docs/attachments/LUCENE-6095/LUCENE-6095.patch

Index: lucene/core/src/test/org/apache/lucene/util/TestIdentityHashSet.java
===================================================================
--- lucene/core/src/test/org/apache/lucene/util/TestIdentityHashSet.java	(revision 1643373)
+++ lucene/core/src/test/org/apache/lucene/util/TestIdentityHashSet.java	(working copy)
@@ -1,56 +0,0 @@
-package org.apache.lucene.util;
-
-/*
- * 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.
- */
-
-import java.util.*;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-public class TestIdentityHashSet extends LuceneTestCase {
-  @Test
-  public void testCheck() {
-    Random rnd = random();
-    Set<Object> jdk = Collections.newSetFromMap(
-        new IdentityHashMap<Object,Boolean>());
-    RamUsageTester.IdentityHashSet<Object> us = new RamUsageTester.IdentityHashSet<>();
-
-    int max = 100000;
-    int threshold = 256;
-    for (int i = 0; i < max; i++) {
-      // some of these will be interned and some will not so there will be collisions.
-      Integer v = rnd.nextInt(threshold);
-      
-      boolean e1 = jdk.contains(v);
-      boolean e2 = us.contains(v);
-      Assert.assertEquals(e1, e2);
-
-      e1 = jdk.add(v);
-      e2 = us.add(v);
-      Assert.assertEquals(e1, e2);
-    }
-    
-    Set<Object> collected = Collections.newSetFromMap(
-        new IdentityHashMap<Object,Boolean>());
-    for (Object o : us) {
-      collected.add(o);
-    }
-    
-    Assert.assertEquals(collected, jdk);
-  }
-}
Index: lucene/test-framework/src/java/org/apache/lucene/util/RamUsageTester.java
===================================================================
--- lucene/test-framework/src/java/org/apache/lucene/util/RamUsageTester.java	(revision 1643373)
+++ lucene/test-framework/src/java/org/apache/lucene/util/RamUsageTester.java	(working copy)
@@ -22,15 +22,13 @@
 import java.lang.reflect.Modifier;
 import java.util.AbstractList;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.IdentityHashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
-import java.util.NoSuchElementException;
+import java.util.Set;
 
 /** Crawls object graph to collect RAM usage for testing */
 public final class RamUsageTester {
@@ -91,7 +89,7 @@
    */
   private static long measureObjectSize(Object root, Accumulator accumulator) {
     // Objects seen so far.
-    final IdentityHashSet<Object> seen = new IdentityHashSet<>();
+    final Set<Object> seen = Collections.newSetFromMap(new IdentityHashMap<Object, Boolean>());
     // Class cache with reference Field and precalculated shallow size. 
     final IdentityHashMap<Class<?>, ClassCache> classCache = new IdentityHashMap<>();
     // Stack of objects pending traversal. Recursion caused stack overflows. 
@@ -213,243 +211,5 @@
         referenceFields.toArray(new Field[referenceFields.size()]));
     return cachedInfo;
   }
-  
-  /**
-   * An identity hash set implemented using open addressing. No null keys are allowed.
-   * 
-   * TODO: If this is useful outside this class, make it public - needs some work
-   */
-  static final class IdentityHashSet<KType> implements Iterable<KType> {
-    /**
-     * Default load factor.
-     */
-    public final static float DEFAULT_LOAD_FACTOR = 0.75f;
 
