server/ACL/ACL.java

//---PACKAGE DECLARATION---
//package uk.org.iscream.cms.server.util;

//---IMPORTS---
import uk.org.iscream.cms.server.util.*;
import java.util.LinkedList;
import java.util.Iterator;
import java.net.InetAddress;

/**
 * Access Control List for use primarily
 * with the ACLServerSocket. It could, however
 * have other uses as it has a fairly generic
 * behaviour. Rules are added using the add
 * method, and then checks can be made using
 * the relevant check method.
 *
 * @author  $Author$
 * @version $Id$
 */
public class ACL {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public static final String REVISION = "$Revision$";
    
    /**
     * static to be used when adding an ALLOW rule to the ACL.
     */
    public static final boolean ALLOW = true;
    
    /**
     * static to be used when adding a DENY rule to the ACL.
     */
    public static final boolean DENY = false;

//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Construct a new Access Control List. The default
     * mode is to ALLOW anything that isn't explicitly
     * blocked by a rule.
     */
    public ACL() {
        // default to ACL.ALLOW
        this(ACL.ALLOW);
    }
    
    /**
     * Construct a new Access Control List with a given
     * default mode. This mode specifies what should
     * happen if a check does not match any rules.
     *
     * @param defaultMode the default mode for non-matched checks
     */
    public ACL(boolean defaultMode) {
        _defaultMode = defaultMode;
    }

//---PUBLIC METHODS---

    /**
     * Add a new rule to the ACL immediately after the
     * previous rule. The rule can either be an ACL.ALLOW
     * rule, or an ACL.DENY rule. The expression can
     * contain a wildcard (a * only). Rules can only be
     * added to the end of the list.
     *
     * param allow whether this is an ALLOW or DENY rule
     * param expression what this rule matches using wildcards
     */
    public void add(boolean allow, String expression) {
        _acl.add(new ACLRule(allow, expression));
    }
    
    /**
     * Check to see if a string is permitted by the
     * ACL. Useful for testing, and non-Socket uses
     * of this class.
     *
     * @param address the string to check
     * @return whether the address was permitted by the ACL
     */
    public boolean check(String address) {
        Iterator i = _acl.iterator();
        while(i.hasNext()) {
            ACLRule item = (ACLRule) i.next();
            if(StringUtils.wildcardCheck(address, item._expression)) {
                return item._allow;
            }
        }
        return _defaultMode;
    }
    
    /**
     * Check to see if an InetAddress is permitted
     * by the ACL. Perfect for Socket uses of this
     * class. It should be made clear that this will
     * check both the hostname AND IP address against
     * each rule in turn. The hostname will always be
     * checked BEFORE the IP address.
     *
     * @param address the InetAddress to check
     * @return whether the InetAddress was permitted by the ACL
     */
    public boolean check(InetAddress address) {
        Iterator i = _acl.iterator();
        while(i.hasNext()) {
            ACLRule item = (ACLRule) i.next();
            if(StringUtils.wildcardCheck(address.getHostName(), item._expression)) {
                return item._allow;
            }
            if(StringUtils.wildcardCheck(address.getHostAddress(), item._expression)) {
                return item._allow;
            }
        }
        return _defaultMode;
    }
    
    /**
     * Gets the ACL as a String for debugging.
     *
     * @return A String representation of this ACL.
     */
    public String getStringACL() {
        String acl = "";
        Iterator i = _acl.iterator();
        while(i.hasNext()) {
            ACLRule item = (ACLRule) i.next();
            if(item._allow) {
                acl += "ALLOW:" + item._expression + " ";
            }
            else {
                acl += "DENY:" + item._expression + " ";
            }
        }
        return acl.substring(0, acl.length()-1);
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * This uses the uk.org.iscream.cms.server.util.FormatName class
     * to format the toString()
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return FormatName.getName(
            _name,
            getClass().getName(),
            REVISION);
    }

