activemq-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From michaelandrepearce <...@git.apache.org>
Subject [GitHub] activemq-artemis pull request #2490: V2 196
Date Wed, 09 Jan 2019 22:43:35 GMT
Github user michaelandrepearce commented on a diff in the pull request:

    https://github.com/apache/activemq-artemis/pull/2490#discussion_r246574781
  
    --- Diff: artemis-commons/src/main/java/org/apache/activemq/artemis/utils/collections/PriorityCollection.java
---
    @@ -0,0 +1,319 @@
    +/*
    + * Licensed to the Apache Software Foundation (ASF) under one or more
    + * contributor license agreements. See the NOTICE file distributed with
    + * this work for additional information regarding copyright ownership.
    + * The ASF licenses this file to You 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.
    + */
    +package org.apache.activemq.artemis.utils.collections;
    +
    +import org.apache.activemq.artemis.core.PriorityAware;
    +
    +import java.lang.reflect.Array;
    +import java.util.AbstractCollection;
    +import java.util.Arrays;
    +import java.util.Collection;
    +import java.util.Iterator;
    +import java.util.Objects;
    +import java.util.Set;
    +import java.util.function.Consumer;
    +import java.util.function.Supplier;
    +import java.util.stream.Collectors;
    +
    +/**
    + * This class's purpose is to hold the the different collections used for each priority
level.
    + *
    + * A supplier is required to provide the underlying collection needed when a new priority
level is seen,
    + * and the end behaviour is that of the underlying collection, e.g. if set add will follow
set's add semantics,
    + * if list, then list semantics.
    + *
    + * Methods getArray, setArray MUST never be exposed, and all array modifications must
go through these.
    + *
    + * @param <T> The type this class may hold, this is generic as can be anything
that extends PriorityAware.
    + */
    +public class PriorityCollection<T extends PriorityAware> extends AbstractCollection<T>
{
    +
    +   private final Supplier<Collection<T>> supplier;
    +   private volatile PriorityHolder<T>[] priorityHolders = newPrioritySetArrayInstance(0);
    +   private volatile int size;
    +
    +   private void setArray(PriorityHolder<T>[] priorityHolders) {
    +      this.priorityHolders = priorityHolders;
    +   }
    +
    +   private PriorityHolder<T>[] getArray() {
    +      return priorityHolders;
    +   }
    +
    +
    +   public PriorityCollection(Supplier<Collection<T>> supplier) {
    +      this.supplier = supplier;
    +   }
    +
    +   @SuppressWarnings("unchecked")
    +   private static <T> PriorityHolder<T>[] newPrioritySetArrayInstance(int
length) {
    +      return (PriorityHolder<T>[]) Array.newInstance(PriorityHolder.class, length);
    +   }
    +
    +   @Override
    +   public int size() {
    +      return size;
    +   }
    +
    +   @Override
    +   public boolean isEmpty() {
    +      return size() == 0;
    +   }
    +
    +   public Set<Integer> getPriorites() {
    +      PriorityHolder<T>[] snapshot = getArray();
    +      return Arrays.stream(snapshot).map(PriorityAware::getPriority).collect(Collectors.toSet());
    +   }
    +
    +   @Override
    +   public Iterator<T> iterator() {
    +      Iterator<T>[] iterators = getIterators();
    +      return new MultiIterator<>(iterators);
    +   }
    +
    +   private Iterator<T>[] getIterators() {
    +      PriorityHolder<T>[] snapshot = this.getArray();
    +      int size = snapshot.length;
    +      Iterator<T>[] iterators = newIteratorArrayInstance(size);
    +      for (int i = 0; i < size; i++) {
    +         iterators[i] = snapshot[i].getValues().iterator();
    +      }
    +      return iterators;
    +   }
    +
    +   @SuppressWarnings("unchecked")
    +   private static <T> Iterator<T>[] newIteratorArrayInstance(int length)
{
    +      return (Iterator<T>[]) Array.newInstance(Iterator.class, length);
    +   }
    +
    +   public ResettableIterator<T> resettableIterator() {
