Page (MollyPages.org Foundation API)

All Known Implementing Classes:

PageImpl
```
public interface Page
```
A page is a cool and sane replacement for JSP's with much better syntax.
Server side pages implement this interface via the concrete PageImpl class. This class has some additional utility methods as well that page authors may find useful.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`DEFAULT_BUFFER_SIZE`
`static String`	`DEFAULT_ENCODING` The default encoding of the page, specified in the header sent back to the client.
`static String`	`DEFAULT_MIME_TYPE` The default mime-type for each page.
`static String`	`DEFAULT_SRC_ENCODING` Used when compiling a page using javac.
`static String`	`PACKAGE_NAME`

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`void`	`clientRedirect(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, String newLocation)` Redirects the client to the new page location.
`void`	`destroy()` This method is invoked whenever a page is destoryed/unloaded
`String`	`getPagePath(javax.servlet.http.HttpServletRequest req)` Returns the path to this page from the web servers document root.
`String`	`getRealPath(javax.servlet.http.HttpServletRequest req)` Returns the real absolute directory path for the `PagePath`.
`CharArrayWriter`	`getThreadLocalWriter()` Returns a thread specific CharArrayWriter that can be passed to this method as various points in the page.
`void`	`init(PageServlet servlet, String contextRelativePagePath)` This method is invoked whenever a page is created and before it is run.
`void`	`render(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)`

Field Detail
- PACKAGE_NAME
```
static final String PACKAGE_NAME
```
  See Also:
  
  Constant Field Values
- DEFAULT_BUFFER_SIZE
```
static final int DEFAULT_BUFFER_SIZE
```
  See Also:
  
  Constant Field Values
- DEFAULT_MIME_TYPE
```
static final String DEFAULT_MIME_TYPE
```
  The default mime-type for each page. Usually, there should be no reason to change this. However, if need be, this can be changed via a page compiler directive or turned off entirely. If it's turned off, then the mime-type should be manually specified via the javax.servlet.ServletResponse.setContentType method.
  
  See Also:
  
  Constant Field Values
- DEFAULT_ENCODING
```
static final String DEFAULT_ENCODING
```
  The default encoding of the page, specified in the header sent back to the client. This can be changed to utf-8, utf-16 or any other coding by a page directive. Alternately, this can be set to an empty string and a different encoding can also be specified in the <head> section of the html document, for example:
```
<head><meta http-equiv=content-type content='text/html; charset=UTF-8'></head>
```
  Encodings can be tricky. We are first compiling a page into a java source file, then running the source file and sending it's output to the browser. Read the page encoding and charsets if you are using any non-us-ascii or non-ISO-8859-1 characters in your molly source page.
  See Also:
  
  Constant Field Values
- DEFAULT_SRC_ENCODING
```
static final String DEFAULT_SRC_ENCODING
```
  Used when compiling a page using javac.
  If no src_encoding directive is present in the page, we use UTF-8 is the best modern way of doing this (ISO-8859-1 is obsolete and ISO-8859-1 documents can run into issues with javac (which may default to UTF-8 on modern platforms if not specified and umlauts/diacritics/accents are in UTF-8 and ISO-8859-1).
  
  See Also:
  
  Constant Field Values

Method Detail

render

void render(javax.servlet.http.HttpServletRequest req,
            javax.servlet.http.HttpServletResponse res)
     throws Exception

Throws:: Exception

init
```
void init(PageServlet servlet,
          String contextRelativePagePath)
   throws javax.servlet.ServletException
```
This method is invoked whenever a page is created and before it is run.
Pages should override this method to instantiate/set-up page variables as needed. (pages have no-arg constructors so like most of the servlet API, setup and initialization of variables is done in a init method instead).
When overriding this class, you must remember to call: super.init
The page class is reloaded if the page is modified. Variables should therefore be cleaned up in the destory method as needed.

Throws:

javax.servlet.ServletException

destroy
```
void destroy()
```
This method is invoked whenever a page is destoryed/unloaded

getPagePath
```
String getPagePath(javax.servlet.http.HttpServletRequest req)
```
Returns the path to this page from the web servers document root.
So for example, if the page is at foo/bar.mp and is running under the webapp context of context1, then the page path will be: /context1/foo/bar.mp. If there is no specific web app (i.e., the most common case of a default "" webapp), then the page path will be /foo/bar.mp
This page path is essentially what needs to be typed in the browsers URL window to invoke the page. It's also useful as form action parameters. For example, in a molly page:
```
..
<form action="[=getPagePath(req)]" method="post">
..
</form>
```
This will submit the form to the same page where the form is defined. This can be hard coded of course but by using getPagePath, the html does not have to be changed if the name of the page changes on disk.

getRealPath
```
String getRealPath(javax.servlet.http.HttpServletRequest req)
```
Returns the real absolute directory path for the PagePath.
So, for example, for a webserver document root at /web/sites/default/ and a page located in foo/bar.mp, the real path will be: /web/sites/default/foo/bar.mp

clientRedirect

void clientRedirect(javax.servlet.http.HttpServletRequest req,
                    javax.servlet.http.HttpServletResponse res,
                    String newLocation)
             throws IOException

Redirects the client to the new page location. This is a thin (possibly easier to remember) wrapper around the HttpServletResponse.sendRedirect method.

The location parameter can be relative to the specified request's URI or relative to the context root if it contains a leading '/'. The webapp name (if any) does not have to be specified, the redirect will creates a full URL (including the webapp context path) suitable for this purpose.

For example:

webapp context	current page	location parameter	resulting page
default web app ("/")	foo/bar.mp	baz.mp	foo/baz.mp
default web app ("/")	foo/bar.mp	/baz.mp	baz.mp
/myapp	foo/bar.mp	baz.mp	/myapp/foo/baz.mp
/myapp	foo/bar.mp	/baz.mp	/myapp/baz.mp

Parameters:: req - the current request; res - the current response; location - location to redirect to.
Throws:: IOException

getThreadLocalWriter
```
CharArrayWriter getThreadLocalWriter()
```
Returns a thread specific CharArrayWriter that can be passed to this method as various points in the page. The contents of this writer can then be printed on the page when desired.
Note: The writer is not reset or flushed when it is retrieved. It must be reset manually via calling the CharArrayWriter.reset() method. This design-decision allows request threads to collect debugging data across multiple pages.
The suggested usage idiom is:
```
  dbg(true);
  CharArrayWriter cw = getThreadLocalWriter():
  bug(cw, "some message");
  ...
  bug(cw, "other message");
  ...
  
  cw.writeTo(out);
  cw.reset();
  
```

Interface Page

Field Summary

Method Summary

Field Detail

PACKAGE_NAME

DEFAULT_BUFFER_SIZE

DEFAULT_MIME_TYPE

DEFAULT_ENCODING

DEFAULT_SRC_ENCODING

Method Detail

render

init

destroy

getPagePath

getRealPath

clientRedirect

getThreadLocalWriter