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Merge branch 'maint-rel-1.6' into develop

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j2blake 2013-11-25 11:49:51 -05:00
commit 45c2d8e5e3
1 changed files with 36 additions and 11 deletions
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47
webapp/src/edu/cornell/mannlib/vitro/webapp/freemarker/config/FreemarkerConfigurationImpl.java
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@ -3,6 +3,7 @@
package edu.cornell.mannlib.vitro.webapp.freemarker.config;
import java.io.IOException;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
@ -35,28 +36,52 @@ import freemarker.template.utility.DeepUnwrap;
* Extend the Freemarker Configuration class to include some information that is
* particular to the current request.
*
* Takes advantage of the fact that each servlet request runs in a separate
* thread. Stores the request-based information in a ThreadLocal. Override any
* methods that should return that information instead of (or in addition to)
* the common info.
* A reference to the current request is not always available to the Freemarker
* Configuration, so we take advantage of the fact that each request runs in a
* separate thread, and store a reference to that request in a ThreadLocal
* object.
*
* Then, we override any methods that should return that request-based
* information instead of (or in addition to) the common info.
*
* Only the getters are overridden, not the setters. So if you call
* setAllSharedVariables(), for example, it will have no effect on the
* request-based information.
*
* Notice that the reference to the current request is actually stored through a
* WeakReference. This is because the ThreadLocal will not be cleared when the
* webapp is stopped, so none of the references from that ThreadLocal are
* eligible for garbage collection. If any of those references is an instance of
* a class that is loaded by the webapp, then the webapp ClassLoader is not
* eligible for garbage collection. This would be a huge memory leak.
*
* Thanks to the WeakReference, the request is eligible for garbage collection
* if nothing else refers to it. In theory, this means that the WeakReference
* could return a null, but if the garbage collector has taken the request, then
* who is invoking this object?
*/
public class FreemarkerConfigurationImpl extends Configuration {
private static final Log log = LogFactory
.getLog(FreemarkerConfigurationImpl.class);
private final ThreadLocal<RequestBasedInformation> rbiRef = new ThreadLocal<>();
private static final String ATTRIBUTE_NAME = RequestBasedInformation.class
.getName();
private final ThreadLocal<WeakReference<HttpServletRequest>> reqRef = new ThreadLocal<>();
void setRequestInfo(HttpServletRequest req) {
rbiRef.set(new RequestBasedInformation(req, this));
reqRef.set(new WeakReference<>(req));
req.setAttribute(ATTRIBUTE_NAME, new RequestBasedInformation(req, this));
}
private RequestBasedInformation getRequestInfo() {
HttpServletRequest req = reqRef.get().get();
return (RequestBasedInformation) req.getAttribute(ATTRIBUTE_NAME);
}
@Override
public Object getCustomAttribute(String name) {
Map<String, Object> attribs = rbiRef.get().getCustomAttributes();
Map<String, Object> attribs = getRequestInfo().getCustomAttributes();
if (attribs.containsKey(name)) {
return attribs.get(name);
} else {
@ -66,13 +91,13 @@ public class FreemarkerConfigurationImpl extends Configuration {
@Override
public String[] getCustomAttributeNames() {
Set<String> rbiNames = rbiRef.get().getCustomAttributes().keySet();
Set<String> rbiNames = getRequestInfo().getCustomAttributes().keySet();
return joinNames(rbiNames, super.getCustomAttributeNames());
}
@Override
public TemplateModel getSharedVariable(String name) {
Map<String, TemplateModel> vars = rbiRef.get().getSharedVariables();
Map<String, TemplateModel> vars = getRequestInfo().getSharedVariables();
if (vars.containsKey(name)) {
return vars.get(name);
} else {
@ -82,7 +107,7 @@ public class FreemarkerConfigurationImpl extends Configuration {
@Override
public Set<String> getSharedVariableNames() {
Set<String> rbiNames = rbiRef.get().getSharedVariables().keySet();
Set<String> rbiNames = getRequestInfo().getSharedVariables().keySet();
@SuppressWarnings("unchecked")
Set<String> superNames = super.getSharedVariableNames();
@ -94,7 +119,7 @@ public class FreemarkerConfigurationImpl extends Configuration {
@Override
public Locale getLocale() {
return rbiRef.get().getReq().getLocale();
return getRequestInfo().getReq().getLocale();
}
private String[] joinNames(Set<String> nameSet, String[] nameArray) {