Head First Servlets and JSP, 2nd Edition

Compression wrapper, helper class code

This helper class is a Decorator on the ServletOutputStream abstract class which delegates the real work of compressing the generated content using a standard GZIP output stream.

There is only one abstract method in the ServletOutputStream that this Decorator must implement: write(int). This is where all of the delegation magic occurs!

Sharpen your pencil

ANSWERS

Write down the sequence in which the filters will be executed for each request path. Assume Filter1 - Filter5 have been properly declared.

<filter-mapping>
  <filter-name>Filter1</filter-name>
  <url-pattern>/Recipes/*</url-pattern>
</filter-mapping>

<filter-mapping>
  <filter-name>Filter2</filter-name>
  <servlet-name>/Recipes/HopsList.do</servlet-name>
</filter-mapping>

<filter-mapping>
  <filter-name>Filter3</filter-name>
  <url-pattern>/Recipes/Add/*</url-pattern>
</filter-mapping>

<filter-mapping>
  <filter-name>Filter4</filter-name>
  <servlet-name>/Recipes/Modify/ModRecipes.do</servlet-name>
</filter-mapping>

<filter-mapping>
  <filter-name>Filter5</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

Request path	Filter Sequence
/Recipes/HopsReport.do	Filters: 1, 5
/Recipes/HopsList.do	Filters: 1, 5, 2
/Recipes/Modify/ModRecipes.do	Filters: 1, 5, 4
/HopsList.do	Filters:5
/Recipes/Add/AddRecipes.do	Filters:1, 3, 5