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package com.sun.enterprise.web.ara.rules;
import com.sun.enterprise.web.ara.IsolationRulesExecutor;
import com.sun.enterprise.web.connector.grizzly.Pipeline;
import com.sun.enterprise.web.connector.grizzly.LinkedListPipeline;
import com.sun.enterprise.web.connector.grizzly.Rule;
import com.sun.enterprise.web.connector.grizzly.ReadTask;
import com.sun.enterprise.web.connector.grizzly.SelectorThread;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.StringTokenizer;
import java.util.concurrent.ConcurrentHashMap;
import java.util.logging.Level;
/**
* Based on the application context-root, configure the <code>ReadTask</code>
* <code>Pipeline</code>. Based on the thread-ratio defined in domain.xml, an
* application can have privileged <code>Pipeline</code>, configured to
* use specific percentage of the maximum number of threads. This
* <code>Rule</code> instanciate two types of <code>Pipeline</code>
*
* <code>privilegedPipeline</code> is will be used to execute privileged
* applications.
*
* <code>victimsPipeline</code> is will be used to execute others
* application that aren't included within the privileged tokens.
*
* An application is marked privileged if the set of <code>Rule</code> applied
* to the application requests is matched.
*
* @author Jeanfrancois Arcand
*/
public class ThreadRatioRule implements Rule<ReadTask> {
protected final static String RESERVE = "reserve";
protected final static String CEILING = "ceiling";
protected final static String ALLOCATION_MODE =
"com.sun.enterprise.web.ara.policyMethod";
protected final static String RULE_TOKENS =
"com.sun.enterprise.web.ara.policyMetric";
protected final static String QUERY_STRING="?";
protected final static String PATH_STRING="/";
/**
* The <code>ReadTask</code> attached to this <code>Rule</code>
*/
protected ReadTask readTask;
/**
* The <code>Pipeline</code> configured based on the
* <code>threadRatio</code>. This <code>Pipeline</code> is only used
* by privileged application.
*/
protected final static ConcurrentHashMap<String,Pipeline> pipelines
= new ConcurrentHashMap<String,Pipeline>();
/**
* The list of privileged token used to decide if a request can be
* serviced by the privileged <code>Pipeline</code>.
*/
protected final static ConcurrentHashMap<String,Double>
privilegedTokens = new ConcurrentHashMap<String,Double>();
/**
* The thread ratio used when an application isn't listed as a privileged
* application.
*/
protected static double leftRatio = 1;
/**
* The allocation mode used: celling or Reserve. With Ceiling policy,
* the strategy is to wait until all apps queus are showing some slack.
* With Reserve policiy, if 100% reservation is made by other apps,
* cancel the request processing.
*/
protected static String allocationPolicy = RESERVE;
static {
try{
if ( System.getProperty(RULE_TOKENS) != null){
StringTokenizer privList =
new StringTokenizer(System.getProperty(RULE_TOKENS),",");
StringTokenizer privElement;
String tokens;
double countRatio = 0;
double tokenValue;
while (privList.hasMoreElements()){
privElement = new StringTokenizer(privList.nextToken());
while (privElement.hasMoreElements()){
tokens = privElement.nextToken();
int index = tokens.indexOf("|");
tokenValue = Double.valueOf(tokens.substring(index+1));
privilegedTokens.put
(tokens.substring(0, index),tokenValue);
countRatio += tokenValue;
}
}
if ( countRatio > 1 ) {
SelectorThread.logger().log(Level.WARNING,
"Thread ratio too high. The total must be lower or equal to 1");
} else {
leftRatio = 1 - countRatio;
}
}
} catch (Exception ex){
SelectorThread.logger()
.log(Level.WARNING,"Unable to parse thread ratio", ex);
}
if ( System.getProperty(ALLOCATION_MODE) != null){
allocationPolicy = System.getProperty(ALLOCATION_MODE);
if ( !allocationPolicy.equals(RESERVE) &&
!allocationPolicy.equals(CEILING) ){
SelectorThread.logger()
.log(Level.WARNING,"Invalid allocation policy");
allocationPolicy = RESERVE;
}
}
}
/**
* Creates a new ThreadRationRule.
