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 * Copyright (c) 2013, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.jersey.server.monitoring;

import java.util.Date;
import java.util.Map;

Monitoring statistics of execution of one target. ExecutionStatistics contains TimeWindowStatistics for various time window sizes. 
 Statistics retrieved from Jersey runtime might be mutable and thanks to it might provide inconsistent data as not all statistics are updated in the same time. To retrieve the immutable and consistent statistics data the method snapshot() should be used. 
Author:
Miroslav Fuksa
See Also:
See monitoring statistics for general details about statistics./**
 * Monitoring statistics of execution of one target. {@code ExecutionStatistics} contains
 * {@link TimeWindowStatistics} for various time window sizes.
 * <p/>
 * Statistics retrieved from Jersey runtime might be mutable and thanks to it might provide inconsistent data
 * as not all statistics are updated in the same time. To retrieve the immutable and consistent
 * statistics data the method {@link #snapshot()} should be used.
 *
 * @author Miroslav Fuksa
 * @see MonitoringStatistics See monitoring statistics for general details about statistics.
 */
public interface ExecutionStatistics {

    
Return time when target was executed last time. The time is measured before the target was executed.
Returns:
Time of last execution./**
     * Return time when target was executed last time. The time is measured before the target was executed.
     *
     * @return Time of last execution.
     */
    public Date getLastStartTime();

    
Returns time window statistics for available time window sizes. The returned map contains sizes of a time window in milliseconds as keys and time window statistics for the corresponding time window as value. 
Returns:
Map with size of a time window in milliseconds as keys and time window statistics for the corresponding time window as value./**
     * Returns time window statistics for available time window sizes. The returned map contains sizes
     * of a time window in milliseconds as keys and
     * {@link TimeWindowStatistics time window statistics} for the corresponding time window
     * as value.
     *
     * @return Map with size of a time window in milliseconds as keys and
     *         {@link TimeWindowStatistics time window statistics} for the corresponding time window
     *         as value.
     */
    public Map<Long, TimeWindowStatistics> getTimeWindowStatistics();

    
Get the immutable consistent snapshot of the monitoring statistics. Working with snapshots might
have negative performance impact as snapshot must be created but ensures consistency of data over time.
However, the usage of snapshot is encouraged to avoid working with inconsistent data. Not all statistics
must be updated in the same time on mutable version of statistics.
Returns:
Snapshot of execution statistics.
Deprecated:
implementing class is immutable hence snapshot creation is not needed anymore/**
     * Get the immutable consistent snapshot of the monitoring statistics. Working with snapshots might
     * have negative performance impact as snapshot must be created but ensures consistency of data over time.
     * However, the usage of snapshot is encouraged to avoid working with inconsistent data. Not all statistics
     * must be updated in the same time on mutable version of statistics.
     *
     * @return Snapshot of execution statistics.
     * @deprecated implementing class is immutable hence snapshot creation is not needed anymore
     */
    @Deprecated
    public ExecutionStatistics snapshot();
}