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package sun.net.dns;

import java.util.List;

The configuration of the client resolver.
A ResolverConfiguration is a singleton that represents the configuration of the client resolver. The ResolverConfiguration is opened by invoking the open method. 
Since:
1.4/**
 * The configuration of the client resolver.
 *
 * <p>A ResolverConfiguration is a singleton that represents the
 * configuration of the client resolver. The ResolverConfiguration
 * is opened by invoking the {@link #open() open} method.
 *
 * @since 1.4
 */

public abstract class ResolverConfiguration {

    private static final Object lock = new Object();

    private static ResolverConfiguration provider;

    protected ResolverConfiguration() { }

    
Opens the resolver configuration.
Returns:
the resolver configuration/**
     * Opens the resolver configuration.
     *
     * @return the resolver configuration
     */
    public static ResolverConfiguration open() {
        synchronized (lock) {
            if (provider == null) {
                provider = new sun.net.dns.ResolverConfigurationImpl();
            }
            return provider;
        }
    }

    
Returns a list corresponding to the domain search path. The list is ordered by the search order used for host name lookup. Each element in the list returns a String containing a domain name or suffix. 
Returns:
list of domain names/**
     * Returns a list corresponding to the domain search path. The
     * list is ordered by the search order used for host name lookup.
     * Each element in the list returns a {@link java.lang.String}
     * containing a domain name or suffix.
     *
     * @return list of domain names
     */
    public abstract List<String> searchlist();

    
Returns a list of name servers used for host name lookup. Each element in the list returns a String containing the textual representation of the IP address of the name server. 
Returns:
list of the name servers/**
     * Returns a list of name servers used for host name lookup.
     * Each element in the list returns a {@link java.lang.String}
     * containing the textual representation of the IP address of
     * the name server.
     *
     * @return list of the name servers
     */
    public abstract List<String> nameservers();


    
Options representing certain resolver variables of a ResolverConfiguration. /**
     * Options representing certain resolver variables of
     * a {@link ResolverConfiguration}.
     */
    public abstract static class Options {

        
Returns the maximum number of attempts the resolver
will connect to each name server before giving up
and returning an error.
Returns:
the resolver attempts value or -1 is unknown/**
         * Returns the maximum number of attempts the resolver
         * will connect to each name server before giving up
         * and returning an error.
         *
         * @return the resolver attempts value or -1 is unknown
         */
        public int attempts() {
            return -1;
        }

        
Returns the basic retransmit timeout, in milliseconds,
used by the resolver. The resolver will typically use
an exponential backoff algorithm where the timeout is
doubled for every retransmit attempt. The basic
retransmit timeout, returned here, is the initial
timeout for the exponential backoff algorithm.
Returns:
the basic retransmit timeout value or -1
        if unknown/**
         * Returns the basic retransmit timeout, in milliseconds,
         * used by the resolver. The resolver will typically use
         * an exponential backoff algorithm where the timeout is
         * doubled for every retransmit attempt. The basic
         * retransmit timeout, returned here, is the initial
         * timeout for the exponential backoff algorithm.
         *
         * @return the basic retransmit timeout value or -1
         *         if unknown
         */
        public int retrans() {
            return -1;
        }
    }

    
Returns the Options for the resolver. 
Returns:
options for the resolver/**
     * Returns the {@link #Options} for the resolver.
     *
     * @return options for the resolver
     */
    public abstract Options options();
}