Package lazyj

Class ExtendedServlet

java.lang.Object
javax.servlet.GenericServlet
javax.servlet.http.HttpServlet
lazyj.ExtendedServlet
All Implemented Interfaces:
Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig, javax.servlet.SingleThreadModel
public abstract class ExtendedServlet extends javax.servlet.http.HttpServlet implements javax.servlet.SingleThreadModel
Probably the most important class in the world :)

This class is a wrapper over the original HttpServlet, adding caching and run time limit for the servlets. There are also other useful functions, like initMultipartRequest(String, int) for uploading files, getX (s/i/f/d) for parsing the parameters and getting the correct value, getCookie(String), setCookie(String, String), log(int, String)
Since:
2006-10-02
Author:
costing
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected boolean
    bGet
    Servlets can treat GET and POST differently based on the method they override or by looking at this variable
    protected boolean
    bRedirect
    Remember whether or not there was a redirect executed by the servlet
    DBSession
    dbs
    Current session
    static final long
    lServerStarted
    This is when the server was started
    protected com.oreilly.servlet.MultipartRequest
    mpRequest
    Object used for file uploading.
    protected OutputStream
    osOut
    OutputStream to the client
    protected PrintWriter
    pwOut
    PrintWriter to the client.
    protected javax.servlet.http.HttpServletRequest
    request
    The original request object
    protected javax.servlet.http.HttpServletResponse
    response
    The original response object
    protected String
    sPage
    Current servlet that is executed
    protected String
    sZone
    The zone of the currently executed servlet

  • Constructor Summary

    Constructors
    Constructor
    Description
    ExtendedServlet()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    final void
    doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)
    Original request from servlet engine comes through here.
    protected void
    doInit()
    This is a hook provided for the servlets as a generic way to initialize their local variables, do authentication and so on.
    final void
    doPost(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)
    Original request from servlet engine comes through here.
    static final String
    esc(String s)
    Produce safe SQL strings.
    static final String
    escHtml(String s)
    Produce save HTML strings.
    abstract void
    execGet()
    A servlet must implement at least this method.
    void
    execPost()
    By default POST request are executed with the same execGet() function.
    protected int
    getApp()
    Get the application number.
    final boolean
    getb(String sParam, boolean defaultValue)
     
    static final long
    getCacheAccesses()
    Statistics: get the total number of accesses to pages that could be cached
    static final long
    getCacheHits()
    Statistics: get the number of cache hits
    protected String
    getCacheKeyModifier()
    Override this method to return any value that would alter the cache.
    protected long
    getCacheTimeout()
    Method to specify the maximum life time of the cached contents.
    final String
    getCookie(String sName)
    Get the value of a specific cookie
    final String
    getCurrentPage()
    Compose the full URL to the current page.
    final double
    getd(String sParam)
    Get the value of a parameter as a double value.
    final double
    getd(String sParam, double defaultVal)
    Get the value of a parameter as a double value.
    protected String
    getDomain()
    Method to specify the domain for which the cookies will be set by default (session cookie included).
    final float
    getf(String sParam)
    Get the value of a parameter as a float value.
    final float
    getf(String sParam, float defaultVal)
    Get the value of a parameter as a float value.
    static final long
    getFrameworkRequests()
    Framework statistics: get the total number of requests serviced by the framework.
    final String
    getHostAddr()
    Get the client host address (IP).
    final String
    getHostName()
    Get the nice host name for the client that made the current request.
    final int
    geti(String sParam)
    Get the value of a parameter as an integer value.
    final int
    geti(String sParam, int defaultVal)
    Get the value of a parameter as an integer value.
    final long
    getl(String sParam)
    Get the value of a parameter as a long value.
    final long
    getl(String sParam, long defaultVal)
    Get the value of a parameter as a long value.
    protected int
    getMaxRunTime()
    Method to specify the maximum run time for a page.
    protected int
    getOnlineUsers()
    Get the number of online users for the current application.
    final String
    gets(String sParam)
    Get the value of a parameter as a string.
    final String
    gets(String sParam, String sDefault)
    Get the value of a parameter as a string.
    static final String
    getServerUptime()
    Statistics: get the server uptime
    final String[]
    getValues(String sParam)
    Get all the values of a parameter.
    protected final boolean
    initMultipartRequest(String sTempDir, int iFileSizeLimit)
    This method should be called when the servlet expects a file upload from the client.
    boolean
    isLoggable(int iLevel)
    Find out whether or not the current page is able to log this level of debug.
    boolean
    isSessionIPProtected()
    Flag to set whether or not the session is valid only when used from the first IP that generated the session.
    void
    log(int level, String sMessage)
    Log messages with a given level of the problem.
    void
    log(int level, String sMessage, Object o)
    Special logging for exceptions.
    void
    log(String sMessage)
    Override the method provided by the Java Servlet Api to log messages as DEBUG
    protected final boolean
    redirect(String sURL)
    Wrapper method for the actual redirect, that keeps track if there was such an opperation.
    void
    setContentType(String sContentType)
    If you set the content type to something else than "text/html; charset=UTF-8" and you use the caching mechanism you should use this method instead of directly calling response.setContentType
    boolean
    setCookie(String sName, String sValue)
    Send a session cookie to the browser.
    boolean
    setCookie(String sName, String sValue, int iAge)
    Send a cookie to the browser.
    boolean
    setCookie(String sName, String sValue, String sDomain, int iAge)
    Send a cookie to the browser.
    protected void
    zoneInit()
    Override this function to initialize local servlet or zone variables (pMaster for example)

