X-Git-Url: https://gerrit.onap.org/r/gitweb?a=blobdiff_plain;f=cadi%2Fcore%2Fsrc%2Fmain%2Fjava%2Forg%2Fonap%2Faaf%2Fcadi%2Futil%2FPool.java;h=6980e0aad44dfafb768711f1aad9cea905dc8ca9;hb=ea095eb9cdbb451f2310a262f3877c79f527cc8f;hp=156397b60feb2e4a943ed97d89927a122fffac9e;hpb=4b5a7d721d994a49057e9bfb403c7bff1b376660;p=aaf%2Fauthz.git diff --git a/cadi/core/src/main/java/org/onap/aaf/cadi/util/Pool.java b/cadi/core/src/main/java/org/onap/aaf/cadi/util/Pool.java index 156397b6..6980e0aa 100644 --- a/cadi/core/src/main/java/org/onap/aaf/cadi/util/Pool.java +++ b/cadi/core/src/main/java/org/onap/aaf/cadi/util/Pool.java @@ -7,9 +7,9 @@ * 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. @@ -21,7 +21,7 @@ /* * Pool - * + * * Author: Jonathan * 5/27/2011 */ @@ -35,29 +35,29 @@ import org.onap.aaf.cadi.CadiException; /** * This Class pools on an As-Needed-Basis any particular kind of class, which is * quite suitable for expensive operations. - * + * * The user calls "get" on a Pool, and if a waiting resource (T) is available, * it will be returned. Otherwise, one will be created with the "Creator" class * (must be defined for (T)). - * + * * You can Prime the instances to avoid huge startup costs - * + * * The returned "Pooled" object simply has to call "done()" and the object is * returned to the pool. If the developer does not return the object, a memory * leak does not occur. There are no references to the object once "get" is * called. However, the developer who does not return the object when done * obviates the point of the pool, as new Objects are created in place of the * Object not returned when another call to "get" is made. - * + * * There is a cushion of extra objects, currently defaulted to MAX_RANGE. If the * items returned become higher than the MAX_RANGE, the object is allowed to go * out of scope, and be cleaned up. the default can be changed on a per-pool * basis. - * + * * Class revamped for CadiExceptions and Access logging 10/4/2017 - * + * * @author Jonathan - * + * * @param */ public class Pool { @@ -65,32 +65,46 @@ public class Pool { * This is a constant which specified the default maximum number of unused * objects to be held at any given time. */ - private static final int MAX_RANGE = 6; // safety + public static final int MAX_RANGE = 6; // safety + + /** + * Maximum objects, in use or waiting + */ + public static final int MAX_OBJECTS = 20; // assumption for thread /** * only Simple List needed. - * + * * NOTE TO MAINTAINERS: THIS OBJECT DOES IT'S OWN SYNCHRONIZATION. All * changes that touch list must account for correctly synchronizing list. */ private LinkedList> list; /** - * keep track of how many elements exist, to avoid asking list. + * keep track of how many elements are currently available to use, to avoid asking list. */ private int count; - + /** - * Spares are those Object that are primed and ready to go. + * how many objects have been asked for, but not returned or tossed */ - private int spares; - + private int used; + /** * Actual MAX number of spares allowed to hang around. Can be set to * something besides the default MAX_RANGE. */ private int max_range = MAX_RANGE; + /** + * Actual MAX number of Objects both in use, or waiting. + * This does not actually affect the Pool, because the objects, once they leave the pool, are not known until + * they are put back with done (offer). It only affects the "overLimit()" function. + * + * Important... this information is only valid if PooledObjects call "done()" or "toss()". + */ + private int max_objects = MAX_OBJECTS; + /** * The Creator for this particular pool. It must work for type T. */ @@ -101,45 +115,60 @@ public class Pool { /** * Create a new Pool, given the implementation of Creator, which must be * able to create/destroy T objects at will. - * + * * @param creator */ public Pool(Creator creator) { - count = spares = 0; + count = used = 0; this.creator = creator; list = new LinkedList<>(); logger = Log.NULL; } - + /** * Attach Pool Logging activities to any other Logging Mechanism. * @param logger */ public void setLogger(Log logger) { this.logger = logger; + // Also