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   <title>Chapter&nbsp;6.&nbsp;OSGi 4.2 Blueprint Container</title><link rel="stylesheet" href="css/html.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.72.0"><link rel="start" href="index.html" title="Eclipse Gemini Blueprint Reference Guide"><link rel="up" href="reference.html" title="Part&nbsp;II.&nbsp;Reference Documentation"><link rel="prev" href="reference.html" title="Part&nbsp;II.&nbsp;Reference Documentation"><link rel="next" href="bnd-app-ctx.html" title="Chapter&nbsp;7.&nbsp;Bundles and Application Contexts"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="blueprint"></a>Chapter&nbsp;6.&nbsp;OSGi 4.2 Blueprint Container</h2></div></div></div><p>Based on the Gemini Blueprint programming model, the OSGi Alliance introduced in OSGi 4.2 Release
	the Blueprint Container specification (part of the Compendium Service). Gemini Blueprint 1.0 serves as 
	the Blueprint Reference <a xmlns:xlink="http://www.w3.org/1999/xlink" href="http://en.wikipedia.org/wiki/Reference_implementation" target="_top">Implementation</a>
	- the official, complete implementation of the spec.
	</p><p>Existing and new users have the freedom to mix and match the programming model they want, since Eclipse Gemini Blueprint supports 
	both the Spring DM 1.x declarations and the Blueprint one, inside the same application, provided the default namespace is Blueprint
  and the Blueprint files are stored in the folder <code class="literal">META-INF/spring</code>.
	</p><p>Please note that this documentation will focus on Gemini Blueprint specific configurations and options; for Blueprint specific
	behaviour please refer to the OSGi 4.2 Compendium spec, section 121.</p><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="blueprint:requirements"></a>6.1.&nbsp;Blueprint Requirements</h2></div></div></div><p>The Blueprint Container spec is part of the OSGi 4.2 release and relies on it, in its API. Thus, 
		in order to use Blueprint, one must use an OSGi 4.2 compatible platform as a runtime environment. Gemini Blueprint itself 
		requires only an OSGi 4.0 framework so if 4.2 is not an option, one can safely downgrade at the loss of the Blueprint
		model which can be built on top of Spring/Gemini Blueprint.
		</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/admons/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top">On environments prior to OSGi 4.2, Gemini Blueprint will disable the Blueprint functionality automatically - users will be notified 
		through a log message similar to the following:

	    <pre class="screen">Pre-4.2 OSGi platform detected; disabling Blueprint Container functionality</pre></td></tr></table></div></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="blueprint:differences"></a>6.2.&nbsp;Blueprint/Gemini Blueprint Differences</h2></div></div></div><p>There are a lot of similarities in terms of functionality and configuration between Gemini Blueprint 1.x and Blueprint which should be 
		no surprise considering that Spring DM was the basis of the Blueprint spec. In addition to fully supporting the Blueprint configuration schema, 
		DM 2.x enhanced its declarations by providing option that allow for Blueprint specific behaviour. The table below aggregates the most 
		important user facing differences between Spring/Gemini Blueprint configurations and Blueprint. Additional comparison information is available
		throughout the documentation (such as <a href="app-deploy.html#app-deploy:headers:blueprint" title="8.2.&nbsp;Blueprint Manifest Configuration Comparison">Section&nbsp;8.2, &#8220;Blueprint Manifest Configuration Comparison&#8221;</a> or <a href="service-registry.html#service-registry:export:blueprint" title="9.1.10.2.&nbsp;Blueprint service Comparison">Section&nbsp;9.1.10.2, &#8220;Blueprint <code class="literal">service</code> Comparison&#8221;</a>).
