server/componentmanager/ComponentManager.java

//---PACKAGE DECLARATION---
package uk.org.iscream.componentmanager;

//---IMPORTS---
import java.util.*;
import java.io.*;
import uk.org.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.org.iscream.ComponentList
 *
 * @author  $Author: ajm4 $
 * @version $Id: ComponentManager.java,v 1.36 2001/03/19 03:36:18 ajm4 Exp $
 */
public class ComponentManager {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision: 1.36 $";
    
    /**
     * 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("-----------------------------------------");
        System.out.println("--- i-scream Server Component Manager ---");
        System.out.println("---   (c) 2001 The i-scream Project   ---");
        System.out.println("---    (http://www.i-scream.org.uk)   ---");
        System.out.println("-----------------------------------------");
        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.org.iscream.ComponentList");
        StringTokenizer st = new StringTokenizer(componentList, ";");
        _componentsToStart = new LinkedList();
        
        // 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.org.iscream.core.Core();
            } else if (componentName.equalsIgnoreCase("filtermanager")) {
                component = new uk.org.iscream.filtermanager.FilterManager();
            } else if (componentName.equalsIgnoreCase("rootfilter")) {
                component = new uk.org.iscream.rootfilter.RootFilter();
            } else if (componentName.equalsIgnoreCase("dbinterface")) {
                component = new uk.org.iscream.dbinterface.DBInterface();
            } else if (componentName.equalsIgnoreCase("clientinterface")) {
                component = new uk.org.iscream.clientinterface.ClientInterfaceMain();
            // note the passing of the Filter's name in its constructor
            } else if (componentName.equalsIgnoreCase("filter")) {
                component = new uk.org.iscream.filter.FilterMain(filterName);
            } else if (componentName.equalsIgnoreCase("client")) {
                component = new uk.org.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: "+componentName);
            }
        }
        
        

        // get the value for timeout
        
        String confTimeout = null;
        try {
            confTimeout = System.getProperty("uk.org.iscream.ComponentTimeout");
            confTimeout.trim();
            _startTimeout = Integer.parseInt(confTimeout);
        } catch (NumberFormatException e) {
            _startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
            System.err.println(toString + ": unable to read uk.org.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.
            // !! this doesn't appear to work !!
            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.org.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();
            LinkedList failedComponents = new LinkedList();
            // go through all the components
            while(i.hasNext()) {
                // get a refence to the component
                component = (Component) i.next();
                System.out.println(toString + ": dependency checking component - " + component.toString());
                
                // check it's dependencies
                boolean depOK = component.depCheck();
                if(depOK) {
                    System.out.println(toString + ": starting component - " + component.toString());
                    // it should be ok to start the component
                        try {    
                            // start the component
                        component.start();
                    } catch (ComponentStartException e) {
                        // if we get this then there was a problem
                        // that we can't recover from
                        System.err.println(toString + ": ERROR starting component - " + component.toString());
                        System.err.println(toString + ": component reports - " + e.getMessage());
                        System.exit(1);
                    }
                }
                else {
                    // it seems the depedencies failed
                    // so we want to try again after a delay
                    System.err.println(toString + ": WARNING Component reported dependency failure");
                    System.err.println(toString + ": This could be because it can't communicate with components it needs.");
                    
                    // 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.org.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 LinkedList _componentsToStart;
    private static int _startTimeout = 0;

