/*
 * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.security.ssl;

import java.util.*;

A list of ProtocolVersions. Also maintains the list of supported protocols.
Instances of this class are immutable. Some member variables are final
and can be accessed directly without method accessors.
Author:
 Andreas Sterbenz
Since:
  1.4.1/**
 * A list of ProtocolVersions. Also maintains the list of supported protocols.
 * Instances of this class are immutable. Some member variables are final
 * and can be accessed directly without method accessors.
 *
 * @author  Andreas Sterbenz
 * @since   1.4.1
 */
final class ProtocolList {

    // the sorted protocol version list
    private final ArrayList<ProtocolVersion> protocols;

    private String[] protocolNames;

    // the minimum and maximum ProtocolVersions in this list
    final ProtocolVersion min, max;

    // the format for the hello version to use
    final ProtocolVersion helloVersion;

    ProtocolList(String[] names) {
        this(convert(names));
    }

    ProtocolList(ArrayList<ProtocolVersion> versions) {
        this.protocols = versions;

        if ((protocols.size() == 1) &&
                protocols.contains(ProtocolVersion.SSL20Hello)) {
            throw new IllegalArgumentException("SSLv2Hello cannot be " +
                "enabled unless at least one other supported version " +
                "is also enabled.");
        }

        if (protocols.size() != 0) {
            Collections.sort(protocols);
            min = protocols.get(0);
            max = protocols.get(protocols.size() - 1);
            helloVersion = protocols.get(0);
        } else {
            min = ProtocolVersion.NONE;
            max = ProtocolVersion.NONE;
            helloVersion = ProtocolVersion.NONE;
        }
    }

    private static ArrayList<ProtocolVersion> convert(String[] names) {
        if (names == null) {
            throw new IllegalArgumentException("Protocols may not be null");
        }

        ArrayList<ProtocolVersion> versions = new ArrayList<ProtocolVersion>(3);
        for (int i = 0; i < names.length; i++ ) {
            ProtocolVersion version = ProtocolVersion.valueOf(names[i]);
            if (versions.contains(version) == false) {
                versions.add(version);
            }
        }

        return versions;
    }

    
Return whether this list contains the specified protocol version.
SSLv2Hello is not a real protocol version we support, we always
return false for it.
/**
     * Return whether this list contains the specified protocol version.
     * SSLv2Hello is not a real protocol version we support, we always
     * return false for it.
     */
    boolean contains(ProtocolVersion protocolVersion) {
        if (protocolVersion == ProtocolVersion.SSL20Hello) {
            return false;
        }
        return protocols.contains(protocolVersion);
    }

    
Return a reference to the internal Collection of CipherSuites.
The Collection MUST NOT be modified.
/**
     * Return a reference to the internal Collection of CipherSuites.
     * The Collection MUST NOT be modified.
     */
    Collection<ProtocolVersion> collection() {
        return protocols;
    }

    
Select a protocol version from the list.
Return the lower of the protocol version of that suggested by
the protocolVersion and the highest version of this
protocol list, or null if no protocol version is available.
The method is used by TLS server to negotiated the protocol
version between client suggested protocol version in the
client hello and protocol versions supported by the server.
/**
     * Select a protocol version from the list.
     *
     * Return the lower of the protocol version of that suggested by
     * the <code>protocolVersion</code> and the highest version of this
     * protocol list, or null if no protocol version is available.
     *
     * The method is used by TLS server to negotiated the protocol
     * version between client suggested protocol version in the
     * client hello and protocol versions supported by the server.
     */
    ProtocolVersion selectProtocolVersion(ProtocolVersion protocolVersion) {
        ProtocolVersion selectedVersion = null;
        for (ProtocolVersion pv : protocols) {
            if (pv.v > protocolVersion.v) {
                break;  // Safe to break here as this.protocols is sorted
            }
            selectedVersion = pv;
        }

        return selectedVersion;
    }

    
Return an array with the names of the ProtocolVersions in this list.
/**
     * Return an array with the names of the ProtocolVersions in this list.
     */
    synchronized String[] toStringArray() {
        if (protocolNames == null) {
            protocolNames = new String[protocols.size()];
            int i = 0;
            for (ProtocolVersion version : protocols) {
                protocolNames[i++] = version.name;
            }
        }
        return protocolNames.clone();
    }

    public String toString() {
        return protocols.toString();
    }
}