Examples of org.apache.commons.chain.Command

org.apache.commons.chain.Command
A {@link Command} encapsulates a unit of processing work to beperformed, whose purpose is to examine and/or modify the state of a transaction that is represented by a {@link Context}. Individual {@link Command}s can be assembled into a {@link Chain}, which allows them to either complete the required processing or delegate further processing to the next {@link Command} in the {@link Chain}.

{@link Command} implementations should be designed in a thread-safemanner, suitable for inclusion in multiple {@link Chain}s that might be processed by different threads simultaneously. In general, this implies that {@link Command} classes should not maintain state information ininstance variables. Instead, state information should be maintained via suitable modifications to the attributes of the {@link Context} that ispassed to the execute() command.

{@link Command} implementations typically retrieve and store stateinformation in the {@link Context} instance that is passed as a parameterto the execute() method, using particular keys into the Map that can be acquired via Context.getAttributes(). To improve interoperability of {@link Command} implementations, a useful design pattern is to expose thekey values used as JavaBeans properties of the {@link Command}implementation class itself. For example, a {@link Command} that requiresan input and an output key might implement the following properties:
```
 private String inputKey = "input"; public String getInputKey() { return (this.inputKey); } public void setInputKey(String inputKey) { this.inputKey = inputKey; } private String outputKey = "output"; public String getOutputKey() { return (this.outputKey); } public void setOutputKey(String outputKey) { this.outputKey = outputKey; } 
```
And the operation of accessing the "input" information in the context would be executed by calling:
```
 String input = (String) context.get(getInputKey()); 
```
instead of hard coding the attribute name. The use of the "Key" suffix on such property names is a useful convention to identify properties being used in this fashion, as opposed to JavaBeans properties that simply configure the internal operation of this {@link Command}.
@author Craig R. McClanahan @version $Revision: 1.5 $ $Date: 2004/02/25 00:01:07 $

            pathInfo = request.getPathInfo();
        }


        // Map to the Command specified by the extra path info
        Catalog catalog = (Catalog) context.get(getCatalogKey());
        Command command = catalog.getCommand(pathInfo);
        return (command.execute(context));


    }

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            theCatalog = factory.getCatalog();
        }
        if (attribute == null) {
            request.setAttribute(CATALOG_DEFAULT, theCatalog);
        }
        Command command = theCatalog.getCommand(this.command);
        try {
            command.execute(context);
        } catch (Exception e) {
            throw new ServletException(e);
        }


    }

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        HttpServletRequest request = swcontext.getRequest();
        String value = request.getParameter(getParameter());


        // Map to the Command specified by the extra path info
        Catalog catalog = (Catalog) context.get(getCatalogKey());
        Command command = catalog.getCommand(value);
        return (command.execute(context));


    }

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     *  can be found and the <code>optional</code> property is set
     *  to <code>false</code>
     */
    public boolean execute(Context context) throws Exception {


        Command command = getCommand(context);
        if (command != null) {
            return (command.execute(context));
        } else {
            return (false);
        }


    }

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     *
     * @exception Exception if thrown by the <code>postprocess()</code> method
     */
    public boolean postprocess(Context context, Exception exception) {


        Command command = getCommand(context);
        if (command != null) {
            if (command instanceof Filter) {
                return (((Filter) command).postprocess(context, exception));
            }
        }

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                throw new IllegalArgumentException
                    ("Cannot find catalog '" + catalogName + "'");
            }
        }


        Command command = null;
        String name = getName();
        if (name == null) {
            name = (String) context.get(getNameKey());
        }
        if (name != null) {

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   }


   public void testSetProperty() throws Exception
   {


      Command c = cservice.getCatalog().getCommand("setProperty");
      ctx.put("currentNode", "/test");
      ctx.put("name", "testProperty");
      ctx.put("propertyType", PropertyType.TYPENAME_STRING);
      ctx.put("values", "testValue");
      ctx.put("multiValued", Boolean.FALSE);


      c.execute(ctx);


      System.out.println("> set property>> " + ctx.get("result"));


      Command save = cservice.getCatalog().getCommand("save");
      save.execute(ctx);


   }

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   }


   public void testGetNodes() throws Exception
   {


      Command c = cservice.getCatalog().getCommand("getNodes");
      ctx.put("currentNode", "/");
      c.execute(ctx);


      assertTrue(ctx.get("result") instanceof NodeIterator);
      NodeIterator nodes = (NodeIterator)ctx.get("result");


      // System.out.println("> getNodes >> "+nodes.getSize());

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   }


   public void testAddResourceFile() throws Exception
   {


      Command c = cservice.getCatalog().getCommand("addResourceFile");
      ctx.put("currentNode", "/");
      ctx.put("path", "resource");
      ctx.put("data", "Node data");
      ctx.put("mimeType", "text/html");


      c.execute(ctx);


      System.out.println(">>> Resource >>> " + ctx.get("result"));


      Command save = cservice.getCatalog().getCommand("save");
      ctx.put("path", "/");
      save.execute(ctx);


   }

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   }


   public void testGetNodeChain() throws Exception
   {
      Command cmd = cservice.getCatalog().getCommand("retrieveNodeCommand");
      ctx.put("currentNode", "/");
      ctx.put("path", "test");
      cmd.execute(ctx);


      System.out.println("RESULT >>>>>> " + ctx.get("result"));


   }

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