/*

 * Copyright (c) 2000, 2012, 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

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 */

package com.sun.tools.javadoc.main;

import static com.sun.tools.javac.code.Flags.*;

/**

 *   A class whose instances are filters over Modifier bits.

 *   Filtering is done by returning boolean values.

 *   Classes, methods and fields can be filtered, or filtering

 *   can be done directly on modifier bits.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 *

 *   @see com.sun.tools.javac.code.Flags

 *   @author Robert Field

 */

public class ModifierFilter {

    /**

    * Package private access.

    * A "pseudo-" modifier bit that can be used in the

    * constructors of this class to specify package private

    * access. This is needed since there is no Modifier.PACKAGE.

    */

    public static final long PACKAGE = 0x8000000000000000L;

    /**

    * All access modifiers.

    * A short-hand set of modifier bits that can be used in the

    * constructors of this class to specify all access modifiers,

    * Same as PRIVATE | PROTECTED | PUBLIC | PACKAGE.

    */

    public static final long ALL_ACCESS =

                PRIVATE | PROTECTED | PUBLIC | PACKAGE;

    private long oneOf;

    private long must;

    private long cannot;

    private static final int ACCESS_BITS = PRIVATE | PROTECTED | PUBLIC;

    /**

     * Constructor - Specify a filter.

     *

     * @param   oneOf   If zero, everything passes the filter.

     *                  If non-zero, at least one of the specified

     *                  bits must be on in the modifier bits to

     *                  pass the filter.

     */

    public ModifierFilter(long oneOf) {

        this(oneOf, 0, 0);

    }

    /**

     * Constructor - Specify a filter.

     * For example, the filter below  will only pass synchronized

     * methods that are private or package private access and are

     * not native or static.

     * <pre>

     * ModifierFilter(  Modifier.PRIVATE | ModifierFilter.PACKAGE,

     *                  Modifier.SYNCHRONIZED,

     *                  Modifier.NATIVE | Modifier.STATIC)

     * </pre><p>

     * Each of the three arguments must either be

     * zero or the or'ed combination of the bits specified in the

     * class Modifier or this class. During filtering, these values

     * are compared against the modifier bits as follows:

     *

     * @param   oneOf   If zero, ignore this argument.

     *                  If non-zero, at least one of the bits must be on.

     * @param   must    All bits specified must be on.

     * @param   cannot  None of the bits specified can be on.

     */

    public ModifierFilter(long oneOf, long must, long cannot) {

        this.oneOf = oneOf;

        this.must = must;

        this.cannot = cannot;

    }

    /**

     * Filter on modifier bits.

     *

     * @param   modifierBits    Bits as specified in the Modifier class

     *

     * @return                  Whether the modifierBits pass this filter.

     */

    public boolean checkModifier(int modifierBits) {

        // Add in the "pseudo-" modifier bit PACKAGE, if needed

        long fmod = ((modifierBits & ACCESS_BITS) == 0) ?

                        modifierBits | PACKAGE :

                        modifierBits;

        return ((oneOf == 0) || ((oneOf & fmod) != 0)) &&

                ((must & fmod) == must) &&

                ((cannot & fmod) == 0);

    }

} // end ModifierFilter