    +      return new MultiResettableIterator<T>(getResettableIterators());
    +   }
    +
    +   private ResettableIterator<T>[] getResettableIterators() {
    +      PriorityHolder<T>[] snapshot = this.getArray();
    +      int size = snapshot.length;
    +      ResettableIterator<T>[] iterators = newResettableIteratorArrayInstance(size);
    +      for (int i = 0; i < size; i++) {
    +         iterators[i] = new ArrayResettableIterator<>(snapshot[i].getValues().toArray());
    +      }
    +      return iterators;
    +   }
    +
    +   @SuppressWarnings("unchecked")
    +   private static <T> ResettableIterator<T>[] newResettableIteratorArrayInstance(int
length) {
    +      return (ResettableIterator<T>[]) Array.newInstance(ResettableIterator.class,
length);
    +   }
    +
    +   @Override
    +   public void forEach(Consumer<? super T> action) {
    +      Objects.requireNonNull(action);
    +      PriorityHolder<T>[] current = getArray();
    +      int len = current.length;
    +      for (int i = 0; i < len; ++i) {
    +         current[i].getValues().forEach(action);
    +      }
    +   }
    +
    +   private Collection<T> getCollection(int priority, boolean createIfMissing) {
    +      PriorityHolder<T>[] current = getArray();
    +      int low = 0;
    +      int high = current.length - 1;
    +
    +      while (low <= high) {
    +         int mid = (low + high) >>> 1;
    +         PriorityHolder<T> midVal = current[mid];
    +
    +         if (midVal.getPriority() > priority)
    +            low = mid + 1;
    +         else if (midVal.getPriority() < priority)
    +            high = mid - 1;
    +         else
    +            return midVal.getValues(); //key found
    +      }
    +
    +      if (createIfMissing) {
    +         PriorityHolder<T>[] newArray = newPrioritySetArrayInstance(current.length
+ 1);
    +         if (low > 0) {
    +            System.arraycopy(current, 0, newArray, 0, low);
    +         }
    +         if (current.length - low > 0) {
    +            System.arraycopy(current, low, newArray, low + 1, current.length - low);
    +         }
    +         newArray[low] = new PriorityHolder<T>(priority, supplier);
    +         setArray(newArray);
    +         return newArray[low].getValues();
    +      }
    +      return null;
    +   }
    +
    +   @Override
    +   public synchronized boolean add(T t) {
    +      boolean result = addInternal(t);
    +      calcSize();
    +      return result;
    +   }
    +
    +   private boolean addInternal(T t) {
    +      if (t == null) return false;
    +      Collection<T> priority = getCollection(t.getPriority(), true);
    +      return priority.add(t);
    +   }
    +
    +   @Override
    +   public boolean remove(Object o) {
    +      return o instanceof PriorityAware && remove((PriorityAware) o);
    +   }
    +
    +   public synchronized boolean remove(PriorityAware priorityAware) {
    +      boolean result = removeInternal(priorityAware);
    +      calcSize();
    +      return result;
    +   }
    +
    +   private boolean removeInternal(PriorityAware priorityAware) {
    +      if ( priorityAware == null) return false;
    +      Collection<T> priority = getCollection(priorityAware.getPriority(), false);
    +      boolean result = priority != null && priority.remove(priorityAware);
    +      if (priority != null && priority.size() == 0) {
    +         removeCollection(priorityAware.getPriority());
    +      }
    +      return result;
    +   }
    +
    +   private Collection<T> removeCollection(int priority) {
    +      PriorityHolder<T>[] current = getArray();
    +      int len = current.length;
    +      int low = 0;
    +      int high = len - 1;
    +
    +      while (low <= high) {
    +         int mid = (low + high) >>> 1;
    --- End diff --
    
    still just a coding preference, i see you even do bitwise alot when can be just written
in standard math ;) ..... 
    
    anyhow have changed to avoid disagreement.


---

Mime
View raw message