}
Revision:	1.37
Committed:	Mon Mar 19 19:14:25 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
CVS Tags:	PROJECT_COMPLETION
Changes since 1.36:	+4 -4 lines
Log Message:	Changed a funny character (c) to a plain text (c).
#	Content
1	//---PACKAGE DECLARATION---
2	package uk.org.iscream.componentmanager;
3
4	//---IMPORTS---
5	import java.util.*;
6	import java.io.*;
7	import uk.org.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.org.iscream.ComponentList
16	*
17	* @author $Author: ajm4 $
18	* @version $Id: ComponentManager.java,v 1.36 2001/03/19 03:36:18 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: 1.36 $";
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("-----------------------------------------");
57	System.out.println("--- i-scream Server Component Manager ---");
58	System.out.println("--- (c) 2001 The i-scream Project ---");
59	System.out.println("--- (http://www.i-scream.org.uk) ---");
60	System.out.println("-----------------------------------------");
61	System.out.println("--- Starting System ---");
62
63	// get the command line args
64	String defaultProperties = DEFAULTPROPERTIES;
65	String filterName = null;
66	for(int i=0; i < args.length; i++) {
67	if(args[i].equals("-h")) {
68	usage();
69	}
70	else if(args[i].equals("-f")) {
71	i++; filterName = args[i];
72	}
73	else if(args[i].equals("-l")) {
74	i++; defaultProperties = args[i];
75	}
76	else {
77	usage();
78	}
79	}
80
81	// load the default properties file into the system properties
82	System.out.println(toString + ": initialising - using " + defaultProperties);
83	try {
84	Properties initProperties = new Properties(System.getProperties());
85	initProperties.load(new FileInputStream(new File(defaultProperties)));
86	System.setProperties(initProperties);
87	} catch (Exception e) {
88	System.err.println(toString + ": ERROR " + e.getMessage());
89	usage();
90	}
91
92	// continue to bring the system up
93	System.out.println(toString + ": coming up");
94
95	// start the ORB by initialising the ReferenceManager
96	ReferenceManager refman = ReferenceManager.getInstance();
97
98	// now the ORB is running, we need to activate our RootPOA
99	// so that we can start serving requests once servants start up
100	refman.activatePOA();
101
102	// get the list of components
103	String componentList = System.getProperty("uk.org.iscream.ComponentList");
104	StringTokenizer st = new StringTokenizer(componentList, ";");
105	_componentsToStart = new LinkedList();
106
107	// this could be done using reflection
108	// but..well..we don't ;-p
109	while (st.hasMoreTokens()){
110	String componentName = st.nextToken();
111	Component component = null;
112
113
114	// ### This is where the list of supported components is checked! ###
115	if (componentName.equalsIgnoreCase("core")) {
116	component = new uk.org.iscream.core.Core();
117	} else if (componentName.equalsIgnoreCase("filtermanager")) {
118	component = new uk.org.iscream.filtermanager.FilterManager();
119	} else if (componentName.equalsIgnoreCase("rootfilter")) {
120	component = new uk.org.iscream.rootfilter.RootFilter();
121	} else if (componentName.equalsIgnoreCase("dbinterface")) {
122	component = new uk.org.iscream.dbinterface.DBInterface();
123	} else if (componentName.equalsIgnoreCase("clientinterface")) {
124	component = new uk.org.iscream.clientinterface.ClientInterfaceMain();
125	// note the passing of the Filter's name in its constructor
126	} else if (componentName.equalsIgnoreCase("filter")) {
127	component = new uk.org.iscream.filter.FilterMain(filterName);
128	} else if (componentName.equalsIgnoreCase("client")) {
129	component = new uk.org.iscream.client.ClientMain();
130	}
131	// ### Add new component constructors in the above section! ###
132
133	// build the list of components to start
134	if (component != null) {
135	_componentsToStart.add(component);
136	} else {
137	System.err.println(toString + ": WARNING unsupported component not started: "+componentName);
138	}
139	}
140
141
142
143	// get the value for timeout
144
145	String confTimeout = null;
146	try {
147	confTimeout = System.getProperty("uk.org.iscream.ComponentTimeout");
148	confTimeout.trim();
149	_startTimeout = Integer.parseInt(confTimeout);
150	} catch (NumberFormatException e) {
151	_startTimeout = DEFAULT_COMPONENT_START_TIMEOUT;
152	System.err.println(toString + ": unable to read uk.org.iscream.ComponentTimeout value (" + confTimeout + "), using default!");
153	}