		Again, one can simply switch between the two definition styles, if need be.</p><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="blueprint:differences:xml"></a>6.2.1.&nbsp;XML Declarations</h3></div></div></div><p>Most of the XML declarations are similar between Spring and Blueprint. Using the Spring 
		<a xmlns:xlink="http://www.w3.org/1999/xlink" href="http://static.springsource.org/spring/docs/2.5.x/reference/new-in-2.html#new-in-2-ioc-configuration" target="_top">namespace</a> mechanism, 
		the same configuration can contain both Spring, Gemini Blueprint, Blueprint and other namespaces. Moreover, custom elements can be used for virtually
		all elements of a Spring configuration (namespace, bean declaration, decoration, etc...). The table below focuses <span class="emphasis"><em>only</em></span>
		on the usual, standard Spring namespaces and their Blueprint equivalent.</p><div class="table"><a name="spring-vs-blueprint-xml"></a><p class="title"><b>Table&nbsp;6.1.&nbsp;XML Configuration Differences</b></p><div class="table-contents"><table summary="XML Configuration Differences" width="100%" border="1"><colgroup><col><col><col></colgroup><thead><tr><th>Element/Attribute</th><th>Gemini Blueprint</th><th>Blueprint</th></tr></thead><tbody><tr><td>Namespace Declaration</td><td><p><code class="literal">http://www.springframework.org/schema/beans</code></p> 
                <p>or <code class="literal">http://www.springframework.org/schema/osgi</code></p></td><td><code class="literal">http://www.osgi.org/xmlns/blueprint/v1.0.0</code></td></tr><tr><td>Root Element</td><td><code class="literal">&lt;beans&gt;</code></td><td><code class="literal">&lt;blueprint&gt;</code></td></tr><tr><td>Default Lazy</td><td><code class="literal">default-lazy</code></td><td><code class="literal">default-activation</code></td></tr><tr><td>Default Init Method</td><td><code class="literal">default-init-method</code></td><td><code class="literal">-</code></td></tr><tr><td>Default Destroy Method</td><td><code class="literal">default-destroy-method</code></td><td><code class="literal">-</code></td></tr><tr><td>Default Autowire Strategy</td><td><code class="literal">default-autowire</code>, <code class="literal">default-autowire-candidates</code></td><td><code class="literal">-</code></td></tr><tr><td>Root Element</td><td><code class="literal">&lt;beans&gt;</code></td><td><code class="literal">&lt;blueprint&gt;</code></td></tr><tr><td>Bean ID</td><td><code class="literal">id</code></td><td><code class="literal">id</code></td></tr><tr><td>Bean Name/Alias</td><td><code class="literal">name</code>/<code class="literal">&lt;alias&gt;</code></td><td><code class="literal">-</code></td></tr><tr><td>Bean Class</td><td><code class="literal">class</code></td><td><code class="literal">class</code></td></tr><tr><td>Bean Scope Name</td><td><code class="literal">scope</code></td><td><code class="literal">scope</code></td></tr><tr><td>Built-in Scopes</td><td><code class="literal">singleton</code>, <code class="literal">prototype</code>, <code class="literal">request</code>, <code class="literal">session</code>, <code class="literal">bundle</code></td><td><code class="literal">singleton</code>, <code class="literal">prototype</code></td></tr><tr><td>Lazy Initialization Name/Values</td><td><code class="literal">lazy-init</code>=<code class="literal">true/false</code></td><td><code class="literal">activation</code>=<code class="literal">lazy/eager</code></td></tr><tr><td>Depends</td><td><code class="literal">depends-on</code></td><td><code class="literal">depends-on</code></td></tr><tr><td>Init Method</td><td><code class="literal">init-method</code></td><td><code class="literal">init-method</code></td></tr><tr><td>Destroy Method</td><td><code class="literal">destroy-method</code></td><td><code class="literal">destroy-method</code></td></tr><tr><td>Factory Method</td><td><code class="literal">factory-method</code></td><td><code class="literal">factory-method</code></td></tr><tr><td>Factory Bean</td><td><code class="literal">factory-bean</code></td><td><code class="literal">factory-ref</code></td></tr><tr><td>Bean Inheritance</td><td><code class="literal">parent</code></td><td><code class="literal">-</code></td></tr><tr><td>Autowire Strategy</td><td><code class="literal">autowire</code>, <code class="literal">autowire-candidate</code></td><td><code class="literal">-</code></td></tr><tr><td>Constructor</td><td><code class="literal">&lt;constructor-arg&gt;</code></td><td><code class="literal">&lt;argument&gt;</code></td></tr><tr><td>Property</td><td><code class="literal">&lt;property&gt;</code></td><td><code class="literal">&lt;property&gt;</code></td></tr><tr><td>Value</td><td><code class="literal">&lt;value&gt;</code></td><td><code class="literal">&lt;value&gt;</code></td></tr><tr><td>Service Exporter</td><td><code class="literal">&lt;service&gt;</code></td><td><code class="literal">&lt;service&gt;</code></td></tr><tr><td>Service Importer</td><td><code class="literal">&lt;reference&gt;/&lt;list&gt;/&lt;set&gt;</code></td><td><code class="literal">&lt;reference&gt;/&lt;list&gt;</code></td></tr></tbody></table></div></div><br class="table-break"><p>The configurations below are equivalent in terms of functionality:</p><pre class="programlisting">&lt;<span class="hl-tag">?xml version="1.0" encoding="UTF-8"?</span>&gt;
