P2JQueryStatistics.java
/*
** Module : P2JQueryStatistics.java
** Abstract : Manages statistics for P2J queries
**
** Copyright (c) 2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 RAA 20230522 First revision with basic usage.
** 002 RAA 20230802 Introduced two maps to store overall statistics.
** RAA 20231122 Removed location and fql fields from main class. Refactored gatherQueryDetails to use
** indexed looping. Pre-computed hashCode for both subclasses.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
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**
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*/
package com.goldencode.p2j.persist;
import java.util.*;
/**
* Class responsible with storing information about P2J Queries.
* For the moment, only {@link CompoundQuery} and {@link RandomAccessQuery} support this type
* of storing statistics.
*/
public class P2JQueryStatistics
{
/** Transient map of query instances to information about where they were constructed. */
private static final Map<Key, P2JQueryStatistics> statistics = new LinkedHashMap<>();
/** Map that stores the location of queries. */
private static final Map<P2JQuery, Location> locations = new WeakHashMap<>();
/** Number of times query was executed at this location (across query instances). */
private long useCount = 0;
/** The execution time of this query until this moment. */
private double time = 0;
/**
* Default constructor.
*/
private P2JQueryStatistics()
{
}
/**
* Function that retrieves/creates the statistics of a query.
*
* @param query
* The query in use.
* @param fql
* The FQL of the query.
*
* @return P2JQueryStatistics
* An instance of {@code P2JQueryStatistics} denoting the statistics of the given query.
*/
public static P2JQueryStatistics getStatistics(P2JQuery query, String fql)
{
// First find/create the location of the query
Location location = null;
synchronized (locations)
{
location = locations.get(query);
}
if (location == null)
{
location = gatherQueryDetails();
synchronized (locations)
{
locations.put(query, location);
}
}
// Then access its statistics
Key key = new Key(location, fql);
P2JQueryStatistics info = null;
synchronized (statistics)
{
info = statistics.get(key);
}
if (info == null)
{
info = new P2JQueryStatistics();
synchronized (statistics)
{
statistics.put(key, info);
}
}
return info;
}
/**
* Function that returns the location of a query (if one exists), in a ready to be printed format.
*
* @param query
* The given query.
*
* @return String
* The formatted string that denotes the location of the query, or {@code null} if no such
* location exists.
*/
public static String getLocationFormattedOutput(P2JQuery query)
{
Location location = null;
synchronized (locations)
{
location = locations.get(query);
}
return location == null ? null : location.toString();
}
/**
* Get the number of times the FQL query was executed at this location, across all query
* instances constructed at the same location.
*
* @return long
* Query execution count.
*/
public long getUseCount()
{
return useCount;
}
/**
* Increment by one the number of times the FQL query was executed at this location, across
* all query instances constructed at the same location.
*/
public void incrementUseCount()
{
useCount++;
}
/**
* Getter for the {@code time} field.
*
* @return double
* The execution time of the query until this moment.
*/
public double getTime()
{
return time;
}
/**
* Method for increasing the total time of this query by a specified amount.
*
* @param time
* The time that will be added to the total time.
*/
public void increaseTime(double time)
{
this.time += time;
}
/**
* Function that navigates the stack trace, identifies details of a query (such as file name, method name,
* line number) and creates a {@code Location} based on those findings.
*
* @return Location
* The location of a query.
*/
private static Location gatherQueryDetails()
{
Throwable t = new Throwable();
String queryClass = null;
String fileName = null;
String methodName = null;
String className = null;
int lineNumber = -1;
String previousFileName = null;
String previousMethodName = null;
String previousClassName = null;
int previousLineNumber = -1;
StackTraceElement[] stackTraceElements = t.getStackTrace();
for (int i = 0; i < stackTraceElements.length; i++)
{
className = stackTraceElements[i].getClassName();
fileName = stackTraceElements[i].getFileName();
lineNumber = stackTraceElements[i].getLineNumber();
methodName = stackTraceElements[i].getMethodName();
if (queryClass != null && !fileName.equals(queryClass))
{
return new Location(previousFileName, previousLineNumber, previousClassName, previousMethodName);
}
else if (queryClass == null && className.lastIndexOf('$') < 0 && !fileName.startsWith("P2JQuery"))
{
queryClass = fileName;
}
previousClassName = className;
previousFileName = fileName;
previousLineNumber = lineNumber;
previousMethodName = methodName;
}
return null;
}
/**
* Helper class which stores location information regarding the construction of a P2J query.
*/
private static class Location
{
/** Unqualified application source code file name containing query. */
private final String sourceFile;
/** Line number at which query was constructed. */
private final int lineNumber;
/** Name of application class (sans package root name) containing query. */
private final String className;
/** Name of application-level method in which query was executed. */
private final String methodName;
/** The hash code of this {@code Location}. */
private final int hashCode;
/**
* Constructor.
*
* @param sourceFile
* Unqualified application source code file name containing query.
* @param lineNumber
* Line number at which query was constructed.
* @param className
* Name of application class (sans package root name) containing query.
* @param methodName
* Name of application-level method in which query was executed
*/
private Location(String sourceFile, int lineNumber, String className, String methodName)
{
this.sourceFile = sourceFile.intern();
this.lineNumber = lineNumber;
this.className = className.intern();
this.methodName = methodName.intern();
hashCode = 37 *
(37 *
(37 *
(37 * 17 + lineNumber)
+ className.hashCode())
+ methodName.hashCode())
+ sourceFile.hashCode();
}
/**
* Return the hash code computed for this object instance.
*
* @return int
* Hash code.
*/
@Override
public int hashCode()
{
return hashCode;
}
/**
* Indicate whether this object instance is equivalent to the given instance, based on
* the content of both.
*
* @return boolean
* {@code true} if equivalent, {@code false} otherwise.
*/
@Override
public boolean equals(Object o)
{
if (!(o instanceof Location))
{
return false;
}
Location that = (Location) o;
return this.lineNumber == that.lineNumber &&
this.className == that.className &&
this.methodName == that.methodName &&
this.sourceFile == that.sourceFile;
}
/**
* A formatted way of presenting a {@code Location}.
*
* @return String
* The {@code String} representing the {@code Location}.
*/
@Override
public String toString()
{
StringBuilder result = new StringBuilder();
result.append("Source file: ").append(sourceFile)
.append("; Method name: ").append(methodName)
.append("; Line number: ").append(lineNumber);
return result.toString();
}
}
/**
* A hashable key comprised of both location information and an FQL string. Location info
* alone is not enough to differentiate queries, because different FQL can be executed
* from a query constructed at the same code location.
*/
private static class Key
{
/** Query construction location information. */
private final Location location;
/** Dialect-specific FQL query string. */
private final String fql;
/** The hash code of this {@code Key}. */
private final int hashCode;
/**
* Constructor.
*
* @param location
* Query construction location information.
* @param fql
* Dialect-specific FQL query string.
*/
Key(Location location, String fql)
{
this.location = location;
this.fql = fql;
hashCode = 37 * (37 * 17 + location.hashCode()) + fql.hashCode();
}
/**
* Return the hash code computed for this object instance.
*
* @return int
* Hash code.
*/
public int hashCode()
{
return hashCode;
}
/**
* Indicate whether this object instance is equivalent to the given instance, based on
* the content of both.
*
* @return boolean
* {@code true} if equivalent, {@code false} otherwise.
*/
public boolean equals(Object o)
{
if (!(o instanceof Key))
{
return false;
}
Key that = (Key) o;
return (this.fql.equals(that.fql) && this.location.equals(that.location));
}
}
}