/*

 * Copyright (c) 2012, 2018, 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.

 *

 * 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 org.graalvm.compiler.debug;

import java.util.Comparator;

import jdk.internal.vm.compiler.collections.Pair;

/**

 * A key for a metric.

 */

public interface MetricKey {

    /**

     * Converts a given value for this key to a string, scaling it to a more useful unit of

     * measurement and appending a suffix indicating the unit where applicable. This representation

     * is intended for human consumption.

     */

    String toHumanReadableFormat(long value);

    /**

     * Converts a given value for this key to a CSV format intended for automated data processing.

     *

     * @param value

     * @return a pair where first is the {@code value} with any scaling conversion applied and

     *         second is the unit of measurement used for the first component (this will be the

     *         empty string for a simple counter)

     */

    Pair<String, String> toCSVFormat(long value);

    /**

     * Gets the name of this key.

     */

    String getName();

    /**

     * Comparator to sort keys by their names.

     */

    Comparator<MetricKey> NAME_COMPARATOR = new Comparator<MetricKey>() {

        @Override

        public int compare(MetricKey o1, MetricKey o2) {

            return o1.getName().compareTo(o2.getName());

        }

    };

    /**

     * Sets the documentation for this key.

     */

    MetricKey doc(String string);

    /**

     * Gets the name to use when listing keys. Note that this may be different from

     * {@link #getName()}.

     *

     * @return {@code null} if this key is derived from another key and so should not be listed

     */

    String getDocName();

    /**

     * Gets the documentation for this key.

     *

     * @return {@code null} if this key has no documentation

     */

    String getDoc();

}