//---PRIVATE METHODS---

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

//---ATTRIBUTES---

    /**
     * This is the friendly identifier of the
     * component this class is running in.
     * eg, a Filter may be called "filter1",
     * If this class does not have an owning
     * component,  a name from the configuration
     * can be placed here.  This name could also
     * be changed to null for utility classes.
     */
    private String _name = null;
    
    /**
     * The ACL is stored in this LinkedList.
     * This is ideal as the list is always searched
     * from beginning to end in an iterative fashion.
     */
    private LinkedList _acl = new LinkedList();
    
    /**
     * The default mode of this ACL.
     */
    private boolean _defaultMode;

//---STATIC ATTRIBUTES---

//---INNER CLASSES---

    /**
     * Wrapper class for an ACL rule.
     */
    private class ACLRule {
        
        /**
         * Construct an ACL rule.
         *
         * @param allow whether this is an ALLOW or DENY rule
         * @param expression what this rule matches
         */
        private ACLRule(boolean allow, String expression) {
            _allow = allow;
            _expression = expression;
        }
        
        /**
         * Whether this is an ALLOW or DENY rule.
         */
        private boolean _allow;
        
        /**
         * What this rule matches.
         */
        private String _expression;
        
    }

}
Revision:	1.2
Committed:	Thu Dec 20 00:59:54 2001 UTC (22 years, 11 months ago) by tdb
Branch:	MAIN
Changes since 1.1:	+93 -14 lines
Log Message:	Fully commented, and further testing in the Socket environment. Probably ready to integrate into the main source tree under the server util package.
#	Content
1	//---PACKAGE DECLARATION---
2	//package uk.org.iscream.cms.server.util;
3
4	//---IMPORTS---
5	import uk.org.iscream.cms.server.util.*;
6	import java.util.LinkedList;
7	import java.util.Iterator;
8	import java.net.InetAddress;
9
10	/**
11	* Access Control List for use primarily
12	* with the ACLServerSocket. It could, however
13	* have other uses as it has a fairly generic
14	* behaviour. Rules are added using the add
15	* method, and then checks can be made using
16	* the relevant check method.
17	*
18	* @author $Author$
19	* @version $Id$
20	*/
21	public class ACL {
22
23	//---FINAL ATTRIBUTES---
24
25	/**
26	* The current CVS revision of this class
27	*/
28	public static final String REVISION = "$Revision$";
29
30	/**
31	* static to be used when adding an ALLOW rule to the ACL.
32	*/
33	public static final boolean ALLOW = true;
34
35	/**
36	* static to be used when adding a DENY rule to the ACL.
37	*/
38	public static final boolean DENY = false;
39
40	//---STATIC METHODS---
41
42	//---CONSTRUCTORS---
43
44	/**
45	* Construct a new Access Control List. The default
46	* mode is to ALLOW anything that isn't explicitly
47	* blocked by a rule.
48	*/
49	public ACL() {
50	// default to ACL.ALLOW
51	this(ACL.ALLOW);
52	}
53
54	/**
55	* Construct a new Access Control List with a given
56	* default mode. This mode specifies what should
57	* happen if a check does not match any rules.
58	*
59	* @param defaultMode the default mode for non-matched checks
60	*/
61	public ACL(boolean defaultMode) {
62	_defaultMode = defaultMode;
63	}
64
65	//---PUBLIC METHODS---
66
67	/**
68	* Add a new rule to the ACL immediately after the
69	* previous rule. The rule can either be an ACL.ALLOW
70	* rule, or an ACL.DENY rule. The expression can
71	* contain a wildcard (a * only). Rules can only be
72	* added to the end of the list.
73	*
74	* param allow whether this is an ALLOW or DENY rule
75	* param expression what this rule matches using wildcards
