server/componentmanager/ComponentManager.java

//---PACKAGE DECLARATION---
package uk.ac.ukc.iscream.componentmanager;

//---IMPORTS---
import java.util.*;
import java.io.*;
import uk.ac.ukc.iscream.util.*;

/**
 * The component manager is the starting point for all
 * server side components of the iscream system.
 * It loads its initial system configuration from the
 * default properties file, it then starts all the iscream
 * components as specified in the default.properties under
 * uk.ac.ukc.iscream.ComponentList
 *
 * @author  $Author: ajm4 $
 * @version $Id: ComponentManager.java,v 1.31 2001/03/01 16:36:52 ajm4 Exp $
 */
public class ComponentManager {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.31 $";
    
    /**
     * The toString() of this class
     * As it won't be instatiated, this is needed.
     * Not also that we pass a null as the class name (as we are static)
     */
    public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
    
    /**
     * The default location of the properties file for the system
     */
    public static final String DEFAULTPROPERTIES = "./etc/default.properties";
    
    /**
     * The default time to wait before retrying 
     * component.
     */
    public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
    
//---STATIC METHODS---

    /**
     * The main method which starts the components as
     * listed in the default.properties file.
     *
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        System.out.println("--- i-scream Server Component Manager ---");
        System.out.println("---          Starting System          ---");        
        
        // get the command line args
        String defaultProperties = DEFAULTPROPERTIES;
        String filterName = null;
        for(int i=0; i < args.length; i++) {
            if(args[i].equals("-h")) {
                usage();
            }
            else if(args[i].equals("-f")) {
                i++; filterName = args[i];
            }
            else if(args[i].equals("-l")) {
                i++; defaultProperties = args[i];
            }
            else {
                usage();
            }
        }

        // load the default properties file into the system properties
        System.out.println(toString + ": initialising - using " + defaultProperties);
        try {
            Properties initProperties = new Properties(System.getProperties());
            initProperties.load(new FileInputStream(new File(defaultProperties)));
            System.setProperties(initProperties);
        } catch (Exception e) {
            System.err.println(toString + ": ERROR " + e.getMessage());
            usage();
        }

        // continue to bring the system up
        System.out.println(toString + ": coming up");
        
        // start the ORB by initialising the ReferenceManager
        ReferenceManager refman = ReferenceManager.getInstance();
        
        // now the ORB is running, we need to activate our RootPOA
        // so that we can start serving requests once servants start up
        refman.activatePOA();
        
        // get the list of components
        String componentList = System.getProperty("uk.ac.ukc.iscream.ComponentList");
        StringTokenizer st = new StringTokenizer(componentList, ";");
        _componentsToStart = new ArrayList();
        
        // this could be done using reflection
        // but..well..we don't ;-p
        while (st.hasMoreTokens()){
            String componentName = st.nextToken();
            Component component = null;
            
            
            // ### This is where the list of supported components is checked! ###
            if (componentName.equalsIgnoreCase("core")) {
                component = new uk.ac.ukc.iscream.core.Core();
            } else if (componentName.equalsIgnoreCase("filtermanager")) {
                component = new uk.ac.ukc.iscream.filtermanager.FilterManager();
            } else if (componentName.equalsIgnoreCase("rootfilter")) {
                component = new uk.ac.ukc.iscream.rootfilter.RootFilter();
            } else if (componentName.equalsIgnoreCase("dbinterface")) {
                component = new uk.ac.ukc.iscream.dbinterface.DBInterface();
            } else if (componentName.equalsIgnoreCase("clientinterface")) {
                component = new uk.ac.ukc.iscream.clientinterface.ClientInterfaceMain();
            // note the passing of the Filter's name in its constructor
            } else if (componentName.equalsIgnoreCase("filter")) {
                component = new uk.ac.ukc.iscream.filter.FilterMain(filterName);
            } else if (componentName.equalsIgnoreCase("client")) {
                component = new uk.ac.ukc.iscream.client.ClientMain();
            }
            // ###  Add new component constructors in the above section! ###
            
            // build the list of components to start
            if (component != null) {
                _componentsToStart.add(component);    
            } else {
                System.err.println(toString + ": WARNING unsupported component not started");
            }
        }
        
        