reset existing Pooled objects + for(Pooled p : list) { + if(p.content instanceof LogAware) { + ((LogAware)p.content).setLog(logger); + } else { + break; + } + } } - - public void log(Object ...objects) { - logger.log(objects); + + public void log(Log.Type type, Object ...objects) { + logger.log(type,objects); } /** * Preallocate a certain number of T Objects. Useful for services so that * the first transactions don't get hit with all the Object creation costs * + * It is assumed that priming also means that it is the minimum desired available resources. Therefore, + * max_range is set to prime, if less than current max_range, if it is default. + * * @param lt * @param prime - * @throws CadiException + * @throws CadiException */ - public void prime(int prime) throws CadiException { + public Pool prime(int prime) throws CadiException { + if(max_range == MAX_RANGE && prime pt = new Pooled(creator.create(), this); synchronized (list) { list.addFirst(pt); ++count; + ++used; } } - + return this; } /** @@ -147,33 +176,36 @@ public class Pool { * down all Allocated objects cleanly for exiting. It is also a good method * for removing objects when, for instance, all Objects are invalid because * of broken connections, etc. + * + * Use in conjunction with setMaxRange to no longer store objects, i.e. + * + * pool.setMaxRange(0).drain(); */ - public void drain() { - synchronized (list) { - for (int i = 0; i < list.size(); ++i) { - Pooled pt = list.remove(); - creator.destroy(pt.content); - logger.log("Pool drained ", creator.toString()); - } - count = spares = 0; - } - + public synchronized void drain() { + while(list.size()>0) { + Pooled pt = list.remove(); + --used; + String name = pt.content.toString(); + creator.destroy(pt.content); + logger.log(Log.Type.debug,"Pool destroyed", name); + } + count = 0; } - + /** * This is the essential function for Pool. Get an Object "T" inside a * "Pooled" object. If there is a spare Object, then use it. If not, then * create and pass back. - * + * * This one uses a Null LogTarget - * + * * IMPORTANT: When the use of this object is done (and the object is still * in a valid state), then "done()" should be called immediately to allow * the object to be reused. That is the point of the Pool... - * + * * If the Object is in an invalid state, then "toss()" should be used so the * Pool doesn't pass on invalid objects to others. - * + * * @param lt * @return * @throws CadiException @@ -181,21 +213,14 @@ public class Pool { public Pooled get() throws CadiException { Pooled pt; synchronized (list) { - if (list.isEmpty()) { - pt = null; - } else { - pt = list.removeLast(); - --count; - creator.reuse(pt.content); - } + pt = list.pollLast(); } if (pt == null) { - if (spares < max_range) - ++spares; pt = new Pooled(creator.create(), this); + ++used; } else { - if (spares > 1) - --spares; + --count; + creator.reuse(pt.content); } return pt; } @@ -205,7 +230,7 @@ public class Pool { * state. If not, they are tossed from the Pool. This is valuable to have * when Remote Connections go down, and there is a question on whether the * Pooled Objects are still functional. - * + * * @return */ public boolean validate() { @@ -225,37 +250,49 @@ public class Pool { /** * This is an internal method, used only by the Internal Pooled class. - * + * * The Pooled class "offers" it's Object back after use. It is an * "offer", because Pool will simply destroy and remove the object if it has * more than enough spares. - * + * * @param lt * @param used * @return */ // Used only by Pooled - private boolean offer(Pooled used) { - if (count < spares) { + private boolean offer(Pooled usedP) { + if (count < max_range) { synchronized (list) { - list.addFirst(used); + list.addFirst(usedP); ++count; } - logger.log("Pool recovered ", creator); + logger.log(Log.Type.trace,"Pool recovered ", creator); } else { - logger.log("Pool destroyed ", creator); - creator.destroy(used.content); + destroy(usedP.content); } return false; } + + /** + * Destroy, using Creator's specific semantics, the Object, and decrement "used" + * + * @param t + */ + private void destroy(T