org.hd.d.pg2k.webSvr.util
Class JavadocBundleServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          org.hd.d.pg2k.webSvr.util.JavadocBundleServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public final class JavadocBundleServlet
extends javax.servlet.http.HttpServlet

This is the servlet that serves the content of the (latest) Gallery javadoc bundle. Essentially this does what the default WAR container support would do if the javadoc files were simply laid out in WAR as static data, though giving us the option to tune cacheing and similar behaviour.

We only respond to GET (and possibly HEAD) requests.

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Serialized Form

fffKey

private static final DataSourceBean.AEPLinkedKey fffKey

Cache key for most frequently-fetched (small) files; never null. Linked to the AEP instance to be automatically discarded when the exhibit set changes.

MAX_FFF_BYTES

private static final int MAX_FFF_BYTES

Maximum uncompressed size in bytes of a file to be considered for the fff cache; strictly positive.

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Constant Field Values

MAX_FFF_BYTES_COMPRESSED

private static final int MAX_FFF_BYTES_COMPRESSED

Maximum compressed size in bytes of a file to be considered for the fff cache; strictly positive.

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Constant Field Values

MIN_FFF_ENTRIES

private static final int MIN_FFF_ENTRIES

Minimum number of entries ('working set') to try to hold in FFF cache; strictly positive. Much smaller than MAX_FFF_ENTRIES, even as small as (say) 10.

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Constant Field Values

MAX_FFF_ENTRIES

private static final int MAX_FFF_ENTRIES

Maximum number of entries to hold in FFF cache; strictly positive. Much larger than MIN_FFF_ENTRIES.

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Constant Field Values

dirKey

private static final DataSourceBean.AEPLinkedKey dirKey

Private key for cache of ZIP directory against current AEP instance; never null.

serialVersionUID

private static final long serialVersionUID

Unique serialisation ID.

See Also:

Constant Field Values

JavadocBundleServlet

public JavadocBundleServlet()

doAction

private void doAction(javax.servlet.http.HttpServletRequest request,
                      javax.servlet.http.HttpServletResponse response,
                      boolean isHEAD)
               throws java.io.IOException

Respond to a GET or HEAD request for the content served by this servlet.

Parameters:

request - The servlet request we are processing

response - The servlet response we are producing

Throws:

java.io.IOException - if an input/output error occurs

doGet

public void doGet(javax.servlet.http.HttpServletRequest request,
                  javax.servlet.http.HttpServletResponse response)
           throws java.io.IOException

Respond to a GET request for the content served by this servlet.

Overrides:

doGet in class javax.servlet.http.HttpServlet

Parameters:

request - The servlet request we are processing

response - The servlet response we are producing

Throws:

java.io.IOException - if an input/output error occurs

doHead

public void doHead(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws java.io.IOException

Respond to a HEAD request for the content served by this servlet.

Overrides:

doHead in class javax.servlet.http.HttpServlet

Parameters:

request - The servlet request we are processing

response - The servlet response we are producing

Throws:

java.io.IOException - if an input/output error occurs

getLastModified

public final long getLastModified(javax.servlet.http.HttpServletRequest request)

Get `last-modified' time for the entire bundle. If we can't find out then we return -1L, the default value.

If returning a last-modified value causes difficulty (eg with Tomcat 4.0.1) then we return -1.

Overrides:

getLastModified in class javax.servlet.http.HttpServlet

Parameters:

request - The servlet request we are processing

getDataSource

private static DataSourceBean getDataSource(javax.servlet.ServletConfig config,
                                            javax.servlet.http.HttpServletRequest request)

Get singleton (per-servlet-context) data pipeline/cache instance. The config param must not be null, but for some operations (such as calling destroy()) request can be null.

getBundleExhibitName

private static final Name.ExhibitFull getBundleExhibitName(DataSourceBean dsb)

Get full exhibit name of the latest javadoc bundle; null if none.

getZIPEntryOffsets

private static java.util.SortedMap<java.lang.CharSequence,FileTools.ZE> getZIPEntryOffsets(DataSourceBean dsb)

Get ZIP directory/offsets; null if none. The keys of the returned (immutable) map are valid files/entries in the ZIP.

Each value is the (non-negative) offset from the start of the ZIP file to the start of its entry as can be read with ZipInputStream.

This is cached against the AEP instance for efficiency. (We might have to go back across the network to the master to fetch this if we don't have the entire bundle cached locally, for example, which is slow.)

On successfully cacheing this we read the first byte of the archive to try to trigger (pre)cacheing of at least an enclosing early chunk.