Class ListTemplate

java.lang.Object
sunlabs.brazil.template.Template
sunlabs.brazil.sunlabs.ListTemplate
All Implemented Interfaces:
TemplateInterface

public class ListTemplate extends Template
Manage lists of strings in a (hopefully) useful way. A vector is used to store list elements. Attributes to the <list> tag are used to manipulate the list, whereas "smart properties" are used to retrieve list members.
 <list name=x [namespace=xx clear=true|false delete=xx remove=n insert=xx
                  append=xx unique=true|false sort=true|false delim=d
                  overlap=n chunksize=n chunk=n next=true|false previous=true|false]">
 <list name=x ... />
 </list>
 
Access to list elements is only valid between <list>... </list>. See below for details.
  • Constructor Details

    • ListTemplate

      public ListTemplate()
  • Method Details

    • init

      public boolean init(RewriteContext hr)
      Clear any left-over lists.
      Specified by:
      init in interface TemplateInterface
      Overrides:
      init in class Template
    • tag_list

      public void tag_list(RewriteContext hr)
      Process the list tag.
         name=nnn             list name (required)
         namespace=xxxx               namespace for list.  See below
       The following options are processed in order:
         clear=true|false     clear the list if it exists
         delete=xxx  [delim=d]  delete item(s) by value  (items with delimiter d)
         remove  [location=n] remove an item by index (defaults to 0)
         insert=xxx [delim=d] [location=n]
                                      insert item (or items with delimiter=d)
                                      insert in front of element "n" - defaults to 0
         append=xxx [delim=d] append item(s) to the end of the list
         unique=true|false    eliminate all duplicate items
         max=n                        set the maximum size of the list "n"
         sort=true            do a dictionary sort.
         delim=d              set the delimiter for retrieving values
         track=true|false     track all changes to the console
      
       Once a "list" tag is seen, the following properties are
        available (for list foo):
         foo.last     - last item on the list
         for.first    - first item on the list
         foo.count    - number of items on the list
         foo.all      - the entire list
         list.gone    - the last single element removed from the list
         foo.n                - the nth element (0 is the first element)
         foo.n:m      - the range from n-m, inclusive, starting from 0
         foo.ismember.xxx - set to "yes" if "xxx" is in the list
         foo.before.xxx       - the range from 0 till the first occurrance of xxx
         foo.after.xxx        - the range after the 1st occurance of xxx til the end
       
      The first 4 items, above, always appear (for non empty lists) when the properties are enumerated (as with <foreach>

      In the current implementation, "ismember" checks are very fast. However once an "ismember" is accessed, insersion and deletion slows down a bit. Using "clear" will speed up insertion and deletion again.

      If no namespace parameter is provided, the request property [prefix].namespace is used, where [prefix] is Rewrite.templatePrefix. Otherwise the SessionID is used. This results in per-session lists by default. Specifying a namespace allows lists to be shared across sessions.

      An additional set of attributes and properties may be used to manage "chunking", to access a list in pieces for paging. Additional <list> attributes to support chunking:

         overlap=nn           - how many items to overlap between each chunk (default=0)
         chunksize=n          - max items per chunk (default=20)
         chunk=n              - Set the current chunk number (starts at 0)
         next=true|false      - it true, advance to the next page (if available)
         previous=true|false  - it true, advance to the previous page (if available)
       
      None of the above properties change the contents of the list, only how chunks are extracted using the properties below:
         foo.chunk.[n]                - the list of items in chunk "n"
         foo.chunk.chunk      - the current list "chunk" (same as foo.chunk,${foo.chunk.current})
      
         foo.chunk.count      - the number of chunks
         foo.chunk.chunks     - the list of chunks: "0 1 2 ... n"
         foo.chunk.first      - the first chunk number (always 0)
         foo.chunk.before     - the list of chunk numbers before current chunk (if any)
         foo.chunk.previous   - The previous chunk number (if any)
         foo.chunk.current    - The current chunk number
         foo.chunk.next               - The next chunk number (if any)
         foo.chunk.after      - the list of chunk numbers after current chunk
         foo.chunk.last               - the last chunk number
         foo.chunk.size               - The max # of items/chunk
         foo.chunk.overlap    - The current chunk overlap
       
    • tag_slash_list

      public void tag_slash_list(RewriteContext hr)
      remove the most recent list from the current scope.
    • clamp

      public static int clamp(int min, int value, int max)
      Clamp an integer value.
      Parameters:
      min - minimum legal value
      value - the value to clamp
      max - maximum legal value
      Returns:
      "value" clamped between min and max