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      <h1>PropertyConsts Description</h1>
      <p>
        <font size="-2">by&nbsp;Peter B. West</font>
      </p>
      <ul class="minitoc">
        <li>
          <a href="#N10014">Introduction</a>
        </li>
      </ul>
      
      <a name="N10014"></a>
      <h3>Introduction</h3>
      <p>
        
        <a href="javascript:parent.displayCode(
           'PropertyConsts.html#PropertyConstsClass'
        )">This class</a>, and the singleton object which is <a
        href="javascript:parent.displayCode(
        'PropertyConsts.html#pconsts' )">generated by the static
        initializer</a>, is essentially a repository of
        &lt;property&gt; class instances and the static data from
        those classes of <span
        class="codefrag">org.apache.fop.fo.property</span>.
        The heart of this class is the method <a href=
        "javascript:parent.displayCode(
        'PropertyConsts.html#setupProperty' )"><span class="codefrag"
        >setupProperty</span ></a>.  Whenever access to the data or
        methods of a property class is required, this method in the
        singleton must be called to ensure that an instance of the
        property exists and that the static data from that instance
        has been extracted.
      </p>

      <div class="frame note">
        <div class="label">Note</div>
        <div class="content">
          An alternative to this requirement would be to pre-load all
          of the individual property classes during the system
          initialization phase.  This is not done currently because of
          the start-up expense of the required class loading for over
          three hundred classes, and the relatively low added expense
          of checking for the existence of a property instance before
          every access.  Given that FOP is increasingly used in a
          server environment, it may prove acceptable in the long run
          to change to pre-loading.
        </div>
      </div>

      <p>
        The class name is generated and stored in the <a
        href="javascript:parent.displayCode(
        'PropertyConsts.html#classNames' )"><span class="codefrag"
        >classNames</span ></a> array; a class instance is generated
        from the name and stored in the <a
        href="javascript:parent.displayCode(
        'PropertyConsts.html#classes' )"><span class="codefrag"
        >classes</span ></a> array; and an instance of the class is
        generated from the class object and stored in the <a
        href="javascript:parent.displayCode(
        'PropertyConsts.html#properties' )"><span class="codefrag"
        >properties</span ></a> array.
      </p>

      <p>
        The other data gathering facilities and access methods of this
        class will be examined in conjunction with the various types
        of property classes.
      </p>

      <p>
        <strong>Previous:</strong> <a href = "classes-overview.html"
        >Property classes overview</a>
      </p>
      <p>
        <strong>Next:</strong> <a href= "simple-properties.html"
                                  >Simple property classes</a>
      </p>
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