    Methods inherited from class javax.servlet.http.HttpServlet

    doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

    Methods inherited from class javax.servlet.GenericServlet

    destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • lServerStarted

      public static final long lServerStarted
      This is when the server was started

    • request

      protected javax.servlet.http.HttpServletRequest request
      The original request object

    • response

      protected javax.servlet.http.HttpServletResponse response
      The original response object

    • osOut

      protected OutputStream osOut
      OutputStream to the client

    • pwOut

      protected PrintWriter pwOut
      PrintWriter to the client. Same as osOut, but other interface

    • sPage

      protected String sPage
      Current servlet that is executed

    • sZone

      protected String sZone
      The zone of the currently executed servlet

    • mpRequest

      protected com.oreilly.servlet.MultipartRequest mpRequest
      Object used for file uploading. See initMultipartRequest(String, int).

    • bRedirect

      protected boolean bRedirect
      Remember whether or not there was a redirect executed by the servlet

    • bGet

      protected boolean bGet
      Servlets can treat GET and POST differently based on the method they override or by looking at this variable

    • dbs

      public DBSession dbs
      Current session

  • Constructor Details

    • ExtendedServlet

      public ExtendedServlet()

  • Method Details

    • getCacheKeyModifier

      protected String getCacheKeyModifier()
      Override this method to return any value that would alter the cache. Usually you will want to return here the username, if the user is logged. Or the value of some cookie, if it alters the contents of the caching ...
      Returns:
      some string that is appended to the caching key.

    • getCacheAccesses

      public static final long getCacheAccesses()
      Statistics: get the total number of accesses to pages that could be cached
      Returns:
      the total number of pages served through this framework

    • getCacheHits

      public static final long getCacheHits()
      Statistics: get the number of cache hits
      Returns:
      the number of pages served from a memory cache by this framework

    • getServerUptime

      public static final String getServerUptime()
      Statistics: get the server uptime
      Returns:
      Server uptime, as formatted string

    • getFrameworkRequests

      public static final long getFrameworkRequests()
      Framework statistics: get the total number of requests serviced by the framework.
      Returns:
      total number of requests to servlets that extend the framework

    • getCacheTimeout

      protected long getCacheTimeout()
      Method to specify the maximum life time of the cached contents. You should override this method to return the number of seconds for which you know that the contents will not change and it's safe to serve the users the same contents.

      This method returns 0 in the default implementation, meaning that the caching is by default disabled for all the servlets.
      Returns:
      number of seconds for which the contents is valid, default is 0 (cache disabled)

    • getDomain

      protected String getDomain()
      Method to specify the domain for which the cookies will be set by default (session cookie included). You should override this method to return something like ".acasa.ro".
      Returns:
      the domain for which the cookies will be set by default

    • getMaxRunTime

      protected int getMaxRunTime()
      Method to specify the maximum run time for a page. After this much time (in seconds) the thread that runs the page is forcefully killed. Override this method if you want to allow a maximum execution time different than the default 60 seconds.

      In special (read very very unlikely cases) you can return 0 to disable the threads monitoring. This means that this thread is allowed to run forever, and if it does something bad, nobody will catch it. So, you've been warned ...
      Returns:
      the maximum run time, in seconds, for the current page.

    • execGet

      public abstract void execGet()
      A servlet must implement at least this method.

    • execPost

      public void execPost()
      By default POST request are executed with the same execGet() function. If you want to execute a different code on POST than on GET you can override this function or you can check the bGet variable.

