/**
 * ============LICENSE_START====================================================
 * org.onap.aaf
 * ===========================================================================
 * Copyright (c) 2018 AT&T Intellectual Property. All rights reserved.
 * ===========================================================================
 * 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.
 * ============LICENSE_END====================================================
 *
 */

package org.onap.aaf.misc.env;

/**
 * <h1>TimeTaken</h1>
 * This simple interface allows for many different kinds of 
 * Audit Logs to be accomplished, by assuming that the creation
 * of this object indicates "start", and the calling of "done" 
 * ends.
 * 
 * The implementor of this class can easily be stored in efficient
 * mechanisms to minimize impact of Auditing on performance.
 * 
 * @author Jonathan
 *
 */
public abstract class TimeTaken {
    public final long start;
    protected long end, size;
    public final int flag;
    public final String name;
    public final Object[] values;
    
    /**
     * The name is as it will appear when written to output (abstract method)
     * 
     * The flag is an integer which can be System type (XML, REMOTE, etc), or End User defined for reporting purposes 
     * 
     * @param name
     * @param flag
     * @param values 
     */
    public TimeTaken(String name, int flag, Object ... values) {
        start = System.nanoTime();
        this.flag = flag;
        this.name = name;
        this.values = values;
        size = -1;
    }


     /**
     * Call this when process is done to state ending time.<p>
     * 
     * It is <i>exceedingly prudent</i> to wrap the process called with a try-finally:<p>
     * 
     * <pre>
     *   TimeTaken tt = env.startSubTime();
     *   try {
     *       process.me(); // code to be timed.
     *   } finally {
     *        tt.done();
     *   }
     * </pre>
     */
    public void done() {
        end = System.nanoTime();
    }
    

    /**
     * For sizable contents, set the size.  Implementations can simply write a no-op if they don't wish to 
     * store the size. 
     * 
     * @param size
     */
    public void size(long theSize) {
        size = theSize;
    }
    
    /**
     * Give readonly access to End, which isn't final
     * @return
     */
    public long end() {
        return end;
    }
    
    /**
     * Time is taken in NanoSeconds.  This method converts to decimals of Milliseconds
     * @return
     */
    public float millis() {
        return (end-start)/1000000f;
    }
    /**
     * Write self to a String Builder (for making Audits)
     * @param sb
     */
    public abstract void output(StringBuilder sb);
    
    /**
     * For Debugging
     */
    public String toString() {
        return name + ' ' + millis() + "ms " + (size>0?Long.toString(size):"");
    }
    
}