-    /**
-     * Minimum capacity for the set.
-     */
-    public final static int MIN_CAPACITY = 4;
-
-    /**
-     * All of set entries. Always of power of two length.
-     */
-    public Object[] keys;
-    
-    /**
-     * Cached number of assigned slots.
-     */
-    public int assigned;
-    
-    /**
-     * The load factor for this set (fraction of allocated or deleted slots before
-     * the buffers must be rehashed or reallocated).
-     */
-    public final float loadFactor;
-    
-    /**
-     * Cached capacity threshold at which we must resize the buffers.
-     */
-    private int resizeThreshold;
-    
-    /**
-     * Creates a hash set with the default capacity of 16.
-     * load factor of {@value #DEFAULT_LOAD_FACTOR}. `
-     */
-    public IdentityHashSet() {
-      this(16, DEFAULT_LOAD_FACTOR);
-    }
-    
-    /**
-     * Creates a hash set with the given capacity, load factor of
-     * {@value #DEFAULT_LOAD_FACTOR}.
-     */
-    public IdentityHashSet(int initialCapacity) {
-      this(initialCapacity, DEFAULT_LOAD_FACTOR);
-    }
-    
-    /**
-     * Creates a hash set with the given capacity and load factor.
-     */
-    public IdentityHashSet(int initialCapacity, float loadFactor) {
-      initialCapacity = Math.max(MIN_CAPACITY, initialCapacity);
-      
-      assert initialCapacity > 0 : "Initial capacity must be between (0, "
-          + Integer.MAX_VALUE + "].";
-      assert loadFactor > 0 && loadFactor < 1 : "Load factor must be between (0, 1).";
-      this.loadFactor = loadFactor;
-      allocateBuffers(roundCapacity(initialCapacity));
-    }
-    
-    /**
-     * Adds a reference to the set. Null keys are not allowed.
-     */
-    public boolean add(KType e) {
-      assert e != null : "Null keys not allowed.";
-      
-      if (assigned >= resizeThreshold) expandAndRehash();
-      
-      final int mask = keys.length - 1;
-      int slot = rehash(e) & mask;
-      Object existing;
-      while ((existing = keys[slot]) != null) {
-        if (e == existing) {
-          return false; // already found.
-        }
-        slot = (slot + 1) & mask;
-      }
-      assigned++;
-      keys[slot] = e;
-      return true;
-    }
-
-    /**
-     * Checks if the set contains a given ref.
-     */
-    public boolean contains(KType e) {
-      final int mask = keys.length - 1;
-      int slot = rehash(e) & mask;
-      Object existing;
-      while ((existing = keys[slot]) != null) {
-        if (e == existing) {
-          return true;
-        }
-        slot = (slot + 1) & mask;
-      }
-      return false;
-    }
-
-    /** Rehash via MurmurHash.
-     * 
-     * <p>The implementation is based on the
-     * finalization step from Austin Appleby's
-     * <code>MurmurHash3</code>.
-     * 
-     * @see <a href="http://sites.google.com/site/murmurhash/">http://sites.google.com/site/murmurhash/</a>
-     */
-    private static int rehash(Object o) {
-      int k = System.identityHashCode(o);
-      k ^= k >>> 16;
-      k *= 0x85ebca6b;
-      k ^= k >>> 13;
-      k *= 0xc2b2ae35;
-      k ^= k >>> 16;
-      return k;
-    }
-    
-    /**
-     * Expand the internal storage buffers (capacity) or rehash current keys and
-     * values if there are a lot of deleted slots.
-     */
-    private void expandAndRehash() {
-      final Object[] oldKeys = this.keys;
-      
-      assert assigned >= resizeThreshold;
-      allocateBuffers(nextCapacity(keys.length));
-      
-      /*
-       * Rehash all assigned slots from the old hash table.
-       */
-      final int mask = keys.length - 1;
-      for (int i = 0; i < oldKeys.length; i++) {
-        final Object key = oldKeys[i];
-        if (key != null) {
-          int slot = rehash(key) & mask;
-          while (keys[slot] != null) {
-            slot = (slot + 1) & mask;
-          }
-          keys[slot] = key;
-        }
-      }
-      Arrays.fill(oldKeys, null);
-    }
-    
-    /**
-     * Allocate internal buffers for a given capacity.
-     * 
-     * @param capacity
-     *          New capacity (must be a power of two).
-     */
-    private void allocateBuffers(int capacity) {
-      this.keys = new Object[capacity];
-      this.resizeThreshold = (int) (capacity * DEFAULT_LOAD_FACTOR);
-    }
-    
-    /**
-     * Return the next possible capacity, counting from the current buffers' size.
-     */
-    protected int nextCapacity(int current) {
-      assert current > 0 && Long.bitCount(current) == 1 : "Capacity must be a power of two.";
-      assert ((current << 1) > 0) : "Maximum capacity exceeded ("
-          + (0x80000000 >>> 1) + ").";
-      
-      if (current < MIN_CAPACITY / 2) current = MIN_CAPACITY / 2;
-      return current << 1;
-    }
-    
-    /**
-     * Round the capacity to the next allowed value.
-     */
-    protected int roundCapacity(int requestedCapacity) {
-      // Maximum positive integer that is a power of two.
-      if (requestedCapacity > (0x80000000 >>> 1)) return (0x80000000 >>> 1);
-      
-      int capacity = MIN_CAPACITY;
-      while (capacity < requestedCapacity) {
-        capacity <<= 1;
-      }
-
-      return capacity;
-    }
-    
-    public void clear() {
-      assigned = 0;
-      Arrays.fill(keys, null);
-    }
-    
-    public int size() {
-      return assigned;
-    }
-    
-    public boolean isEmpty() {
-      return size() == 0;
-    }
-
-    @Override
-    public Iterator<KType> iterator() {
-      return new Iterator<KType>() {
-        int pos = -1;
-        Object nextElement = fetchNext();
-
-        @Override
-        public boolean hasNext() {
-          return nextElement != null;
-        }
-
-        @SuppressWarnings("unchecked")
-        @Override
-        public KType next() {
-          Object r = this.nextElement;
-          if (r == null) {
-            throw new NoSuchElementException();
-          }
-          this.nextElement = fetchNext();
-          return (KType) r;
-        }
-
-        private Object fetchNext() {
-          pos++;
-          while (pos < keys.length && keys[pos] == null) {
-            pos++;
-          }
-
-          return (pos >= keys.length ? null : keys[pos]);
-        }
-
-        @Override
-        public void remove() {
-          throw new UnsupportedOperationException();
-        }
-      };
-    }
-  }
 }