        // get the value for timeout
        
        String confTimeout = null;
        try {
            confTimeout = System.getProperty("uk.ac.ukc.iscream.ComponentTimeout");
            confTimeout.trim();
            _startTimeout = Integer.parseInt(confTimeout);
        } catch (NumberFormatException e) {
            _startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
            System.err.println(toString + ": unable to read uk.ac.ukc.iscream.ComponentTimeout value (" + confTimeout + "), using default!");
        }
        System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
        
        // startup the system components
        startUp();

            // block on the ORB...in time, management functionality can be placed here.
            // if we detect a CORBA communication error, we'll restart all the components.
            while(true) {
            try {
                refman.getORB().run();
            } catch (org.omg.CORBA.COMM_FAILURE e) {
                System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
                System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
            }
            startUp();
        }
    }

    /**
     * Starts the components as obtained from the configuration.
     * This method calls the start() methods on all the components.
     * If a component fails to start due to a CORBA communication
     * problem, then it catches this and tries to start it again
     * according to uk.ac.ukc.iscream.ComponentTimeout time.
     *
     * If the server dies and CORBA connections are lost, this method
     * is called again.
     */
    private static void startUp() {
        // now we try and start the beast up        
        boolean tryAgain = true;
        Component component = null;
        
        // keep trying until we've started all the components.
        // maybe add support for a limited number of retries
        while(tryAgain) {
            Iterator i = _componentsToStart.iterator();
            ArrayList failedComponents = new ArrayList();
            // go through all the components
            while(i.hasNext()) {
                try {
                    component = (Component) i.next();
                    System.out.println(toString + ": starting component - " + component.toString());
                    
                    // start the component
                    component.start();
                    
                // if we get this then there was a problem
                // that we can't recover from
                } catch (ComponentStartException e) {
                    System.err.println(toString + ": ERROR starting component - " + component.toString());
                    System.err.println(toString + ": component reports - " + e.getMessage());
                    System.exit(1);

                // if we get this exception then we've tried
                // to talk to something which may not be up yet
                // so we want to try again in a minute                
                } catch(ComponentCORBAException e2) {
                    System.err.println(toString + ": WARNING Component reported CORBA communications failure");
                    System.err.println(toString + ": This could be because it can't communicate with components it needs.");
                    System.err.println(toString + ": component reports - " + e2.getMessage());
                    
                    // make a list of the failed components
                    failedComponents.add(component);
                }
            }
            
            // if we had some failed components that we can retry
            if (failedComponents.size() > 0) {
                System.err.println(toString + ": WARNING One or more components failed to start correctly.");
                System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
            
                // our list is now the failed list
                _componentsToStart = failedComponents;
                
                // sleep for a given timeout
                try {    
                    Thread.sleep(_startTimeout * 1000);
                } catch (InterruptedException e) {
                    // we're not bothered
                }
            // otherwise we started everything
            } else {
                // so we set to exit the loop
                tryAgain = false;
            }
        }
                
            System.out.println(toString + ": running");
        }

    /**
     * A simple method to print the usage of this class.
     * It never returns, but instead exits to the system
     * with a value 1, to indicate the system did not start
     * properly.
     */
    public static void usage() {
        System.out.println("USAGE: java uk.ac.ukc.iscream.componentmanager.ComponentManager <option>");
        System.out.println("   or: java -jar iscream.jar <option>");
        System.out.println("WHERE <option>:");
        System.out.println("      -l <filename> - the location of initial system properties");
        System.out.println("                      the default is ./etc/default.properties");
        System.out.println("      -f <name>     - the name of the filter (if there is one configured");
        System.out.println("      -h            - this help screen");
        System.exit(1);
    }

//---CONSTRUCTORS---

//---PUBLIC METHODS---

//---PRIVATE METHODS---

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---
    
//---STATIC ATTRIBUTES---

    private static ArrayList _componentsToStart;
    private static int _startTimeout = 0;