154	System.out.println(toString + ": using component start timeout of " + _startTimeout + " seconds");
155
156	// startup the system components
157	startUp();
158
159	// block on the ORB...in time, management functionality can be placed here.
160	// if we detect a CORBA communication error, we'll restart all the components.
161	// !! this doesn't appear to work !!
162	while(true) {
163	try {
164	refman.getORB().run();
165	} catch (org.omg.CORBA.COMM_FAILURE e) {
166	System.out.println(toString + ": WARNING CORBA communications failure - " + e.getMessage());
167	System.out.println(toString + ": WARNING CORBA connections have been lost - attempting to restart!");
168	}
169	startUp();
170	}
171	}
172
173	/**
174	* Starts the components as obtained from the configuration.
175	* This method calls the start() methods on all the components.
176	* If a component fails to start due to a CORBA communication
177	* problem, then it catches this and tries to start it again
178	* according to uk.org.iscream.ComponentTimeout time.
179	*
180	* If the server dies and CORBA connections are lost, this method
181	* is called again.
182	*/
183	private static void startUp() {
184	// now we try and start the beast up
185	boolean tryAgain = true;
186	Component component = null;
187
188	// keep trying until we've started all the components.
189	// maybe add support for a limited number of retries
190	while(tryAgain) {
191	Iterator i = _componentsToStart.iterator();
192	LinkedList failedComponents = new LinkedList();
193	// go through all the components
194	while(i.hasNext()) {
195	// get a refence to the component
196	component = (Component) i.next();
197	System.out.println(toString + ": dependency checking component - " + component.toString());
198
199	// check it's dependencies
200	boolean depOK = component.depCheck();
201	if(depOK) {
202	System.out.println(toString + ": starting component - " + component.toString());
203	// it should be ok to start the component
204	try {
205	// start the component
206	component.start();
207	} catch (ComponentStartException e) {
208	// if we get this then there was a problem
209	// that we can't recover from
210	System.err.println(toString + ": ERROR starting component - " + component.toString());
211	System.err.println(toString + ": component reports - " + e.getMessage());
212	System.exit(1);
213	}
214	}
215	else {
216	// it seems the depedencies failed
217	// so we want to try again after a delay
218	System.err.println(toString + ": WARNING Component reported dependency failure");
219	System.err.println(toString + ": This could be because it can't communicate with components it needs.");
220
221	// make a list of the failed components
222	failedComponents.add(component);
223	}
224	}
225
226	// if we had some failed components that we can retry
227	if (failedComponents.size() > 0) {
228	System.err.println(toString + ": WARNING One or more components failed to start correctly.");
229	System.err.println(toString + ": Will try again in " + _startTimeout + " seconds");
230
231	// our list is now the failed list
232	_componentsToStart = failedComponents;
233
234	// sleep for a given timeout
235	try {
236	Thread.sleep(_startTimeout * 1000);
237	} catch (InterruptedException e) {
238	// we're not bothered
239	}
240	// otherwise we started everything
241	} else {
242	// so we set to exit the loop
243	tryAgain = false;
244	}
245	}
246
247	System.out.println(toString + ": running");
248	}
249
250	/**
251	* A simple method to print the usage of this class.
252	* It never returns, but instead exits to the system
253	* with a value 1, to indicate the system did not start
254	* properly.
255	*/
256	public static void usage() {
257	System.out.println("USAGE: java uk.org.iscream.componentmanager.ComponentManager <option>");
258	System.out.println(" or: java -jar iscream.jar <option>");
259	System.out.println("WHERE <option>:");
260	System.out.println(" -l <filename> - the location of initial system properties");
261	System.out.println(" the default is ./etc/default.properties");
262	System.out.println(" -f <name> - the name of the filter (if there is one configured");
263	System.out.println(" -h - this help screen");
264	System.exit(1);
265	}
266
267	//---CONSTRUCTORS---
268
269	//---PUBLIC METHODS---
270
271	//---PRIVATE METHODS---
272
273	//---ACCESSOR/MUTATOR METHODS---
274
275	//---ATTRIBUTES---
276
277	//---STATIC ATTRIBUTES---
278
279	private static LinkedList _componentsToStart;
280	private static int _startTimeout = 0;
281
282	}