    • getApp

      protected int getApp()
      Get the application number. Each major application should have a different, unique, identifier. This is to distinguish between the sessions, which ones are for which application, when creating statistics. See getOnlineUsers() for example.
      Returns:
      application unique number

    • isSessionIPProtected

      public boolean isSessionIPProtected()
      Flag to set whether or not the session is valid only when used from the first IP that generated the session. In some cases (multiple load-balancing http proxies) this schema might not work.
      Returns:
      true by default, but can be overriden by actual implementations

    • setContentType

      public void setContentType(String sContentType)
      If you set the content type to something else than "text/html; charset=UTF-8" and you use the caching mechanism you should use this method instead of directly calling response.setContentType
      Parameters:
      sContentType -

    • gets

      public final String gets(String sParam)
      Get the value of a parameter as a string.
      Parameters:
      sParam - the parameter name
      Returns:
      the string value of this parameter, never null ("" is returned in the worst case)

    • gets

      public final String gets(String sParam, String sDefault)
      Get the value of a parameter as a string.
      Parameters:
      sParam - the parameter name
      sDefault - default value to return in case the value is not defined or is the empty string
      Returns:
      the string value of this parameter

    • geti

      public final int geti(String sParam, int defaultVal)
      Get the value of a parameter as an integer value. If there is a parsing error then return the given default value.
      Parameters:
      sParam - the name of the parameter
      defaultVal - default value to return in case of an error
      Returns:
      parsed value of the parameter, or the defaultValue if parameter is missing or is not an integer value representation

    • geti

      public final int geti(String sParam)
      Get the value of a parameter as an integer value. If there is a parsing error then the value 0 will be returned.
      Parameters:
      sParam - name of the parameter
      Returns:
      parsed value of the request parameter, or 0 if there is any error in parsing, parameter not existing etc

    • getl

      public final long getl(String sParam, long defaultVal)
      Get the value of a parameter as a long value. If there is a parsing error then return the given default value.
      Parameters:
      sParam - the name of the parameter
      defaultVal - default value to return in case of an error
      Returns:
      parsed value of the parameter, or the defaultValue if parameter is missing or is not a long value representation

    • getl

      public final long getl(String sParam)
      Get the value of a parameter as a long value. If there is a parsing error then the value 0 will be returned.
      Parameters:
      sParam - name of the parameter
      Returns:
      parsed value of the request parameter, or 0 if there is any error in parsing, parameter not existing etc

    • getf

      public final float getf(String sParam, float defaultVal)
      Get the value of a parameter as a float value. If there is a parsing error then return the given default value.
      Parameters:
      sParam - the name of the parameter
      defaultVal - default value to return in case of an error
      Returns:
      parsed value of the parameter, or the defaultValue if parameter is missing or is not a float value representation

    • getf

      public final float getf(String sParam)
      Get the value of a parameter as a float value. If there is a parsing error then the value 0 will be returned.
      Parameters:
      sParam - name of the parameter
      Returns:
      parsed value of the request parameter, or 0 if there is any error in parsing, parameter not existing etc

    • getd

      public final double getd(String sParam, double defaultVal)
      Get the value of a parameter as a double value. If there is a parsing error then return the given default value.
      Parameters:
      sParam - the name of the parameter
      defaultVal - default value to return in case of an error
      Returns:
      parsed value of the parameter, or the defaultValue if parameter is missing or is not a double value representation

    • getd

      public final double getd(String sParam)
      Get the value of a parameter as a double value. If there is a parsing error then the value 0 will be returned.
      Parameters:
      sParam - name of the parameter
      Returns:
      parsed value of the request parameter, or 0 if there is any error in parsing, parameter not existing etc

    • getValues

      public final String[] getValues(String sParam)
      Get all the values of a parameter.
      Parameters:
      sParam -
      Returns:
      values array, possibly empty but never null

    • getb

      public final boolean getb(String sParam, boolean defaultValue)
      Parameters:
      sParam -
      defaultValue -
      Returns:
      the boolean value of this parameter

    • redirect

      protected final boolean redirect(String sURL)
      Wrapper method for the actual redirect, that keeps track if there was such an opperation. This is done in order to disable the caching in this case.
      Parameters:
      sURL - the URL to send the browser to
      Returns:
      true if the operation was successfully, false if there was an error

    • esc

      public static final String esc(String s)
      Produce safe SQL strings. Wrapper for Format.escSQL(String) call.
      Parameters:
      s - the string to escape
      Returns:
      the SQL-safe representation

    • escHtml

      public static final String escHtml(String s)
      Produce save HTML strings. Wrapper for Format.escHtml(String) call.
      Parameters:
      s - the string to escape
      Returns:
      the HTML-safe representation

    • getCookie

      public final String getCookie(String sName)
      Get the value of a specific cookie
      Parameters:
      sName - the name of the cookie
      Returns:
      the value of the cookie, or "" if there was an error (cookie not existing ...)