}
Revision:	1.32
Committed:	Thu Mar 1 16:49:49 2001 UTC (23 years, 3 months ago) by ajm
Branch:	MAIN
Changes since 1.31:	+22 -17 lines
Log Message:	Fixed problems with needing attributes to pass components to the startUp() method.
#	Content
1	//---PACKAGE DECLARATION---
2	package uk.ac.ukc.iscream.componentmanager;
3
4	//---IMPORTS---
5	import java.util.*;
6	import java.io.*;
7	import uk.ac.ukc.iscream.util.*;
8
9	/**
10	* The component manager is the starting point for all
11	* server side components of the iscream system.
12	* It loads its initial system configuration from the
13	* default properties file, it then starts all the iscream
14	* components as specified in the default.properties under
15	* uk.ac.ukc.iscream.ComponentList
16	*
17	* @author $Author: ajm4 $
18	* @version $Id: ComponentManager.java,v 1.31 2001/03/01 16:36:52 ajm4 Exp $
19	*/
20	public class ComponentManager {
21
22	//---FINAL ATTRIBUTES---
23
24	/**
25	* The current CVS revision of this class
26	*/
27	public static final String REVISION = "$Revision: 1.31 $";
28
29	/**
30	* The toString() of this class
31	* As it won't be instatiated, this is needed.
32	* Not also that we pass a null as the class name (as we are static)
33	*/
34	public static final String toString = FormatName.getName("ComponentManager", null, REVISION);
35
36	/**
37	* The default location of the properties file for the system
38	*/
39	public static final String DEFAULTPROPERTIES = "./etc/default.properties";
40
41	/**
42	* The default time to wait before retrying
43	* component.
44	*/
45	public static final int DEFAULT_COMPONENT_START_TIMEOUT = 5;
46
47	//---STATIC METHODS---
48
49	/**
50	* The main method which starts the components as
51	* listed in the default.properties file.
52	*
53	* @param args the command line arguments
54	*/
55	public static void main(String[] args) {
56	System.out.println("--- i-scream Server Component Manager ---");
57	System.out.println("--- Starting System ---");
58
59	// get the command line args
60	String defaultProperties = DEFAULTPROPERTIES;
61	String filterName = null;
62	for(int i=0; i < args.length; i++) {
63	if(args[i].equals("-h")) {
64	usage();
65	}
66	else if(args[i].equals("-f")) {
67	i++; filterName = args[i];
68	}
69	else if(args[i].equals("-l")) {
70	i++; defaultProperties = args[i];
71	}
72	else {
73	usage();
74	}
75	}
76
77	// load the default properties file into the system properties
78	System.out.println(toString + ": initialising - using " + defaultProperties);
79	try {
80	Properties initProperties = new Properties(System.getProperties());
81	initProperties.load(new FileInputStream(new File(defaultProperties)));
82	System.setProperties(initProperties);
83	} catch (Exception e) {
84	System.err.println(toString + ": ERROR " + e.getMessage());
85	usage();
86	}
87
88	// continue to bring the system up
89	System.out.println(toString + ": coming up");
90
91	// start the ORB by initialising the ReferenceManager
92	ReferenceManager refman = ReferenceManager.getInstance();
93
94	// now the ORB is running, we need to activate our RootPOA
95	// so that we can start serving requests once servants start up
96	refman.activatePOA();
97
98	// get the list of components
99	String componentList = System.getProperty("uk.ac.ukc.iscream.ComponentList");
100	StringTokenizer st = new StringTokenizer(componentList, ";");
101	_componentsToStart = new ArrayList();
102
103	// this could be done using reflection
104	// but..well..we don't ;-p
105	while (st.hasMoreTokens()){
106	String componentName = st.nextToken();
107	Component component = null;
108
109
110	// ### This is where the list of supported components is checked! ###
111	if (componentName.equalsIgnoreCase("core")) {
112	component = new uk.ac.ukc.iscream.core.Core();
113	} else if (componentName.equalsIgnoreCase("filtermanager")) {
114	component = new uk.ac.ukc.iscream.filtermanager.FilterManager();
115	} else if (componentName.equalsIgnoreCase("rootfilter")) {
116	component = new uk.ac.ukc.iscream.rootfilter.RootFilter();
117	} else if (componentName.equalsIgnoreCase("dbinterface")) {
118	component = new uk.ac.ukc.iscream.dbinterface.DBInterface();
119	} else if (componentName.equalsIgnoreCase("clientinterface")) {
120	component = new uk.ac.ukc.iscream.clientinterface.ClientInterfaceMain();
121	// note the passing of the Filter's name in its constructor
122	} else if (componentName.equalsIgnoreCase("filter")) {
123	component = new uk.ac.ukc.iscream.filter.FilterMain(filterName);
124	} else if (componentName.equalsIgnoreCase("client")) {
125	component = new uk.ac.ukc.iscream.client.ClientMain();
126	}
127	// ### Add new component constructors in the above section! ###
128
129	// build the list of components to start
130	if (component != null) {
131	_componentsToStart.add(component);
132	} else {
