There are cases when web files cannot or do not have to specify certain properties within the content of the file. For example, before XHTML, it was not necessarily required to specify the DOCTYPE within an html file. Or in JSP Fragments, page directives and such are not in the fragments themselves. Without this information, however, some features such as content assist and source validation cannot work to the best of their knowledge. So there needs to be a way to associate the invisible information. File properties can be used to associate additional information with file. The file properties work like per-file/per-project preferences, and they are visible via the Properties Dialog.

The Structured Source Editing component currently contributes 3 property pages:

• jst.jsp
  JSP Fragment Content Settings
• wst.html
  Web Content Settings
• wst.css
  (CSS) Web Content Settings

Note: Currently changes to the file properties do not take effect immediately in a file that is already open in an editor. Users must close and reopen the file for the new settings to take effect.

Users can use the JSP Fragment property page to specify the scripting language and content type that should be associated with the JSP fragment. Users can also specify if they want the fragment validated or not (the fragment will be validated like a JSP).

Users can use the Web Content Settings property page to specify the default document type to be used if none is specified in the file. They can also specify the type of CSS they plan on using.

Users can use the (CSS) Web Content Settings property page to specify the type of CSS they plan on using.

The properties are currently stored with the project they are associated with. This way, the properties travel along with the project, so when projects are shared amongst a team, so are the properties. The properties are stored as project preferences. Project preferences are stored in a .settings folder under the project root.

Clients should already have the properties specified and accessible via an existing mechanism, like the PageDirectiveAdapter or HTMLDocumentTypeAdapter. It is then up to the PageDirectiveAdapter and HTMLDocumentTypeAdapter to call the appropriate code below to get the information desired.
For the curious, PageDirectiveAdapter ahd HTMLDocumentAdapter will then in turn call a get or set Property method call in the desired xxxContentProperties class to get the information they need.

/**
 * Returns the value for the given key in the given context.
 * 
 * @param key
 *            The property key
 * @param resource
 *            The current context or null if no context is
 *            available and the workspace setting should be taken. Note
 *            that passing null should be avoided.
 * @param recurse
 *            whether the parent should be queried till property is found
 * @return Returns the current value for the key.
 * @since 1.1
 */
public static String getProperty(String key, IResource resource, boolean recurse)


/**
 * Sets the value for the given key in the given context.
 * 
 * @param key
 *            The property key
 * @param resource
 *            The current context. Note context cannot be
 *            null.
 * @param value
 *            The value to set for the key. If value is null
 *            the key is removed from properties.
 * @since 1.1
 */
public static void setProperty(String key, IResource resource, String value) throws CoreException

• JSP Fragment properties (org.eclipse.jst.jsp.core.internal.contentproperties.JSPFContentProperties)
  JSPCONTENTTYPE - default content type for JSP Fragments
  JSPLANGUAGE - default language for JSP Fragments
  VALIDATE_FRAGMENTS - whether or not to validate JSP Fragment
• HTML properties (org.eclipse.wst.html.core.internal.contentproperties.HTMLContentProperties)
  DOCUMENT_TYPE - default content type for HTML when DOCTYPE is not specified
• CSS properties(org.eclipse.wst.css.core.internal.contentproperties.CSSContentProperties)
  CSS_PROFILE - css profile to use