    • setCookie

      public boolean setCookie(String sName, String sValue)
      Send a session cookie to the browser. The cookie is made available to the domain returned by the getDomain() function
      Parameters:
      sName - name of the cookie
      sValue - value
      Returns:
      true on success, false on error

    • setCookie

      public boolean setCookie(String sName, String sValue, int iAge)
      Send a cookie to the browser. The cookie is made available to the domain returned by the getDomain() function
      Parameters:
      sName - name of the cookie
      sValue - value
      iAge - lifetime of the cookie, in seconds, relative to "now". Negative=session cookie. Zero=delete this cookie.
      Returns:
      true on success, false on error

    • setCookie

      public boolean setCookie(String sName, String sValue, String sDomain, int iAge)
      Send a cookie to the browser.
      Parameters:
      sName - name of the cookie
      sValue - value
      sDomain - the domain for which this cookie is set
      iAge - lifetime of the cookie, in seconds, relative to "now". Negative=session cookie. Zero=delete this cookie.
      Returns:
      true on success, false on error

    • doInit

      protected void doInit()
      This is a hook provided for the servlets as a generic way to initialize their local variables, do authentication and so on. Generally this is implemented in each zone's local master servlet and checks for user's session. You probably want to override this. Use this to initialize only the variables used in getCacheTimeout() and getCacheKeyModifier(). For IO-related variables (eg pMaster) use zoneInit().

    • zoneInit

      protected void zoneInit()
      Override this function to initialize local servlet or zone variables (pMaster for example)

    • doGet

      public final void doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)
      Original request from servlet engine comes through here. It will be handled internally.
      Overrides:
      doGet in class javax.servlet.http.HttpServlet
      Parameters:
      req - servlet request
      resp - servlet response

    • doPost

      public final void doPost(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)
      Original request from servlet engine comes through here. It will be handled internally.
      Overrides:
      doPost in class javax.servlet.http.HttpServlet
      Parameters:
      req - servlet request
      resp - servlet response

    • initMultipartRequest

      protected final boolean initMultipartRequest(String sTempDir, int iFileSizeLimit)
      This method should be called when the servlet expects a file upload from the client. It will initialize the mpRequest object. If the file is too big or there is another problem uploading the file then the method will return false, if everything is ok then it will return true.
      Parameters:
      sTempDir - temporary folder for the files that are uploaded
      iFileSizeLimit - maximum size of a file
      Returns:
      true if the request is indeed a file upload, the file size is <= iFileSizeLimit and the weather outside is fine

    • getOnlineUsers

      protected int getOnlineUsers()
      Get the number of online users for the current application. See getApp() for this.
      Returns:
      the number of online users (active sessions)

    • getHostName

      public final String getHostName()
      Get the nice host name for the client that made the current request. If possible this will return the reversed DNS name, or if this is not available the plain IP address.
      Returns:
      client's address

    • getHostAddr

      public final String getHostAddr()
      Get the client host address (IP).
      Returns:
      the client's IP address

    • getCurrentPage

      public final String getCurrentPage()
      Compose the full URL to the current page. Use this when you want for example to force the user to first authenticate, and when this operation succeeds to return it to the page it was initially trying to access.
      Returns:
      the URL of the current page
      See Also:

    • log

      public void log(String sMessage)
      Override the method provided by the Java Servlet Api to log messages as DEBUG
      Overrides:
      log in class javax.servlet.GenericServlet
      See Also:

    • log

      public void log(int level, String sMessage)
      Log messages with a given level of the problem. See Log for possible logging levels.
      Parameters:
      level - problem level
      sMessage - error message

    • log

      public void log(int level, String sMessage, Object o)
      Special logging for exceptions. It can be used to log any other objects too, but if the passed object is not a Throwable instance it will simply call toString() for it and that's it.
      Parameters:
      level - problem level
      sMessage - error message
      o - object to be logged, special case when the object is a Throwable instance

    • isLoggable

      public boolean isLoggable(int iLevel)
      Find out whether or not the current page is able to log this level of debug. You should check for this function's result prior to actually logging something big or something that would require some processing power.
      Parameters:
      iLevel - desired logging level
      Returns:
      true if a message at this level would be logged, false if not