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//---IMPORTS--- |
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import java.util.*; |
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import java.io.*; |
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import uk.ac.ukc.iscream.util.*; |
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/** |
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* The component manager is the starting point for all |
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*/ |
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public static final String DEFAULTPROPERTIES = "./etc/default.properties"; |
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|
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/** |
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* The default time to wait before retrying |
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* component. |
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*/ |
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public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5; |
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|
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//---STATIC METHODS--- |
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/** |
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* @param args the command line arguments |
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*/ |
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public static void main(String[] args) { |
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System.out.println("--- I-Scream System Component Manager ---"); |
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System.out.println("--- i-scream Server Component Manager ---"); |
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System.out.println("--- Starting System ---"); |
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|
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// get the command line args |
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// this is a bit messy and should be looked at |
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String defaultProperties = DEFAULTPROPERTIES; |
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String filterName = null; |
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if (args.length > 0) { |
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if (args[0].equals("-l")) { |
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defaultProperties = args[1]; |
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} else if (args[0].equals("-f")) { |
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filterName = args[1]; |
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} else if (args[2].equals("-l")) { |
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filterName = args[3]; |
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} else if (args[2].equals("-f")) { |
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filterName = args[3]; |
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} else { |
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for(int i=0; i < args.length; i++) { |
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if(args[i].equals("-h")) { |
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usage(); |
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} |
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} |
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else if(args[i].equals("-f")) { |
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i++; filterName = args[i]; |
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} |
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else if(args[i].equals("-l")) { |
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i++; defaultProperties = args[i]; |
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} |
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else { |
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usage(); |
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} |
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} |
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|
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// load the default properties file into the system properties |
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// get the list of components |
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String componentList = System.getProperty("uk.ac.ukc.iscream.ComponentList"); |
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StringTokenizer st = new StringTokenizer(componentList, ";"); |
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_componentsToStart = new LinkedList(); |
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// this could be done using reflection |
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// but..well..we don't ;-p |
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while (st.hasMoreTokens()){ |
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String componentName = st.nextToken(); |
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Component component = null; |
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System.out.println(toString + ": starting component - " + componentName); |
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|
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// ### This is where the list of supported components is checked! ### |
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if (componentName.equalsIgnoreCase("core")) { |
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component = new uk.ac.ukc.iscream.core.Core(); |
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// note the passing of the Filter's name in its constructor |
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} else if (componentName.equalsIgnoreCase("filter")) { |
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component = new uk.ac.ukc.iscream.filter.FilterMain(filterName); |
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} else if (componentName.equalsIgnoreCase("client")) { |
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component = new uk.ac.ukc.iscream.client.ClientMain(); |
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} |
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// ### Add new component constructors in the above section! ### |
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// build the list of components to start |
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if (component != null) { |
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try { |
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component.start(); |
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} catch (ComponentStartException e) { |
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System.err.println(toString + ": ERROR starting component - " + componentName); |
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System.err.println(toString + ": component reports - " + e.getMessage()); |
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System.exit(1); |
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} |
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_componentsToStart.add(component); |
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} else { |
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System.err.println(toString + ": WARNING unsupported component not started"); |
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System.err.println(toString + ": WARNING unsupported component not started: "+componentName); |
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} |
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} |
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System.out.println(toString + ": running"); |
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|
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// get the value for timeout |
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|
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String confTimeout = null; |
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try { |
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confTimeout = System.getProperty("uk.ac.ukc.iscream.ComponentTimeout"); |
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confTimeout.trim(); |
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_startTimeout = Integer.parseInt(confTimeout); |
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} catch (NumberFormatException e) { |
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_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT; |
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System.err.println(toString + ": unable to read uk.ac.ukc.iscream.ComponentTimeout value (" + confTimeout + "), using default!"); |
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} |
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System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds"); |
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|
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// startup the system components |
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startUp(); |
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|
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// block on the ORB...in time, management functionality can be placed here. |
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refman.getORB().run(); |
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// if we detect a CORBA communication error, we'll restart all the components. |
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// !! this doesn't appear to work !! |
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while(true) { |
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try { |
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refman.getORB().run(); |
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} catch (org.omg.CORBA.COMM_FAILURE e) { |
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System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage()); |
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System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!"); |
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} |
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startUp(); |
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} |
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} |
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/** |
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* Starts the components as obtained from the configuration. |
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* This method calls the start() methods on all the components. |
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* If a component fails to start due to a CORBA communication |
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* problem, then it catches this and tries to start it again |
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* according to uk.ac.ukc.iscream.ComponentTimeout time. |
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* |
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* If the server dies and CORBA connections are lost, this method |
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* is called again. |
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*/ |
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private static void startUp() { |
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// now we try and start the beast up |
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boolean tryAgain = true; |
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Component component = null; |
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|
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// keep trying until we've started all the components. |
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// maybe add support for a limited number of retries |
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while(tryAgain) { |
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Iterator i = _componentsToStart.iterator(); |
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LinkedList failedComponents = new LinkedList(); |
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// go through all the components |
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while(i.hasNext()) { |
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// get a refence to the component |
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component = (Component) i.next(); |
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System.out.println(toString + ": starting component - " + component.toString()); |
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|
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// check it's dependencies |
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boolean depOK = component.depCheck(); |
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if(depOK) { |
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// it should be ok to start the component |
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try { |
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// start the component |
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component.start(); |
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} catch (ComponentStartException e) { |
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// if we get this then there was a problem |
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// that we can't recover from |
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System.err.println(toString + ": ERROR starting component - " + component.toString()); |
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System.err.println(toString + ": component reports - " + e.getMessage()); |
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System.exit(1); |
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} |
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} |
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else { |
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// it seems the depedencies failed |
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// so we want to try again after a delay |
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System.err.println(toString + ": WARNING Component reported dependency failure"); |
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System.err.println(toString + ": This could be because it can't communicate with components it needs."); |
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|
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// make a list of the failed components |
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failedComponents.add(component); |
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} |
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} |
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|
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// if we had some failed components that we can retry |
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if (failedComponents.size() > 0) { |
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System.err.println(toString + ": WARNING One or more components failed to start correctly."); |
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System.err.println(toString + ": Will try again in " + _startTimeout + " seconds"); |
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|
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// our list is now the failed list |
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_componentsToStart = failedComponents; |
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|
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// sleep for a given timeout |
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try { |
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Thread.sleep(_startTimeout * 1000); |
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} catch (InterruptedException e) { |
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// we're not bothered |
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} |
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// otherwise we started everything |
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} else { |
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// so we set to exit the loop |
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tryAgain = false; |
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} |
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} |
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|
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System.out.println(toString + ": running"); |
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} |
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|
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/** |
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* A simple method to print the usage of this class. |
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* It never returns, but instead exits to the system |
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* with a value 1, to indicate the system did not start |
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//---ATTRIBUTES--- |
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//---STATIC ATTRIBUTES--- |
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|
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private static LinkedList _componentsToStart; |
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private static int _startTimeout = 0; |
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} |