t) { + creator.destroy(t); + synchronized (list) { + --used; + } + logger.log(Log.Type.debug,"Pool destroyed ", creator); + } /** * The Creator Interface give the Pool the ability to Create, Destroy and * Validate the Objects it is maintaining. Thus, it is a specially written * Implementation for each type. - * + * * @author Jonathan - * + * * @param */ public interface Creator { @@ -268,20 +305,22 @@ public class Pool { public void reuse(T t); } - public interface Log { - public void log(Object ... o); - - public final static Log NULL = new Log() { - @Override - public void log(Object ... o) { - } - }; + /** + * Pooled Classes can be "Log Aware", which means they can tie into the same + * Logging element that the Pool is using. To do this, the Object must implement "LogAware" + * + * @author Jonathan + * + */ + public interface LogAware { + public void setLog(Log log); } + /** * The "Pooled" class is the transient class that wraps the actual Object * T for API use/ It gives the ability to return ("done()", or "toss()") the * Object to the Pool when processing is finished. - * + * * For Safety, i.e. to avoid memory leaks and invalid Object States, there * is a "finalize" method. It is strictly for when coder forgets to return * the object, or perhaps hasn't covered the case during Exceptions or @@ -291,9 +330,9 @@ public class Pool { * However, we don't want Coding Mistakes to put the whole program in an * invalid state, so if something happened such that "done()" or "toss()" * were not called, the resource is still cleaned up as well as possible. - * + * * @author Jonathan - * + * * @param */ public static class Pooled { @@ -302,21 +341,23 @@ public class Pool { /** * Create the Wrapping Object Pooled. - * + * * @param t * @param pool * @param logTarget */ public Pooled(T t, Pool pool) { content = t; + if(t instanceof LogAware) { + ((LogAware)t).setLog(pool.logger); + } this.pool = pool; - } /** * This is the key API for the Pool, as calling "done()" offers this * object back to the Pool for reuse. - * + * * Do not use the Pooled object again after calling "done()". */ public void done() { @@ -329,16 +370,16 @@ public class Pool { * The user of the Object may discover that the Object t is no longer in * a valid state. Don't put Garbage back in the Refrigerator... Toss it, * if it's no longer valid. - * + * * toss() is also used for draining the Pool, etc. - * + * * toss() will attempt to destroy the Object by using the Creator * Interface. - * + * */ public void toss() { if (pool != null) { - pool.creator.destroy(content); + pool.destroy(content); } // Don't allow finalize to put it back in. pool = null; @@ -356,27 +397,57 @@ public class Pool { pool = null; } } + + @Override + public String toString() { + return content.toString(); + } } /** - * Get the maximum number of spare objects allowed at any moment + * Set a Max Range for numbers of spare objects waiting to be used. + * + * No negative numbers are allowed * + * Use in conjunction with drain to no longer store objects, i.e. + * + * pool.setMaxRange(0).drain(); + * * @return */ - public int getMaxRange() { - return max_range; + public Pool setMaxRange(int max_range) { + // Do not allow negative numbers + this.max_range = Math.max(0, max_range); + return this; } - + /** * Set a Max Range for numbers of spare objects waiting to be used. - * + * * No negative numbers are allowed - * + * * @return */ - public void setMaxRange(int max_range) { + public Pool setMaxObjects(int max_objects) { // Do not allow negative numbers - this.max_range = Math.max(0, max_range); + this.max_objects = Math.max(0, max_objects); + return this; } + /** + * return whether objects in use or waiting are beyond max allowed + * + * Pool does not actually stop new creations, but allows this to be used by + * other entities to limit number of creations of expensive Objects, like + * Thread Pooling + * + */ + public boolean tooManyObjects() { + return used > max_objects; + } + + public String toString() { + return String.format("Pool: count(%d), used(%d), max_range(%d), max_objects(%d)", + count, used,max_range,max_objects); + } }