76	*/
77	public void add(boolean allow, String expression) {
78	_acl.add(new ACLRule(allow, expression));
79	}
80
81	/**
82	* Check to see if a string is permitted by the
83	* ACL. Useful for testing, and non-Socket uses
84	* of this class.
85	*
86	* @param address the string to check
87	* @return whether the address was permitted by the ACL
88	*/
89	public boolean check(String address) {
90	Iterator i = _acl.iterator();
91	while(i.hasNext()) {
92	ACLRule item = (ACLRule) i.next();
93	if(StringUtils.wildcardCheck(address, item._expression)) {
94	return item._allow;
95	}
96	}
97	return _defaultMode;
98	}
99
100	/**
101	* Check to see if an InetAddress is permitted
102	* by the ACL. Perfect for Socket uses of this
103	* class. It should be made clear that this will
104	* check both the hostname AND IP address against
105	* each rule in turn. The hostname will always be
106	* checked BEFORE the IP address.
107	*
108	* @param address the InetAddress to check
109	* @return whether the InetAddress was permitted by the ACL
110	*/
111	public boolean check(InetAddress address) {
112	Iterator i = _acl.iterator();
113	while(i.hasNext()) {
114	ACLRule item = (ACLRule) i.next();
115	if(StringUtils.wildcardCheck(address.getHostName(), item._expression)) {
116	return item._allow;
117	}
118	if(StringUtils.wildcardCheck(address.getHostAddress(), item._expression)) {
119	return item._allow;
120	}
121	}
122	return _defaultMode;
123	}
124
125	/**
126	* Gets the ACL as a String for debugging.
127	*
128	* @return A String representation of this ACL.
129	*/
130	public String getStringACL() {
131	String acl = "";
132	Iterator i = _acl.iterator();
133	while(i.hasNext()) {
134	ACLRule item = (ACLRule) i.next();
135	if(item._allow) {
136	acl += "ALLOW:" + item._expression + " ";
137	}
138	else {
139	acl += "DENY:" + item._expression + " ";
140	}
141	}
142	return acl.substring(0, acl.length()-1);
143	}
144
145	/**
146	* Overrides the {@link java.lang.Object#toString() Object.toString()}
147	* method to provide clean logging (every class should have this).
148	*
149	* This uses the uk.org.iscream.cms.server.util.FormatName class
150	* to format the toString()
151	*
152	* @return the name of this class and its CVS revision
153	*/
154	public String toString() {
155	return FormatName.getName(
156	_name,
157	getClass().getName(),
158	REVISION);
159	}
160
161	//---PRIVATE METHODS---
162
163	//---ACCESSOR/MUTATOR METHODS---
164
165	//---ATTRIBUTES---
166
167	/**
168	* This is the friendly identifier of the
169	* component this class is running in.
170	* eg, a Filter may be called "filter1",
171	* If this class does not have an owning
172	* component, a name from the configuration
173	* can be placed here. This name could also
174	* be changed to null for utility classes.
175	*/
176	private String _name = null;
177
178	/**
179	* The ACL is stored in this LinkedList.
180	* This is ideal as the list is always searched
181	* from beginning to end in an iterative fashion.
182	*/
183	private LinkedList _acl = new LinkedList();
184
185	/**
186	* The default mode of this ACL.
187	*/
188	private boolean _defaultMode;
189
190	//---STATIC ATTRIBUTES---
191
192	//---INNER CLASSES---
193
194	/**
195	* Wrapper class for an ACL rule.
196	*/
197	private class ACLRule {
198
199	/**
200	* Construct an ACL rule.
201	*
202	* @param allow whether this is an ALLOW or DENY rule
203	* @param expression what this rule matches
204	*/
205	private ACLRule(boolean allow, String expression) {
206	_allow = allow;
207	_expression = expression;
208	}
209
210	/**
211	* Whether this is an ALLOW or DENY rule.
212	*/
213	private boolean _allow;
214
215	/**
216	* What this rule matches.
217	*/
218	private String _expression;
219
220	}
221
222	}