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Added ability to retrieve last modified time of the site-specific jar

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git-svn-id: https://samskivert.googlecode.com/svn/trunk@427 6335cc39-0255-0410-8fd6-9bcaacd3b74c
This commit is contained in:
mdb
2001-11-06 04:48:54 +00:00
parent d9622d84de
commit 4d10799b9e
1 changed files with 117 additions and 42 deletions
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projects/samskivert/src/java/com/samskivert/servlet/SiteResourceLoader.java
+117 -42
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@@ -1,5 +1,5 @@
//
// $Id: SiteResourceLoader.java,v 1.2 2001/11/05 18:08:01 mdb Exp $
// $Id: SiteResourceLoader.java,v 1.3 2001/11/06 04:48:54 mdb Exp $
//
// samskivert library - useful routines for java programs
// Copyright (C) 2001 Michael Bayne
@@ -133,6 +133,33 @@ public class SiteResourceLoader
*/
public InputStream getResourceAsStream (int siteId, String path)
throws IOException
{
return getResourceAsStream(siteId, path, true);
}
/**
* Loads the specific resource, from the site-specific jar file if one
* exists and contains the specified resource, or via the servlet
* context (if <code>fallbackToServletContext</code> is true). If no
* resource exists with that path in either location, null will be
* returned.
*
* @param siteId the unique identifer for the site for which we are
* loading the resource.
* @param path the path to the desired resource.
* @param fallbackToServletContext if true, the servlet context will
* be searched for the resource if there is no site-specific
* resource. If false, it will not.
*
* @return an input stream via which the resource can be read or null
* if no resource could be located with the specified path.
*
* @exception IOException thrown if an I/O error occurs while loading
* a resource.
*/
public InputStream getResourceAsStream (int siteId, String path,
boolean fallbackToServletContext)
throws IOException
{
InputStream stream = null;
@@ -146,7 +173,7 @@ public class SiteResourceLoader
// if we didn't find a site-specific resource (or didn't look for
// one because we're loading for the default site), we need to
// attempt to load the resource from the servlet context
if (stream == null) {
if (stream == null && fallbackToServletContext) {
stream = _context.getResourceAsStream(path);
}
@@ -154,6 +181,23 @@ public class SiteResourceLoader
return stream;
}
/**
* Returns the last modification time of the site-specific jar file
* for the specified site.
*
* @exception IOException thrown if an error occurs accessing the
* site-specific jar file (like it doesn't exist).
*/
public long getLastModified (int siteId)
throws IOException
{
// synchronize on the lock to ensure that only one thread per site
// is concurrently executing
synchronized (getLock(siteId)) {
return getBundle(siteId).getLastModified();
}
}
/**
* Fetches the resource with the specified path from the site-specific
* jar file associated with the specified site.
@@ -161,43 +205,13 @@ public class SiteResourceLoader
protected InputStream getSiteResourceAsStream (int siteId, String path)
throws IOException
{
Object lock = null;
// Log.info("Loading site resource [siteId=" + siteId +
// ", path=" + path + "].");
// we synchronize on a per-site basis, but we use a separate lock
// object for each site so that the process of loading a bundle
// for the first time does not require blocking access to
// resources from other sites
synchronized (_locks) {
lock = _locks.get(siteId);
// create a lock object if we haven't one already
if (lock == null) {
_locks.put(siteId, lock = new Object());
}
}
// now synchronize on the lock to ensure that only one thread per
// site is concurrently executing
synchronized (lock) {
// look up the site resource bundle for this site
SiteResourceBundle bundle = (SiteResourceBundle)
_bundles.get(siteId);
// if we haven't got one, create one
if (bundle == null) {
// obtain the string identifier for this site
String ident = _siteIdent.getSiteString(siteId);
// compose that with the jar file directory to obtain the
// path to the site-specific jar file
File file = new File(_jarPath, ident + JAR_EXTENSION);
// create a handle for this site-specific jar file
bundle = new SiteResourceBundle(file);
// cache our new bundle
_bundles.put(siteId, bundle);
}
// synchronize on the lock to ensure that only one thread per site
// is concurrently executing
synchronized (getLock(siteId)) {
SiteResourceBundle bundle = getBundle(siteId);
// make sure the path has no leading slash
if (path.startsWith("/")) {
@@ -209,6 +223,55 @@ public class SiteResourceLoader
}
}
/**
* We synchronize on a per-site basis, but we use a separate lock
* object for each site so that the process of loading a bundle for
* the first time does not require blocking access to resources from
* other sites.
*/
protected Object getLock (int siteId)
{
Object lock = null;
synchronized (_locks) {
lock = _locks.get(siteId);
// create a lock object if we haven't one already
if (lock == null) {
_locks.put(siteId, lock = new Object());
}
}
return lock;
}
/**
* Obtains the site-specific jar file for the specified site. This
* should only be called when the lock for this site is held.
*/
protected SiteResourceBundle getBundle (int siteId)
throws IOException
{
// look up the site resource bundle for this site
SiteResourceBundle bundle = (SiteResourceBundle)
_bundles.get(siteId);
// if we haven't got one, create one
if (bundle == null) {
// obtain the string identifier for this site
String ident = _siteIdent.getSiteString(siteId);
// compose that with the jar file directory to obtain the
// path to the site-specific jar file
File file = new File(_jarPath, ident + JAR_EXTENSION);
// create a handle for this site-specific jar file
bundle = new SiteResourceBundle(file);
// cache our new bundle
_bundles.put(siteId, bundle);
}
return bundle;
}
/**
* Encapsulates the information we need to load data from a site
* resource bundle as well as to determine whether the loaded bundle
@@ -223,10 +286,6 @@ public class SiteResourceLoader
/** A handle on the site-specific jar file. */
public File file;
/** The last modified time of the jar file at the time that we
* opened it for reading. */
public long lastModified;
/**
* Constructs a new site resource bundle. The associated jar file
* will be opened the first time a resource is read.
@@ -256,6 +315,18 @@ public class SiteResourceLoader
return entry == null ? null : jarFile.getInputStream(entry);
}
/**
* Returns the last modified time of the underlying jar file.
*/
public long getLastModified ()
throws IOException
{
// open or reopen our underlying jar file as necessary
refreshJarFile();
return _lastModified;
}
/**
* Reopens our site-specific jar file if it has been modified
* since it was last opened.
@@ -265,9 +336,9 @@ public class SiteResourceLoader
{
// determine whether or not we need to create a new jarfile
// instance
if (file.lastModified() > lastModified) {
if (file.lastModified() > _lastModified) {
// make a note of the last modified time
lastModified = file.lastModified();
_lastModified = file.lastModified();
// close our old jar file if we've got one
if (jarFile != null) {
@@ -281,6 +352,10 @@ public class SiteResourceLoader
jarFile = new JarFile(file);
}
}
/** The last modified time of the jar file at the time that we
* opened it for reading. */
protected long _lastModified;
}
/** The site identifier we use to identify requests. */