Parts of an Enterprise Composer

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The Enterprise Composer has five parts.

• The Parts tree
• Title
• Contextual help
• Property sheet
• Menu bar

The Parts tree shows the structure of the currently open Servlets in a tree view. Parts may be dragged from one part of the tree to another, including the recycling bin. Parts may also be dragged from the Palette to appropriate parts of the tree. The Parts tree will not allow all parts to be moved; parts which represent fundamental aspects of a Servlet cannot be moved. Likewise, parts which can be moved may only be moved to appropriate locations. The tree will display a cancel icon if the part may not be moved to a location. The nodes of the tree may be collapsed or expanded to aid in navigation. The amount of space devoted to the tree may adjusted by dragging the separator bar.

Parts are selected by clicking on them in the Parts tree. When a part is selected in the Parts tree, it is highlighted in the tree. In addition, the name of the part is shown in the title area, the contextual help for that part is displayed, and the property sheet for the part is displayed.

There are two special nodes which are always in the Parts tree: the Recycling Bin and the Copier. The Recycling Bin is where parts may be dragged which will be destroyed. It can also be used as a temporary holding place to store parts apart from their Servlet. Parts in the Recycling Bin should not be edited.

Drag parts that you want to copy to the Copier. The original part being dragged will not be affected, but an exact copy of that part will be added to the Copier. This is a quick way to make temporary backups of parts before making any significant changes to the originals. It is also useful if you want to put a copy of a part into a different Servlet. Parts in the Copier should not be edited.

In addition to these two nodes, there will always be at least one Enterprise Servlet in the Parts tree. The Enterprise Servlet is the top node for a Servlet. It has several properties that can be modified. These properties are discussed on page 64.

The contextual help area is a scrollable area which displays help about the part which is currently selected in the Parts tree.

The Property sheet for whichever node is currently selected is displayed in the lower portion of the composer window. The properties of a part can be set in the Property sheet.

Property sheets may consist of code areas. The user can enter any legal Java statements in these code areas. Simplicity watches for any changes made and updates the Servlet so that any servlet request responds in a fashion that always reflects the current state of the code. If an import statement is entered in a code event area, it will be moved to the proper place in the generated code.

At the top of every code area is a Code Sourcerer button. The Code Sourcerer will write Java statements for the user based upon the user's choices. Some code pages will generate code inside a method statement. For example, the Exception Handler code area will allow users to write code inside the exceptionHander method. This method has a five local variables, 'ex', 'moduleName', 'methodName', 'comment' and 'registry', available to it. The Sourcerer's Apprentice (page 93) is also available in code areas.