&lt;<span class="hl-tag">blueprint</span> <span class="hl-attribute">xmlns</span>=<span class="hl-value">"http://www.osgi.org/xmlns/blueprint/v1.0.0"</span> <span class="hl-attribute">default-activation</span>=<span class="hl-value">"lazy"</span>&gt;
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"object"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.Object"</span>/&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"length"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.Integer"</span>&gt;
        &lt;<span class="hl-tag">argument</span> <span class="hl-attribute">value</span>=<span class="hl-value">"4"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"buffer"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.StringBuffer"</span> <span class="hl-attribute">depends-on</span>=<span class="hl-value">"simple"</span>&gt;
    	&lt;<span class="hl-tag">property</span> <span class="hl-attribute">name</span>=<span class="hl-value">"length"</span> <span class="hl-attribute">ref</span>=<span class="hl-value">"length"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"current-time"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.System"</span> <span class="hl-attribute">factory-method</span>=<span class="hl-value">"currentTimeMillis"</span> <span class="hl-attribute">scope</span>=<span class="hl-value">"prototype"</span>/&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"list"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.util.ArrayList"</span> <span class="hl-attribute">destroy-method</span>=<span class="hl-value">"clear"</span> <span class="hl-attribute">activation</span>=<span class="hl-value">"eager"</span>&gt;
    	&lt;<span class="hl-tag">argument</span> <span class="hl-attribute">ref</span>=<span class="hl-value">"length"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
&lt;<span class="hl-tag">/blueprint</span>&gt;</pre><pre class="programlisting">&lt;<span class="hl-tag">?xml version="1.0" encoding="UTF-8"?</span>&gt;
&lt;<span class="hl-tag">beans</span> <span class="hl-attribute">xmlns</span>=<span class="hl-value">"http://www.springframework.org/schema/beans"</span>
    <span class="hl-attribute">xmlns:xsi</span>=<span class="hl-value">"http://www.w3.org/2001/XMLSchema-instance"</span>
    <span class="hl-attribute">xsi:schemaLocation</span>=<span class="hl-value">"http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"</span>
    <span class="hl-attribute">default-lazy-init</span>=<span class="hl-value">"true"</span>&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"object"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.Object"</span>/&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"length"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.Integer"</span>&gt;
        &lt;<span class="hl-tag">constructor-arg</span> <span class="hl-attribute">value</span>=<span class="hl-value">"4"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"buffer"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.StringBuffer"</span> <span class="hl-attribute">depends-on</span>=<span class="hl-value">"simple"</span>&gt;
    	&lt;<span class="hl-tag">property</span> <span class="hl-attribute">name</span>=<span class="hl-value">"length"</span> <span class="hl-attribute">ref</span>=<span class="hl-value">"length"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"current-time"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.System"</span> <span class="hl-attribute">factory-method</span>=<span class="hl-value">"currentTimeMillis"</span> <span class="hl-attribute">scope</span>=<span class="hl-value">"prototype"</span>/&gt;
    
    &lt;<span class="hl-tag">bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"list"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.util.ArrayList"</span> <span class="hl-attribute">destroy-method</span>=<span class="hl-value">"clear"</span> <span class="hl-attribute">lazy-init</span>=<span class="hl-value">"false"</span>&gt;
    	&lt;<span class="hl-tag">constructor-arg</span> <span class="hl-attribute">ref</span>=<span class="hl-value">"length"</span>/&gt;
    &lt;<span class="hl-tag">/bean</span>&gt;
&lt;<span class="hl-tag">/beans</span>&gt;</pre><p>As mentioned before, in Gemini Blueprint one can mix and match the namespaces provided the default namespace is Blueprint
  and the Blueprint files are stored in the folder <code class="literal">META-INF/spring</code>:</p><pre class="programlisting">&lt;<span class="hl-tag">blueprint</span> <span class="hl-attribute">xmlns</span>=<span class="hl-value">"http://www.osgi.org/xmlns/blueprint/v1.0.0"</span>
  <span class="hl-attribute">xmlns:beans</span>=<span class="hl-value">"http://www.springframework.org/schema/beans"</span>
  <span class="hl-attribute">xmlns:xsi</span>=<span class="hl-value">"http://www.w3.org/2001/XMLSchema-instance"</span>
