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<h1>Object Types In TA</h1>
<p>When working in <span class="MCTextPopup"><a href="javascript:void(0);" class="MCTextPopupSpot" onclick="FMCTextPopup( event, this ); return false;">TA<img style="border: none;margin-left: 5px;" src="../../../SkinSupport/ExpandingClosed.gif" MadCap:altsrc="../../../SkinSupport/ExpandingOpen.gif" class="MCExpandingIcon" onload="if ( typeof( FMCPreloadImage ) == 'function' ) { FMCPreloadImage( '../../../SkinSupport/ExpandingOpen.gif' ); }" /></a><span class="MCTextPopupBody" style="display: none; ">Transparent Activation</span></span> enabled environment you must remember that db4o treats Activatable (TA Aware) and non Activatable (other) types differently. </p>
<p>In general we can distinguish the following types:</p>
<ul>
<li value="1">Value types with no identity (char, boolean, integer etc). These types are handled internally by db4o engine and behave the same in TA enabled and disabled modes.</li>
<li value="2">Activatable types, as it is clear from the name, implement Activatable interface and are responsible for their own activation.</li>
<li value="3">Non Activatable type - all the other types, including user types or third-party classes.</li>
</ul>
<p>As it was mentioned <a href="ta_implementation.htm">before</a> in TA enabled mode non-Activatable types are fully activated whereas Activatable types have 0 activation depth and are getting activated as requested. </p>
<p>Let's look at an example model below, which includes Activatable and non-Activatable classes:</p>
<p>
<img src="object_types_in_ta/ta.gif" />
</p>
<p>Querying and traversing in TA enabled mode:</p>
<p MadCap:conditions="Global.Primary:java" />
<p MadCap:conditions="Primary..NET,Primary.c#,Primary.All languages">
<p>c#: </p>
<p><code>Customer c =
container.QueryByExample(typeof(Customer)).Next();</code>
</p>
</p>
<p MadCap:conditions="Global.Primary:cs" />
<p MadCap:conditions="Primary..NET,Primary.VB.NET,Primary.All languages">
<p>VB: </p>
<p><code>Dim c as Customer =
container.QueryByExample(GetType(Customer)).Next();</code>
</p>
</p>
<p MadCap:conditions="Global.Primary:vb" />
<p>At this point the following paths should be already activated (Customer is not Activatable):</p>
<p><code>c.name</code><code>c.addresses</code><code>.addresses[N].firstLine</code>
</p>
<p> </p>
<p><code>c.addresses[N].country</code> - available but not activated (Activatable type).</p>
<p> </p>
<p>Country.getState would cause the Country object to be activated</p>
<p MadCap:conditions="Global.Primary:java" />
<p MadCap:conditions="Primary..NET,Primary.c#,Primary.All languages">
<p>c#: </p>
<p><code>State state = c.Address[0].Country.GetState(someZipCode);</code>
</p>
</p>
<p MadCap:conditions="Global.Primary:cs" />
<p MadCap:conditions="Primary..NET,Primary.VB.NET,Primary.All languages">
<p>VB:</p>
<p><code>Dim state As State = <br />c.Address(0).Country.GetState(someZipCode);</code>
</p>
</p>
<p MadCap:conditions="Global.Primary:vb" />
<p>At this point the following paths become activated
</p>
<p><code>c.addresses[0].country.states</code><code>.addresses[0]<br />.country.states[N].name</code>
</p>
<p><code>c.addresses[0].country.states[N].city</code><code>.addresses[0]<br />.country.states[N].cities[N]</code>
</p>
<p>- available but not
activated (Activatable type)</p>
<p> </p>The following general rules apply:
<ol><li value="1">Arrays of Arrays of non Activatable types: non Activatable behavior</li><li value="2">Arrays of Arrays of Activatable types: non Activatable behavior except for leaves</li><li value="3">JDK collections: non Activatable behavior</li><li value="4">Value types with references to non Activatable reference types and to Activatable
reference types: the non Activatable path should be activated fully; Activatable
path stops activation.</li></ol><script type="text/javascript" src="../../../SkinSupport/MadCapBodyEnd.js"></script></body>
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