Glossary 关键字

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2023-12-01

Attribute(属性)

为了连接 XML 或HTML (或通用的 SGML)，属性是关联元素的命名的值。比如，在 <body bgcolor=black text=green>...</body>中，属性是 bgcolor=black 和 text=green。在符号 = 的左边是属性的名字，而在右边的是属性的值。注意在XML中，值必须是被引号引起来的(比如：<body bgcolor="black" text='green'>)，而在HTML中它对某些值是可选的。

See Also Start-tag

Environment

An Environment object stores the runtime state of a single template template processing job. That is, for each Template.process(...) call, an Environment instance will be created, and then discarded when process returns. This object stores the set of temporary variables created by the template, the value of settings set by the template, the reference to the data-model root, etc. Everything that is needed to fulfill the template processing job.

Extensible Markup Language

A subset (restricted version) of SGML. This is less powerful than SGML, but it easier to learn and much easier to process with programs. If you are an HTML author: XML documents are similar to HTML documents, but the XML standard doesn't specify the usable elements. XML is a much more general-purpose thing than HTML. For example you can use XML to describe Web pages (like HTML) or to describe non-visual information like a phone book database.

FreeMarker Template Language

Simple programming language designed to write text file templates, especially HTML templates.

FTL

See FreeMarker Template Language

FTL tag

Tag-like text fragment used to invoke FreeMarker directives in FTL templates. These are similar to HTML or XML tags at the first glance. The most prominent difference is that the tag name is started with # or @. Another important difference is that FTL tags do not use attributes, but a substantially different syntax to specify parameters. Examples of FTL tags: <#if newUser>, </#if>, <@menuitem title="Projects" link="projects.html"/>

Full-qualified name(完全限定名)

... 对于结点来说(XML结点或其它FTL结点变量)：结点的完全限定名不仅仅指定结点名称 (node?node_name)，而且指定结点的命名空间 (node?node_namespace)，这种方式明确地指出结点的确定类型。完全限定名的格式是 nodeName 或 prefix:nodeName。前缀是识别结点命名空间(结点的命名空间通常是使用很长的URI来指定的)的速记形式。在FTL中，前缀使用ftl 指令的 ns_prefixes 参数和结点的命名空间相关联。在XML文件中，前缀使用 xmlns:prefix 属性和结点的命名空间相关联。如果默认的命名空间被定义了，缺少前缀说明结点使用默认的命名空间；否则就说明结点不属于任何结点命名空间。 FTL中定义的默认结点命名空间通过使用 ftl 指令的 ns_prefixes 参数来注册保留前缀 D。在XML文件中，使用属性 xmlns 来定义。

... 对于Java类来说：Java类的完全限定名包含类名和所属包的名字。这种方式明确地指出了类，而不管其内容。类的完全限定名示例： java.util.Map (和 Map相对)。

Hash

A variable that acts as a container that stores sub variables that can be retrieved via a string that is a lookup name.

See Also Sequence

Line break

Line break is a special character (or a sequence of special characters) that causes a line breaking when you see the text as plain text (say, when you read the text with Windows notepad). Typically you type this character by hitting ENTER or RETURN key. The line break is represented with different characters on different platforms (to cause incompatibility and confusion...): ``line feed'' character on UNIX-es, ``carriage return'' character on Macintosh, ``carriage return''+``line feed'' (two characters!) on Windows and DOS. Note that line breaks in HTML do not have a visual effect when viewed in a browser; you must use markup such as <BR> for that. This manual never means <BR> when it says ``line-break''.

Macro definition body

The template fragment between the <#macro ...> and </#macro>. This template fragment will be executed when you call the macro (for example as <@myMacro/>).

Method

A variable that calculates something based on parameters you give, and returns the result.

MVC pattern

MVC stands for Model View Controller. It's a design pattern started his life in the 70's as a framework developer by Trygve Reenskaug for Smalltalk, and was used primary for for UI-s (user interfaces). MVC considers three roles:

Model: Model represents application (domain) specific information in a non-visual way. For example, an array of product objects in the memory of your computer is the part of the model.
View: View displays the model and provides UI. For example, it's the task of the view component to render the array of product objects to a HTML page.
Controller: The controller handles user input, modifies the model, and ensures that the view is updated when needed. For example it is the task of controller to take the incoming HTTP requests, parse the received parameters (forms), dispatch the requests to the proper business logic object, and chose the right template for the HTTP response.

The most important thing for us when applying MVC for Web applications is the separation of View from the other two roles. This allows the separation of designers (HTML authors) from programmers. Designers deal with the visual aspects, programmers deal with the application logic and other technical issues; everybody works on what he is good at. Designers and programmers are less dependent on each other. Designers can change the appearance without programmers having to change or recompile the program.

For more information I recommend reading chapter 4.4 of Designing Enterprise Applications with the J2EE Platform blueprint.

Output encoding

Means output charset. In the Java world the term ``encoding'' is commonly (mis)used as a synonym to ``charset''.

Predefined directive

Directive what is defined by FreeMarker, thus always available. Example of predefined directives: if, list, include