  <span class="hl-attribute">xsi:schemaLocation</span>=<span class="hl-value">"
    http://www.osgi.org/xmlns/blueprint/v1.0.0 http://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"</span>&gt;
       
    &lt;<span class="hl-tag">beans:bean</span> <span class="hl-attribute">id</span>=<span class="hl-value">"anInteger"</span> <span class="hl-attribute">class</span>=<span class="hl-value">"java.lang.Integer"</span>&gt;
      &lt;<span class="hl-tag">beans:constructor-arg</span> <span class="hl-attribute">value</span>=<span class="hl-value">"10"</span>/&gt;
    &lt;<span class="hl-tag">/beans:bean</span>&gt;
    
    &lt;<span class="hl-tag">service</span> <span class="hl-attribute">ref</span>=<span class="hl-value">"anInteger"</span> <span class="hl-attribute">interface</span>=<span class="hl-value">"java.lang.Comparable"</span> /&gt;
&lt;<span class="hl-tag">/blueprint</span>&gt;</pre><p>The example above uses the Gemini Blueprint and Spring <code class="literal">beans</code> namespaces.</p></div><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="blueprint:differences:container"></a>6.2.2.&nbsp;Container Capabilities</h3></div></div></div><p>From a container perspective, the Blueprint spec standardizes the a subset of the Spring container. A high-level view comparison, by no 
		means comprehensive, is summarized in the table below:</p><div class="table"><a name="spring-vs-blueprint-container"></a><p class="title"><b>Table&nbsp;6.2.&nbsp;Container Capabilities Differences</b></p><div class="table-contents"><table summary="Container Capabilities Differences" width="100%" border="1"><colgroup><col><col><col></colgroup><thead><tr><th>Feature</th><th>Gemini Blueprint</th><th>Blueprint</th></tr></thead><tbody><tr><td colspan="3" align="center"><span class="emphasis"><em>Object Instantiation</em></span></td></tr><tr><td>Constructor Instantiation</td><td>Y</td><td>Y</td></tr><tr><td>Static Factory Instantiation</td><td>Y</td><td>Y</td></tr><tr><td>Instance Factory Instantiation</td><td>Y</td><td>Y</td></tr><tr><td colspan="3" align="center"><span class="emphasis"><em>Dependency Injection</em></span></td></tr><tr><td>Constructor Injection</td><td>Y</td><td>Y</td></tr><tr><td>Setter Injection</td><td>Y</td><td>Y</td></tr><tr><td>Field Injection</td><td>Y</td><td>N</td></tr><tr><td>Method Injection</td><td>Y</td><td>N</td></tr><tr><td>Arbitrary Method Injection</td><td>Y</td><td>N</td></tr><tr><td>Autowiring</td><td>Y</td><td>N</td></tr><tr><td colspan="3" align="center"><span class="emphasis"><em>Component Lifecycle</em></span></td></tr><tr><td>Lazy Initialization</td><td>Y</td><td>Y</td></tr><tr><td>Bean Scopes</td><td>Y</td><td>Y</td></tr><tr><td>Custom Bean Scopes</td><td>Y</td><td>N</td></tr><tr><td>Built-in Callbacks</td><td>Y</td><td>N</td></tr><tr><td>Custom Callbacks</td><td>Y</td><td>Y</td></tr><tr><td>Initialization Processing</td><td>Y</td><td>N</td></tr></tbody></table></div></div><br class="table-break"><p>As with the XML configuration, since Gemini Blueprint translates the Blueprint configuration into Spring metadata, one can rely on Spring for features
		beyond the Blueprint container. For example, one can configure a bean using Blueprint and use annotation on the same instance, for field injection. 
		The same object can implement Spring's <code class="literal">Aware</code> interfaces or rely on other post processors for certain behaviour.</p></div><p>Note that additional information on Blueprint is available through out the documentation.	These being said, it is highly recommended to read 
		and use the Blueprint specification as guidance, if the Blueprint Container becomes	the programming model of choice.</p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="blueprint:using"></a>6.3.&nbsp;Using Blueprint</h2></div></div></div><p>There are no extra jars or steps that need to be executed to <span class="emphasis"><em>enable</em></span> the Blueprint functionality in Gemini Blueprint. 
		This is built directly into the core, in fact the Blueprint APIs are exported by the Gemini Blueprint core. Please see the next section for 
		information on how to install Gemini Blueprint and the OSGi compendium spec (section 121) for Blueprint related information such as bootstrapping
		and configuration locations. For those in a hurry, simply install and start the Gemini Blueprint jars (io, core, extender) and their dependencies
		(namely Spring and slf4j) and you should be all set: Gemini Blueprint will automatically detect the running environment and the types of bundles started.
		</p></div></div><div xmlns:fo="http://www.w3.org/1999/XSL/Format" class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="reference.html">Prev</a>&nbsp;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right">&nbsp;<a accesskey="n" href="bnd-app-ctx.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Part&nbsp;II.&nbsp;Reference Documentation&nbsp;</td><td width="20%" align="center"><span style="color:white;font-size:90%;"><a href="http://www.SpringSource.com/" title="SpringSource - Spring from the Source">Sponsored by SpringSource
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