server/filter/ServiceCheckSkeleton.java

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

//---IMPORTS---
import java.net.*;
import java.io.*;

/**
 * A skeleton class for Service Checks to extend.
 *
 * @author  $Author$
 * @version $Id$
 */
public abstract class ServiceCheckSkeleton implements PluginServiceCheck {

//---FINAL ATTRIBUTES---
    
//---STATIC METHODS---

//---CONSTRUCTORS---

//---PUBLIC METHODS---
    
    /**
     * Runs a service check on a given hostname.
     *
     * @param hostname The hostname to check
     */
    public abstract String runServiceCheck(String hostname);
    
    /**
     * Checks if a service is returning a valid response, and
     * constructs suitable XML for inclusion in a packet.
     *
     * @param hostname The hostname to query
     * @param port The port to query
     * @param expectedSubString The String to look for in the response
     * @param XMLTag The name of the tag to be put in the XML
     * @return The String of XML with the response information
     */
    protected String checkService(String hostname, int port, String expectedSubString, String XMLTag) {
        String message, status;
        try {
            // connect and get response
            String response = connectToService(hostname, port);
            // check if the expected text is in the response
            if(response.indexOf(expectedSubString) != -1) {
                status = "0";
                message = "Good Header received: "+response;
            }
            else {
                status = "1";
                message = "Bad Header received: "+response;
            }
        } catch (IOException e) {
            // connect failed
            status = "1";
            message = "Service check failed to establish connection to host: " + e.getMessage();
        }
        return "<"+XMLTag+" status=\"" + status + "\" message=\"" + message + "\"></"+XMLTag+">";
    }
    
    /**
     * Connects to a service and returns the first line of text.
     *
     * @param hostname The hostname of the service to check
     * @param port The port of the service to check
     * @return The first line of text given
     * @throws IOException if the connection fails for some reason
     */
    protected String connectToService(String hostname, int port) throws IOException {
        // connect
        Socket socket = new Socket(hostname, 22);
        BufferedReader socketIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        // read first line
        String response = socketIn.readLine();
        // close
        socketIn.close();
        socket.close();
        // return first line
        return response;
    }
    
    /**
     * Used to query the Service Check to see what it does.
     *
     * @return the String representation of what the Service Check does
     */
    public String getDescription(){
        return DESC;
    }

//---PRIVATE METHODS---

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

//---ATTRIBUTES---

    private String DESC;

//---STATIC ATTRIBUTES---

}
Revision:	1.1
Committed:	Wed Mar 7 23:19:13 2001 UTC (23 years, 2 months ago) by tdb
Branch:	MAIN
Log Message:	Made an abstract skeleton class for the service checks. They all do very similar things, so it seemed worth putting all the behaviour in one place. This also has another advantage, namely that service checks are now much quicker to produce, and that in the future the checks could even be moved to a general checker that reads from the configuration.
#	User	Rev	Content
1	tdb	1.1	//---PACKAGE DECLARATION---
2			package uk.ac.ukc.iscream.filter;
3
4			//---IMPORTS---
5			import java.net.*;
6			import java.io.*;
7
8			/**
9			* A skeleton class for Service Checks to extend.
10			*
11			* @author $Author$
12			* @version $Id$
13			*/
14			public abstract class ServiceCheckSkeleton implements PluginServiceCheck {
15
16			//---FINAL ATTRIBUTES---
17
18			//---STATIC METHODS---
19
20			//---CONSTRUCTORS---
21
22			//---PUBLIC METHODS---
23
24			/**
25			* Runs a service check on a given hostname.
26			*
27			* @param hostname The hostname to check
28			*/
29			public abstract String runServiceCheck(String hostname);
30
31			/**
32			* Checks if a service is returning a valid response, and
33			* constructs suitable XML for inclusion in a packet.
34			*
35			* @param hostname The hostname to query
36			* @param port The port to query
37			* @param expectedSubString The String to look for in the response
38			* @param XMLTag The name of the tag to be put in the XML
39			* @return The String of XML with the response information
40			*/
41			protected String checkService(String hostname, int port, String expectedSubString, String XMLTag) {
42			String message, status;
43			try {
44			// connect and get response
45			String response = connectToService(hostname, port);
46			// check if the expected text is in the response
47			if(response.indexOf(expectedSubString) != -1) {
48			status = "0";
49			message = "Good Header received: "+response;
50			}
51			else {
52			status = "1";
53			message = "Bad Header received: "+response;
54			}
55			} catch (IOException e) {
56			// connect failed
57			status = "1";
58			message = "Service check failed to establish connection to host: " + e.getMessage();
59			}
60			return "<"+XMLTag+" status=\"" + status + "\" message=\"" + message + "\"></"+XMLTag+">";
61			}
62
63			/**
64			* Connects to a service and returns the first line of text.
65			*
66			* @param hostname The hostname of the service to check
67			* @param port The port of the service to check
68			* @return The first line of text given
69			* @throws IOException if the connection fails for some reason
70			*/
71			protected String connectToService(String hostname, int port) throws IOException {
72			// connect
73			Socket socket = new Socket(hostname, 22);
74			BufferedReader socketIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
75			// read first line
76			String response = socketIn.readLine();
77			// close
78			socketIn.close();
79			socket.close();
80			// return first line
81			return response;
82			}
83
84			/**
85			* Used to query the Service Check to see what it does.
86			*
87			* @return the String representation of what the Service Check does
88			*/
89			public String getDescription(){
90			return DESC;
91			}
92
93			//---PRIVATE METHODS---
94
95			//---ACCESSOR/MUTATOR METHODS---
96
97			//---ATTRIBUTES---
98
99			private String DESC;
100
101			//---STATIC ATTRIBUTES---
102
103			}