cvs commit: jakarta-velocity/src/java/org/apache/velocity/injector Injector.java ForeachInjector.java IfInjector.java MethodInjector.java PropertyInjector.java VariableInjector.java

[jv...@locus.apache.org]

jvanzyl     00/08/27 15:59:08

  Modified:    src/java/org/apache/velocity/injector Injector.java
  Removed:     src/java/org/apache/velocity/injector ForeachInjector.java
                        IfInjector.java MethodInjector.java
                        PropertyInjector.java VariableInjector.java
  Log:
  - added class documentation for the injector.
  
  Revision  Changes    Path
  1.3       +107 -2    jakarta-velocity/src/java/org/apache/velocity/injector/Injector.java
  
  Index: Injector.java
  ===================================================================
  RCS file: /home/cvs/jakarta-velocity/src/java/org/apache/velocity/injector/Injector.java,v
  retrieving revision 1.2
  retrieving revision 1.3
  diff -u -r1.2 -r1.3
  --- Injector.java	2000/08/26 18:47:01	1.2
  +++ Injector.java	2000/08/27 22:59:06	1.3
  @@ -54,7 +54,112 @@
    * <http://www.apache.org/>.
    */
   
  -public interface Injector
  +import org.apache.velocity.Context;
  +import org.apache.velocity.Template;
  +import org.apache.velocity.parser.SimpleNode;
  +import org.apache.velocity.visitor.InjectorVisitor;
  +
  +/**
  + * This class is responsible for storing the location
  + * of an injection point in a preparsed template, for
  + * storing the root of the <b>portion</b> of the AST
  + * responsible for producing dynamic content at the
  + * injection point.
  + *
  + * The Injector when called to fill in the preparsed
  + * template at the injection point by using a visitor
  + * to walk over the small portion of AST that is held
  + * in this object.
  + *
  + * For example, some dynamic content might be generated
  + * like this:
  + *
  + * #foreach $element in $list
  + * {
  + *     This is the $element.
  + * }
  + *
  + * Now the AST for this small portion of the template
  + * may be represented like this (this was generated by
  + * the DumpVisitor):
  + *
  + * ForeachStatement
  + *  Block
  + *   Text
  + *   Text
  + *   Text
  + *   Variable
  + *   Text
  + *
  + * So to generate content at the injection point
  + * the Injector makes a visitor walk the little
  + * block listed above, the resultant content
  + * is placed into the preparsed template by
  + * the injector.
  + *
  + * So only where there is dynamic content will
  + * an Injector be used, all nodes that produced
  + * static text nodes by the original parsing
  + * process will be stored in the preparsed
  + * format. While all dynamic content locations
  + * or injection points will be stored and filled
  + * in when a request for the template is made.
  + *
  + * I still haven't thought about how to somehow
  + * store static portions within a dynamically
  + * generation section. Like above, it is a #foreach
  + * directive but there are static text nodes
  + * within. I'm not sure what performance impact
  + * might be gained by trying to store those
  + * static nodes. But if you had a very large
  + * $list to pass through the gain might be
  + * considerable. Regardless I haven't given
  + * it much thought other then it is a possible
  + * point of optimization.
  + *
  + * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
  + * @version $Id: Injector.java,v 1.3 2000/08/27 22:59:06 jvanzyl Exp $
  + */
  +public abstract class Injector
   {
  -    public void inject();
  +    /** Where in the stream to inject this objects content */
  +    protected int injectionLocation;
  +    /** Context to build against */
  +    protected Context context;
  +    /**
  +     * The root node of the _portion_ of the AST
  +     * responsible for producing dynamic content
  +     * this injector's location.
  +     */
  +    protected SimpleNode root;
  +    /** 
  +     * The visitor used by the injector to generate
  +     * dynamic content.
  +     */
  +    protected InjectorVisitor visitor;
  +
  +    // Actually we can reuse the visitor created by
  +    // the template. So we can probably save the
  +    // expense of visitor creation ... we just
  +    // need access to the Template.
  +    
  +    // Same actually goes for the context, we can
  +    // just grab it from the Template. Sweet.
  +
  +    // And we probably don't need all these different
  +    // types of injectors if we are going to reuse
  +    // the visitor code. I'll leave things here for
  +    // now. All we really need now in a concrete
  +    // Injector.
  +
  +    public void inject()
  +    {
  +    }
  +    
  +    public void setContext(Context context)
  +    {
  +        this.context = context;
  +    }        
  +
  +    
   }