User: mulder
Date: 00/09/12 19:06:02
Added: src/main/org/jboss/dependencies DependencyManager.java
Log:
Add handling of MBean dependencies to startup sequence.
Revision Changes Path
1.1 jboss/src/main/org/jboss/dependencies/DependencyManager.java
Index: DependencyManager.java
===================================================================
package org.jboss.dependencies;
import java.io.IOException;
import java.io.StringReader;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import javax.management.MBeanServer;
import javax.management.ObjectName;
import javax.management.ReflectionException;
import org.xml.sax.AttributeList;
import org.xml.sax.HandlerBase;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import com.sun.xml.parser.Parser;
import com.sun.xml.parser.Resolver;
public class DependencyManager {
private final static boolean DEBUG=false;
private HashMap dependencies;
private HashSet loadedBeans;
private HashMap remainingBeans;
private HashSet pendingBeans;
private MBeanServer server;
public DependencyManager() {
dependencies = new HashMap();
loadedBeans = new HashSet();
remainingBeans = new HashMap();
pendingBeans = new HashSet();
}
public void loadXML(String source) {
dependencies.clear();
Parser parser = new Parser();
try {
parser.setDocumentHandler(new SAXHandler());
InputSource input = new InputSource(new StringReader(source));
parser.parse(input);
} catch(IOException e) {
e.printStackTrace();
} catch(SAXException e) {
e.printStackTrace();
}
}
public void startMBeans(MBeanServer server) {
this.server = server;
loadedBeans.clear();
remainingBeans.clear();
pendingBeans.clear();
Iterator it = server.queryNames(null, null).iterator();
while(it.hasNext()) {
ObjectName name = (ObjectName)it.next();
String service = getService(name);
if(service == null)
continue;
Set set = (Set)remainingBeans.get(service);
if(set == null)
set = new HashSet();
set.add(name);
remainingBeans.put(service, set);
}
it = ((Map)remainingBeans.clone()).keySet().iterator();
while(it.hasNext()) {
String next = (String)it.next();
if(!processMBean(next)) {
System.out.println("Unable to load service '"+next+"'");
}
}
System.out.println(loadedBeans.size()+" services loaded.");
loadedBeans.clear();
dependencies.clear();
}
private boolean processMBean(String target) {
if(pendingBeans.contains(target))
throw new RuntimeException("Circular dependencies!");
if(loadedBeans.contains(target))
return true;
if(DEBUG) System.out.println("Processing service '"+target+"'");
pendingBeans.add(target);
Set set = (Set)dependencies.get(target);
if(set == null) {
return loadMBean(target);
} else {
Iterator it = set.iterator();
while(it.hasNext()) {
Dependency dep = (Dependency)it.next();
if(DEBUG) System.out.println(" Service '"+target+"' depends on
'"+dep.name+"'");
if(!loadedBeans.contains(dep.name)) {
boolean result = processMBean(dep.name);
if(!result && dep.required)
return false;
}
}
return loadMBean(target);
}
}
private boolean loadMBean(String target) {
boolean loaded = false;
Set set = (Set)remainingBeans.get(target);
if(set != null) {
if(DEBUG) System.out.println("Starting service '"+target+"'");
Iterator it = set.iterator();
while(it.hasNext()) {
ObjectName name = (ObjectName)it.next();
if(DEBUG) System.out.println("Starting instance
'"+name.getCanonicalName()+"'");
try {
server.invoke(name, "start", new Object[0], new String[0]);
loaded = true;
} catch(ReflectionException e) {
if(e.getTargetException() instanceof NoSuchMethodException) {
loaded = true; // This bean doesn't have a start!
} else {
System.out.println("Error starting service
'"+name.getCanonicalName()+"': "+e.getTargetException());
loaded = false;
break;
}
} catch(Throwable t) {
System.out.println("Error starting service
'"+name.getCanonicalName()+"': "+t);
loaded = false;
break;
}
}
remainingBeans.remove(target);
dependencies.remove(target);
}
loadedBeans.add(target);
pendingBeans.remove(target);
return loaded;
}
private String getService(ObjectName oName) {
String name = oName.getCanonicalName();
int pos = name.indexOf("service=");
if(pos < 0)
return null;
int test, end = name.length();
test = name.indexOf(',', pos+8);
if(test > -1 && test < end)
end = test;
test = name.indexOf(';', pos+8);
if(test > -1 && test < end)
end = test;
return name.substring(pos+8, end);
}
public void dump() {
Iterator it = dependencies.keySet().iterator();
while(it.hasNext()) {
String key = (String)it.next();
Iterator child = ((HashSet)dependencies.get(key)).iterator();
while(child.hasNext()) {
Dependency dep = (Dependency)child.next();
System.out.println(key+" depends on "+dep.name+(dep.required ? "
REQUIRED" : ""));
}
}
}
public static void main(String args[]) {
StringBuffer total = new StringBuffer();
try{
java.io.BufferedReader reader = new java.io.BufferedReader(new
java.io.FileReader(new java.io.File(args[0])));
String line;
while((line = reader.readLine()) != null)
total.append(line).append('\n');
DependencyManager dm = new DependencyManager();
dm.loadXML(total.toString());
dm.dump();
} catch(IOException e) {e.printStackTrace();}
}
private class SAXHandler extends HandlerBase {
private String currentService;
public void endElement(String name) throws SAXException {
if(name.equals("service"))
currentService = null;
}
public void startElement(String name, AttributeList atts) throws
SAXException {
if(name.equals("service")) {
currentService = atts.getValue("name");
dependencies.put(currentService, new HashSet());
} else if(name.equals("dependency")) {
HashSet set = (HashSet)dependencies.get(currentService);
set.add(new Dependency(atts.getValue("service"),
atts.getValue("required")));
}
}
}
}
class Dependency {
public String name;
public boolean required;
public Dependency(String name, String required) {
this.name = name;
this.required = new Boolean(required).booleanValue();
}
}
