Author: mck
Date: Sat Oct 29 12:06:47 2011
New Revision: 1194877
URL: http://svn.apache.org/viewvc?rev=1194877&view=rev
Log:
TILES-539 - OptionsRenderer
Added:
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java
(with props)
Added:
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java
URL:
http://svn.apache.org/viewvc/tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java?rev=1194877&view=auto
==============================================================================
---
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java
(added)
+++
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java
Sat Oct 29 12:06:47 2011
@@ -0,0 +1,141 @@
+package org.apache.tiles.extras.renderer;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.tiles.Attribute;
+import org.apache.tiles.ListAttribute;
+import org.apache.tiles.access.TilesAccess;
+import org.apache.tiles.request.ApplicationContext;
+import org.apache.tiles.request.Request;
+import org.apache.tiles.request.render.TypeDetectingRenderer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Provides a custom "options" syntax for attributes.
+ * The first option that can be rendered is.
+ * Comes from http://tech.finn.no/the-ultimate-view/<p/>
+ *
+ * Actual rendering is delegated to the TypeDetectingRenderer that's supplied
in the constructor.
+ *
+ * For example:
+ * "/WEB-INF/tiles/fragments/${options[myoptions]}/content.jsp"
+ * given the myptions list-attribute is defined like:
+ * <pre>
+ <put-list-attribute name="myoptions">
+ <add-list-attribute>
+ <add-attribute value="car"/>
+ <add-attribute value="vechile"/>
+ <add-attribute value="advert"/>
+ </add-list-attribute>
+ </put-list-attribute>
+ </pre>
+ * will look for content.jsp
+ * first in "/WEB-INF/tiles/fragments/car/" then
+ * second in "/WEB-INF/tiles/fragments/vechile/" and
+ * last in "/WEB-INF/tiles/fragments/advert".
+ * <p/>
+ * <p/>
+ * Currently only supports one occurrance of such an "option" pattern in the
attribute's value.
+ *
+ */
+public final class OptionsRenderer implements TypeDetectingRenderer {
+
+ private static final Pattern OPTIONS_PATTERN
+ = Pattern.compile(Pattern.quote("${options[") + ".+" +
Pattern.quote("]}"));
+
+ private static final Logger LOG =
LoggerFactory.getLogger(OptionsRenderer.class);
+
+ private final ApplicationContext applicationContext;
+ private final TypeDetectingRenderer renderer;
+
+ public OptionsRenderer(final ApplicationContext applicationContext, final
TypeDetectingRenderer renderer){
+ this.applicationContext = applicationContext;
+ this.renderer = renderer;
+ }
+
+ @Override
+ public boolean isRenderable(final String path, final Request request) {
+ return renderer.isRenderable(path, request);
+ }
+
+ @Override
+ public void render(final String path, final Request request) throws
IOException {
+
+ final Matcher matcher = OPTIONS_PATTERN.matcher((String) path);
+
+ if (null != matcher && matcher.find()) {
+ boolean done = false;
+ final String match = matcher.group();
+ ListAttribute fallbacks = (ListAttribute) TilesAccess
+ .getCurrentContainer(request)
+ .getAttributeContext(request)
+ .getLocalAttribute(match);
+
+ for (Attribute option : (List<Attribute>) fallbacks.getValue()) {
+ final String template =
path.replaceFirst(Pattern.quote(match), (String)option.getValue());
+ if(!Cache.isTemplateMissing(template)){
+ try {
+ if (null != applicationContext.getResource(template))
{ // can throw FileNotFoundException !
+ renderer.render(template, request); // can throw
FileNotFoundException !
+ done = true;
+ Cache.setIfAbsentTemplateFound(template, true);
+ }
+ } catch (FileNotFoundException ex) {
+ if(ex.getMessage().contains(template)){
+ // expected outcome. continue loop.
+ LOG.trace(ex.getMessage());
+ }else{
+ // comes from an inner
templateAttribute.render(..) so throw on
+ throw ex;
+ }
+ } catch(IOException ex){ //xxx ???
+ throw ex;
+ }
+ Cache.setIfAbsentTemplateFound(template, false);
+ }
+ if(done){ break; }
+ }
+ if (!done) {
+ throw new IOException("None of the fallback options existed for
" + path);
+ }
+ } else {
+ renderer.render(path, request);
+ }
+ }
+
+ private static final class Cache{
+
+ /** It takes CACHE_LIFE milliseconds for any hot deployments to
register.
+ */
+ private static final ConcurrentMap<String,Boolean> TEMPLATE_EXISTS
+ = new ConcurrentHashMap<String,Boolean>();
+
+ private volatile static long cacheLastCleaned =
System.currentTimeMillis();
+ private static final long CACHE_LIFE = 1000 * 60 * 5;
+
+ static boolean isTemplateMissing(final String template){
+ if(System.currentTimeMillis() > cacheLastCleaned + CACHE_LIFE){
+ cacheLastCleaned = System.currentTimeMillis();
+ TEMPLATE_EXISTS.clear();
+ return false;
+ }else{
+ return TEMPLATE_EXISTS.containsKey(template) &&
!TEMPLATE_EXISTS.get(template);
+ }
+ }
+
+ static void setIfAbsentTemplateFound(final String template, final
boolean found){
+ if(!TEMPLATE_EXISTS.containsKey(template)){
+ TEMPLATE_EXISTS.putIfAbsent(template, found);
+ }
+ }
+
+ private Cache(){}
+ }
+}
Propchange:
tiles/framework/trunk/tiles-parent/tiles-extras/src/main/java/org/apache/tiles/extras/renderer/OptionsRenderer.java
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svn:keywords = Id
