SMACK-225 Converted abstract class to interface, added missing hashcode method, fixed typos and some minor name changes and added licensing text

git-svn-id: http://svn.igniterealtime.org/svn/repos/smack/branches/smack_3_3_0@13600 b35dd754-fafc-0310-a699-88a17e54d16e

source/org/jivesoftware/smack/util/dns/DNSJavaResolver.java

@@ -22,18 +22,19 @@ import org.xbill.DNS.Lookup;
 import org.xbill.DNS.Record;
 import org.xbill.DNS.Type;
 
-public class DNSJavaResolver extends DNSResolver {
+/**
+ * This implementation uses the <a href="http://www.dnsjava.org/">dnsjava</a> implementation for resolving DNS addresses.
+ *
+ */
+public class DNSJavaResolver implements DNSResolver {
     
-    private static DNSJavaResolver instance;
+    private static DNSJavaResolver instance = new DNSJavaResolver();
     
     private DNSJavaResolver() {
         
     }
     
     public static DNSResolver getInstance() {
-        if (instance == null) {
-            instance = new DNSJavaResolver();
-        }
         return instance;
     }
 

source/org/jivesoftware/smack/util/dns/DNSResolver.java

@@ -17,8 +17,17 @@ package org.jivesoftware.smack.util.dns;
 
 import java.util.List;
 
-public abstract class DNSResolver {
+/**
+ * Implementations of this interface define a class that is capable of resolving DNS addresses.
+ *
+ */
+public interface DNSResolver {
 
-    public abstract List<SRVRecord> lookupSRVRecords(String name);
+    /**
+     * Gets a list of service records for the specified service.
+     * @param name The symbolic name of the service.
+     * @return The list of SRV records mapped to the service name.
+     */
+    List<SRVRecord> lookupSRVRecords(String name);
 
 }

source/org/jivesoftware/smack/util/dns/HostAddress.java

@@ -23,10 +23,10 @@ public class HostAddress {
     /**
      * Creates a new HostAddress with the given FQDN. The port will be set to the default XMPP client port: 5222
      * 
-     * @param fqdn
-     * @throws IllegalArgumentException
+     * @param fqdn Fully qualified domain name.
+     * @throws IllegalArgumentException If the fqdn is null.
      */
-    public HostAddress(String fqdn) throws IllegalArgumentException {
+    public HostAddress(String fqdn) {
         if (fqdn == null)
             throw new IllegalArgumentException("FQDN is null");
         if (fqdn.charAt(fqdn.length() - 1) == '.') {
@@ -39,7 +39,14 @@ public class HostAddress {
         this.port = 5222;
     }
 
-    public HostAddress(String fqdn, int port) throws IllegalArgumentException {
+    /**
+     * Creates a new HostAddress with the given FQDN. The port will be set to the default XMPP client port: 5222
+     * 
+     * @param fqdn Fully qualified domain name.
+     * @param port The port to connect on.
+     * @throws IllegalArgumentException If the fqdn is null or port is out of valid range (0 - 65535).
+     */
+    public HostAddress(String fqdn, int port) {
         this(fqdn);
         if (port < 0 || port > 65535)
             throw new IllegalArgumentException(
@@ -60,10 +67,12 @@ public class HostAddress {
         this.exception = e;
     }
 
+    @Override
     public String toString() {
         return fqdn + ":" + port;
     }
 
+    @Override
     public boolean equals(Object o) {
         if (this == o) {
             return true;
@@ -80,6 +89,13 @@ public class HostAddress {
         return port == address.port;
     }
 
+    @Override
+    public int hashCode() {
+        int result = 1;
+        result = 37 * result + fqdn.hashCode();
+        return result * 37 + port;
+    }
+
     public String getErrorMessage() {
         String error;
         if (exception == null) {

source/org/jivesoftware/smack/util/dns/JavaxResolver.java

@@ -28,12 +28,12 @@ import javax.naming.directory.InitialDirContext;
 import org.jivesoftware.smack.util.DNSUtil;
 
 /**
- * A DNS resolver (mostly for SRV records), which makes use of the API provided in the javax.* namepsace.
+ * A DNS resolver (mostly for SRV records), which makes use of the API provided in the javax.* namespace.
  * 
  * @author Florian Schmaus
  *
  */
-public class JavaxResolver extends DNSResolver {
+public class JavaxResolver implements DNSResolver {
     
     private static JavaxResolver instance;
     private static DirContext dirContext;
@@ -48,14 +48,14 @@ public class JavaxResolver extends DNSResolver {
         }
 
         // Try to set this DNS resolver as primary one
-        DNSUtil.setDNSResolver(maybeGetInstance());
+        DNSUtil.setDNSResolver(getInstance());
     }
     
     private JavaxResolver() {
         
     }
     
-    public static DNSResolver maybeGetInstance() {
+    public static DNSResolver getInstance() {
         if (instance == null && isSupported()) {
             instance = new JavaxResolver();
         }

source/org/jivesoftware/smack/util/dns/SRVRecord.java

@@ -29,13 +29,13 @@ public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
     /**
      * Create a new SRVRecord
      * 
-     * @param fqdn
-     * @param port
-     * @param priority
-     * @param weight
-     * @throws IllegalArgumentException
+     * @param fqdn Fully qualified domain name
+     * @param port The connection port
+     * @param priority Priority of the target host
+     * @param weight Relative weight for records with same priority
+     * @throws IllegalArgumentException fqdn is null or any other field is not in valid range (0-65535).
      */
-    public SRVRecord(String fqdn, int port, int priority, int weight) throws IllegalArgumentException {
+    public SRVRecord(String fqdn, int port, int priority, int weight) {
         super(fqdn, port);
         if (weight < 0 || weight > 65535)
             throw new IllegalArgumentException(
@@ -60,6 +60,7 @@ public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
         return weight;
     }
 
+    @Override
     public int compareTo(SRVRecord other) {
         // According to RFC2782,
         // "[a] client MUST attempt to contact the target host with the lowest-numbered priority it can reach".
@@ -71,6 +72,7 @@ public class SRVRecord extends HostAddress implements Comparable<SRVRecord> {
         return res;
     }
 
+    @Override
     public String toString() {
         return super.toString() + " prio:" + priority + ":w:" + weight;
     }