*/
public ThreadRatioRule() {
}
/**
* Attach a <code>ReadTask</code> to this rule.
*/
public void attach(ReadTask o) {
this.readTask = o;
}
/**
* Return the current attachement.
*/
public ReadTask attachement(){
return readTask;
}
/**
* Invoke the rule. Based on the result of the
* <code>ContextRootAlgorithm</code>, configure the <code>ReadTask</code>
* <code>Pipeline</code>.
*/
public Integer call() throws Exception{
boolean noCache = false;
if ( leftRatio == 0 ) {
if ( allocationPolicy.equals(RESERVE) )
return IsolationRulesExecutor.RULE_BLOCKED;
else if ( allocationPolicy.equals(CEILING) ) {
// If true, then we need to wait for free space. If false, then
// we can go ahead and let the task execute with its default
// pipeline
if ( isPipelineInUse() )
return IsolationRulesExecutor.RULE_DELAY;
else
noCache = true;
}
}
String token = getContextRoot();
// Lazy instanciation
Pipeline pipeline = pipelines.get(token);
if ( pipeline == null ){
pipeline = applyRule(token);
pipelines.put(token,pipeline);
}
readTask.setPipeline(pipeline);
if (!noCache)
return IsolationRulesExecutor.RULE_OK;
else
return IsolationRulesExecutor.RULE_OK_NOCACHE;
}
// ------------------------------------------------ Pipeline ------------//
/***
* Get the context-root from the <code>ByteBuffer</code>
*/
protected String getContextRoot(){
// (1) Get the token the Algorithm has processed for us.
ByteBuffer byteBuffer = readTask.getByteBuffer();
byte[] chars = new byte[byteBuffer.limit() - byteBuffer.position()];
byteBuffer.get(chars);
String token = new String(chars);
int index = token.indexOf(PATH_STRING);
if ( index != -1){
token = token.substring(0,index);
}
// Remove query string.
index = token.indexOf(QUERY_STRING);
if ( index != -1){
token = token.substring(0,index);
}
boolean slash = token.endsWith(PATH_STRING);
if ( slash ){
token = token.substring(0,token.length() -1);
}
return token;
}
/**
* Apply the thread ratio.
*/
protected Pipeline applyRule(String token){
Pipeline p = readTask.getPipeline();
int maxThreads = p.getMaxThreads();
Double threadRatio = privilegedTokens.get(token);
if (threadRatio == null) {
threadRatio = (leftRatio == 0? 0.5:leftRatio);
}
int privilegedCount = (threadRatio==1 ? maxThreads :
(int) (maxThreads * threadRatio) + 1);
return newPipeline(privilegedCount,p);
}
/**
* Creates a new <code>Pipeline</code>
*/
protected Pipeline newPipeline(int threadCount,Pipeline p){
// Run the Task on the SelectorThread
if ( threadCount == 0){
return null;
}
Pipeline pipeline = new LinkedListPipeline();
pipeline.setMinThreads(1);
pipeline.setMaxThreads(threadCount);
pipeline.setName(p.getName());
pipeline.setQueueSizeInBytes(
readTask.getSelectorThread().getQueueSizeInBytes());
pipeline.initPipeline();
pipeline.startPipeline();
return pipeline;
}
/**
* Check to see if the privileged pipeline are in-use right now.
*/
protected boolean isPipelineInUse(){
Collection<Pipeline> collection = pipelines.values();
for (Pipeline pipeline: collection){
if (pipeline.size() > 0) {
return true;
}
}
return false;
}
// ---------------------------------------------------------------------//
/**
* Cancel execution of this rule.
*/
public void cancel() {
readTask = null;
}
/**
* Return the time in second before this rule will be executed.
*/
public int getExecutionTime() {
return -1; // now
}
/**
* Set the interval in seconds to wait before executing this rule.
*/
public void setExecutionTime(int time) {
;
}
/**
* Set the <code>Future</code> associated with this execution of this rule.
*/
public void setFuture(java.util.concurrent.Future future) {
;
}
}
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