133	System.err.println(toString + ": WARNING unsupported component not started");
134	}
135	}
136
137
138
139	// get the value for timeout
140
141	String confTimeout = null;
142	try {
143	confTimeout = System.getProperty("uk.ac.ukc.iscream.ComponentTimeout");
144	confTimeout.trim();
145	_startTimeout = Integer.parseInt(confTimeout);
146	} catch (NumberFormatException e) {
147	_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
148	System.err.println(toString + ": unable to read uk.ac.ukc.iscream.ComponentTimeout value (" + confTimeout + "), using default!");
149	}
150	System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
151
152	// startup the system components
153	startUp();
154
155	// block on the ORB...in time, management functionality can be placed here.
156	// if we detect a CORBA communication error, we'll restart all the components.
157	while(true) {
158	try {
159	refman.getORB().run();
160	} catch (org.omg.CORBA.COMM_FAILURE e) {
161	System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
162	System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
163	}
164	startUp();
165	}
166	}
167
168	/**
169	* Starts the components as obtained from the configuration.
170	* This method calls the start() methods on all the components.
171	* If a component fails to start due to a CORBA communication
172	* problem, then it catches this and tries to start it again
173	* according to uk.ac.ukc.iscream.ComponentTimeout time.
174	*
175	* If the server dies and CORBA connections are lost, this method
176	* is called again.
177	*/
178	private static void startUp() {
179	// now we try and start the beast up
180	boolean tryAgain = true;
181	Component component = null;
182
183	// keep trying until we've started all the components.
184	// maybe add support for a limited number of retries
185	while(tryAgain) {
186	Iterator i = _componentsToStart.iterator();
187	ArrayList failedComponents = new ArrayList();
188	// go through all the components
189	while(i.hasNext()) {
190	try {
191	component = (Component) i.next();
192	System.out.println(toString + ": starting component - " + component.toString());
193
194	// start the component
195	component.start();
196
197	// if we get this then there was a problem
198	// that we can't recover from
199	} catch (ComponentStartException e) {
200	System.err.println(toString + ": ERROR starting component - " + component.toString());
201	System.err.println(toString + ": component reports - " + e.getMessage());
202	System.exit(1);
203
204	// if we get this exception then we've tried
205	// to talk to something which may not be up yet
206	// so we want to try again in a minute
207	} catch(ComponentCORBAException e2) {
208	System.err.println(toString + ": WARNING Component reported CORBA communications failure");
209	System.err.println(toString + ": This could be because it can't communicate with components it needs.");
210	System.err.println(toString + ": component reports - " + e2.getMessage());
211
212	// make a list of the failed components
213	failedComponents.add(component);
214	}
215	}
216
217	// if we had some failed components that we can retry
218	if (failedComponents.size() > 0) {
219	System.err.println(toString + ": WARNING One or more components failed to start correctly.");
220	System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
221
222	// our list is now the failed list
223	_componentsToStart = failedComponents;
224
225	// sleep for a given timeout
226	try {
227	Thread.sleep(_startTimeout * 1000);
228	} catch (InterruptedException e) {
229	// we're not bothered
230	}
231	// otherwise we started everything
232	} else {
233	// so we set to exit the loop
234	tryAgain = false;
235	}
236	}
237
238	System.out.println(toString + ": running");
239	}
240
241	/**
242	* A simple method to print the usage of this class.
243	* It never returns, but instead exits to the system
244	* with a value 1, to indicate the system did not start
245	* properly.
246	*/
247	public static void usage() {
248	System.out.println("USAGE: java uk.ac.ukc.iscream.componentmanager.ComponentManager <option>");
249	System.out.println(" or: java -jar iscream.jar <option>");
250	System.out.println("WHERE <option>:");
251	System.out.println(" -l <filename> - the location of initial system properties");
252	System.out.println(" the default is ./etc/default.properties");
253	System.out.println(" -f <name> - the name of the filter (if there is one configured");
254	System.out.println(" -h - this help screen");
255	System.exit(1);
256	}
257
258	//---CONSTRUCTORS---
259
260	//---PUBLIC METHODS---
261
262	//---PRIVATE METHODS---
263
264	//---ACCESSOR/MUTATOR METHODS---
265
266	//---ATTRIBUTES---
267
268	//---STATIC ATTRIBUTES---
269
270	private static ArrayList _componentsToStart;
271	private static int _startTimeout = 0;
272
273	}