the following
example we disable copying by setting
<strong><code>copy</code><code>=false</code></strong> which results in the
creation of a new, empty <a shape="rect"
href="exchange.html">Exchange</a>.<plain-text-body>{snippet:id=e2|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/WireTapUsingFireAndForgetTest.java}</plain-text-body><strong>Using
the <a shape="rect" href="spring-xml-extensions.html">Spring XML
Extensions</a></strong><br clear="none"> The processor variation, which uses
a <strong><code>processorRef</code></strong> attribute to refer to a
Spring bean by
ID:<plain-text-body>{snippet:id=e2|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringWireTapUsingFireAndForgetTest.xml}</plain-text-body>Here
is the <a shape="rect" href="expression.html">
Expression</a> variation, where the expression is defined in
the <strong><code>body</code></strong>
tag:<plain-text-body>{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringWireTapUsingFireAndForgetTest.xml}</plain-text-body>This
variation accesses the body of the original message and creates a new <a
shape="rect" href="exchange.html">Exchange</a> based on the <a shape="rect"
href="expression.html">Expression</a>. It will create a new Exchange and have
the body contain <code>"<strong>Bye ORIGINAL BODY MESSAGE
HERE</strong>"</code><plain-text-body>{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringWireTapUsingFireAndForgetCopyTest.xml}</plain-text-body></p><h4
id="WireTap-FurtherExample">Further Example</h4><p>For another example of this
pattern, refer to the <a shape="rect" class="external-link"
href="http://svn.apache.org/repos/asf/came
l/trunk/camel-core/src/test/java/org/apache/camel/processor/WireTapTest.java">wire
tap test case</a>.</p><h3 id="WireTap-UsingDynamicURIs">Using Dynamic
URIs</h3><p><strong>Available as of Camel 2.16:</strong></p><p>For example to
wire tap to a dynamic URI, then it supports the same dynamic URIs as documented
in <a shape="rect" href="message-endpoint.html">Message Endpoint</a>. For
example to wire tap to a JMS queue where the header ID is part of the queue
name:</p><plain-text-body>from("direct:start")
+ .wireTap("jms:queue:backup-${header.id}")
+ .to("bean:doSomething");</plain-text-body><p> </p><h3
id="WireTap-SendingaNewandSetHeadersinDSL">Sending a New <a shape="rect"
href="exchange.html">Exchange</a> and Set Headers in
DSL</h3><p><strong>Available as of Camel 2.8</strong></p><p>If you send a new
message using <a shape="rect" href="wire-tap.html">Wire Tap</a>, then you could
only set the message body using an <a shape="rect"
href="expression.html">Expression</a> from the DSL. If you also need to set
headers, you would have to use a <a shape="rect"
href="processor.html">Processor</a>. From <strong>Camel 2.8</strong>: it's
possible to set headers as well using the DSL.</p><p>The following example
sends a new message which has</p><ul class="alternate"><li><strong><code>Bye
World</code></strong> as message body.</li><li>A header with
key <strong><code>id</code></strong> with the value
<strong><code>123</code></strong>.</li><li>A header with
key <strong><code>date</code></strong> which has current date as val
ue.</li></ul><h4 id="WireTap-JavaDSL">Java
DSL</h4><p><plain-text-body>{snippet:id=e1|lang=java|url=camel/trunk/camel-core/src/test/java/org/apache/camel/processor/WireTapNewExchangeTest.java}</plain-text-body></p><h4
id="WireTap-XMLDSL">XML DSL</h4><p>The XML DSL is slightly different than Java
DSL in how you configure the message body and headers
using <strong><code><body></code></strong> and
<strong><code><setHeader></code></strong>:<plain-text-body>{snippet:id=e1|lang=xml|url=camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/processor/SpringWireTapNewExchangeTest.xml}</plain-text-body></p><h3
id="WireTap-UsingonPreparetoExecuteCustomLogicwhenPreparingMessages">Using <code>onPrepare</code>
to Execute Custom Logic when Preparing Messages</h3><p><strong>Available as of
Camel 2.8</strong></p><p>See details at <a shape="rect"
href="multicast.html">Multicast</a></p><p><parameter ac:name=""><a shape="rect"
href="using-this-pattern.html
">Using This Pattern</a></parameter></p></div>
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