001/**
002 * Copyright 2003-2004 The Apache Software Foundation
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package net.dpml.cli;
017
018import java.util.Comparator;
019import java.util.Set;
020
021/**
022 * An Option representing a choice or group of Options in the form "-a|-b|-c".
023 */
024public interface Group extends Option 
025{
026    /**
027     * Appends usage information to the specified StringBuffer
028     * 
029     * @param buffer the buffer to append to
030     * @param helpSettings a set of display settings @see DisplaySetting
031     * @param comp a comparator used to sort the Options
032     * @param separator the String used to separate member Options 
033     */
034    void appendUsage(
035        final StringBuffer buffer,
036        final Set helpSettings,
037        final Comparator comp,
038        final String separator );
039
040    /**
041     * Indicates whether group members must be present for the CommandLine to be
042     * valid.
043     *
044     * @see #getMinimum()
045     * @see #getMaximum()
046     * @return true iff the CommandLine will be invalid without at least one 
047     *         member option
048     */
049    boolean isRequired();
050
051    /**
052     * Retrieves the minimum number of members required for a valid Group
053     *
054     * @return the minimum number of members
055     */
056    int getMinimum();
057
058    /**
059     * Retrieves the maximum number of members acceptable for a valid Group
060     *
061     * @return the maximum number of members
062     */
063    int getMaximum();
064}