ActionType.java

package org.apache.maven.changes;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

/*
 * Copyright 2001-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Action type enumeration.
 *
 * @author <a href="snicoll@apache.org">Stephane Nicoll</a>
 * @version $Id$
 */
public final class ActionType
    implements Comparable
{

    private static final Map types = new HashMap();

    /**
     * An action representing a fix.
     */
    public static final ActionType FIX = newActionType( "fix", 1 );

    /**
     * An action representing a new feature.
     */
    public static final ActionType ADD = newActionType( "add", 2 );

    /**
     * An action representing an improvement.
     */
    public static final ActionType UPDATE = newActionType( "update", 3 );

    /**
     * An action representing a removal.
     */
    public static final ActionType REMOVE = newActionType( "remove", 4 );


    /**
     * Returns the <code>ActionType</code> based on its name.
     *
     * @param name the name of the action
     * @return the action type or null if no such type exists.
     */
    public static ActionType getActionType( final String name )
    {
        if ( name == null )
        {
            throw new NullPointerException( "name could not be null." );
        }
        else
        {
            return (ActionType) types.get( name.toLowerCase() );
        }
    }

    /**
     * Returns a <tt>Collection</tt> of supported action types.
     *
     * @return the supported action types
     */
    public static Collection getActionTypes()
    {
        return types.values();
    }

    private static ActionType newActionType( String name, int position )
    {
        ActionType at = new ActionType( name, position );
        types.put( name, at );

        return at;
    }

    private final String name;

    private final Integer position;

    private ActionType( String name, int position )
    {
        this.name = name;
        this.position = new Integer( position );
    }

    public int compareTo( Object o )
    {
        if ( o == null )
        {
            throw new NullPointerException( "Could not compare to null." );
        }
        if ( ActionType.class.isInstance( o ) )
        {
            ActionType iat = (ActionType) o;
            return position.compareTo( iat.position );
        }
        else
        {
            throw new IllegalArgumentException(
                "Could not compare with[" + o.getClass().getName() + "] " + "expected[" + getClass().getName() + "]" );
        }
    }

    public String toString()
    {
        return name;
    }

    public boolean equals( Object o )
    {
        if ( this == o )
        {
            return true;
        }
        if ( o == null || getClass() != o.getClass() )
        {
            return false;
        }

        final ActionType that = (ActionType) o;

        if ( name != null ? !name.equals( that.name ) : that.name != null )
        {
            return false;
        }

        return true;
    }

    public int hashCode()
    {
        return ( name != null ? name.hashCode() : 0 );
    }
}