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package com.sun.enterprise.web.ara;
import com.sun.enterprise.web.connector.grizzly.HtmlHelper;
import com.sun.enterprise.web.connector.grizzly.ReadTask;
import com.sun.enterprise.web.connector.grizzly.Rule;
import com.sun.enterprise.web.connector.grizzly.SelectorThread;
import java.util.ArrayList;
import java.util.StringTokenizer;
import java.util.logging.Level;
import com.sun.enterprise.web.ara.rules.PathRule;
/**
* This class execute sequentialy <code>Rule</code>s on a <code>Task</code>
*
* @author Jeanfrancois Arcand
*/
public class IsolationRulesExecutor implements RulesExecutor<IsolatedTask> {
public final static int RULE_OK = 0;
public final static int RULE_DELAY = 1;
public final static int RULE_BLOCKED = 2;
public final static int RULE_OK_NOCACHE = 3;
public final static int RULE_CONTINUE = 4;
private final static String RULE_CLASS =
"com.sun.enterprise.web.ara.rules";
private final static String DELAY_VALUE =
"com.sun.enterprise.web.ara.delay";
/**
* Initial number of <code>Rule</code> to cache.
*/
private final static int INITIAL_RULE_COUNT = 5;
/**
* The list of <code>Rule</code> to apply to a <code>Task</code>
*/
protected ArrayList<Rule> rules = new ArrayList<Rule>();
/**
* The current number of thread used.
*/
private static int currentThreadCount;
/**
* The time this thread will sleep when a rule is delayed.
*/
private static long delayValue = 5 * 1000;
/**
* Is caching allowed
*/
private boolean isCachingAllowed = true;
// ---------------------------------------------------------------------//
public IsolationRulesExecutor() {
loadRules();
if ( System.getProperty(DELAY_VALUE) != null){
delayValue = Long.valueOf(System.getProperty(DELAY_VALUE));
}
}
/**
* Load the list of <code>Rules</code> to apply to a <code>Task</code>
*/
protected void loadRules(){
if ( System.getProperty(RULE_CLASS) != null){
StringTokenizer st = new StringTokenizer(
System.getProperty(RULE_CLASS),",");
while (st.hasMoreTokens()){
rules.add(loadInstance(st.nextToken()));
}
}
if ( rules.size() == 0){
rules.add(new PathRule());
}
}
/**
* Execute the <code>Rule</code>s on the <code>IsolatedTask</code>
* @param isolatedTask the task used.
* @return true if the request processing can continue.
*/
public boolean execute(IsolatedTask isolatedTask) {
ReadTask task = (ReadTask)isolatedTask.getWrappedTask();
Integer status = 0;
int i = 0;
isCachingAllowed = true;
while(true) {
rules.get(i).attach(task);
try{
status = (Integer)rules.get(i).call();
} catch(Exception ex) {
SelectorThread.logger().log(Level.SEVERE,"Rule exception",ex);
return true;
}
isCachingAllowed = (status == RULE_OK_NOCACHE ? false:true);
if (status == RULE_DELAY){
// Wait until the delay expire. The current thread will
// wait and then re-execute the rules.
try{
Thread.sleep(delayValue);
} catch (InterruptedException ex) {
SelectorThread.logger().
log(Level.SEVERE,"Rule delay exception",ex);
}
i = 0;
continue;
} else if ( status == RULE_BLOCKED ){
task.cancelTask("No resources available.", HtmlHelper.OK);
return true;
}
i++;
if (i == rules.size()){
break;
}
}
return (status == RULE_OK || status == RULE_OK_NOCACHE);
}
/**
* Is caching of <code>Rule</code> results allowed
*/
public boolean isCachingAllowed(){
return isCachingAllowed;
}
// -------------------------------------------------------- Util --------//
/**
* Instanciate a class based on a property.
*/
private Rule loadInstance(String property){
Class className = null;
try{
className = Class.forName(property);
return (Rule)className.newInstance();
} catch (ClassNotFoundException ex){
} catch (InstantiationException ex){
} catch (IllegalAccessException ex){
}
return new PathRule();
}
}
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