X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/collections/ArrayHashMap.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/collections/ArrayHashMap.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/collections/ArrayHashMap.java
new file mode 100644
index 0000000..b2ff567
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/util/collections/ArrayHashMap.java
@@ -0,0 +1,546 @@
+package org.apache.lucene.util.collections;
+
+import java.util.Arrays;
+import java.util.Iterator;
+
+/**
+ * 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.
+ */
+
+/**
+ * An Array-based hashtable which maps, similar to Java's HashMap, only
+ * performance tests showed it performs better.
+ * <p>
+ * The hashtable is constructed with a given capacity, or 16 as a default. In
+ * case there's not enough room for new pairs, the hashtable grows. Capacity is
+ * adjusted to a power of 2, and there are 2 * capacity entries for the hash.
+ * The pre allocated arrays (for keys, values) are at length of capacity + 1,
+ * where index 0 is used as 'Ground' or 'NULL'.
+ * <p>
+ * The arrays are allocated ahead of hash operations, and form an 'empty space'
+ * list, to which the &lt;key,value&gt; pair is allocated.
+ * 
+ * @lucene.experimental
+ */
+public class ArrayHashMap<K,V> implements Iterable<V> {
+
+  /** Implements an IntIterator which iterates over all the allocated indexes. */
+  private final class IndexIterator implements IntIterator {
+    /**
+     * The last used baseHashIndex. Needed for "jumping" from one hash entry
+     * to another.
+     */
+    private int baseHashIndex = 0;
+
+    /** The next not-yet-visited index. */
+    private int index = 0;
+
+    /** Index of the last visited pair. Used in {@link #remove()}. */
+    private int lastIndex = 0;
+
+    /**
+     * Create the Iterator, make <code>index</code> point to the "first"
+     * index which is not empty. If such does not exist (eg. the map is
+     * empty) it would be zero.
+     */
+    public IndexIterator() {
+      for (baseHashIndex = 0; baseHashIndex < baseHash.length; ++baseHashIndex) {
+        index = baseHash[baseHashIndex];
+        if (index != 0) {
+          break;
+        }
+      }
+    }
+
+    public boolean hasNext() {
+      return index != 0;
+    }
+
+    public int next() {
+      // Save the last index visited
+      lastIndex = index;
+
+      // next the index
+      index = next[index];
+
+      // if the next index points to the 'Ground' it means we're done with
+      // the current hash entry and we need to jump to the next one. This
+      // is done until all the hash entries had been visited.
+      while (index == 0 && ++baseHashIndex < baseHash.length) {
+        index = baseHash[baseHashIndex];
+      }
+
+      return lastIndex;
+    }
+
+    @SuppressWarnings("unchecked")
+    public void remove() {
+      ArrayHashMap.this.remove((K) keys[lastIndex]);
+    }
+
+  }
+
+  /** Implements an Iterator, used for iteration over the map's keys. */
+  private final class KeyIterator implements Iterator<K> {
+    private IntIterator iterator = new IndexIterator();
+
+    KeyIterator() { }
+
+    public boolean hasNext() {
+      return iterator.hasNext();
+    }
+
+    @SuppressWarnings("unchecked")
+    public K next() {
+      return (K) keys[iterator.next()];
+    }
+
+    public void remove() {
+      iterator.remove();
+    }
+  }
+
+  /** Implements an Iterator, used for iteration over the map's values. */
+  private final class ValueIterator implements Iterator<V> {
+    private IntIterator iterator = new IndexIterator();
+
+    ValueIterator() { }
+
+    public boolean hasNext() {
+      return iterator.hasNext();
+    }
+
+    @SuppressWarnings("unchecked")
+    public V next() {
+      return (V) values[iterator.next()];
+    }
+
+    public void remove() {
+      iterator.remove();
+    }
+  }
+
+  /** Default capacity - in case no capacity was specified in the constructor */
+  private static final int DEFAULT_CAPACITY = 16;
+
+  /**
+   * Holds the base hash entries. if the capacity is 2^N, than the base hash
+   * holds 2^(N+1).
+   */
+  int[] baseHash;
+
+  /**
+   * The current capacity of the map. Always 2^N and never less than 16. We
+   * never use the zero index. It is needed to improve performance and is also
+   * used as "ground".
+   */
+  private int capacity;
+
+  /**
+   * All objects are being allocated at map creation. Those objects are "free"
+   * or empty. Whenever a new pair comes along, a pair is being "allocated" or
+   * taken from the free-linked list. as this is just a free list.
+   */
+  private int firstEmpty;
+
+  /** hashFactor is always (2^(N+1)) - 1. Used for faster hashing. */
+  private int hashFactor;
+
+  /** Holds the unique keys. */
+  Object[] keys;
+
+  /**
+   * In case of collisions, we implement a double linked list of the colliding
+   * hash's with the following next[] and prev[]. Those are also used to store
+   * the "empty" list.
+   */
+  int[] next;
+
+  private int prev;
+
+  /** Number of currently stored objects in the map. */
+  private int size;
+
+  /** Holds the values. */
+  Object[] values;
+
+  /** Constructs a map with default capacity. */
+  public ArrayHashMap() {
+    this(DEFAULT_CAPACITY);
+  }
+
+  /**
+   * Constructs a map with given capacity. Capacity is adjusted to a native
+   * power of 2, with minimum of 16.
+   * 
+   * @param capacity minimum capacity for the map.
+   */
+  public ArrayHashMap(int capacity) {
+    this.capacity = 16;
+    while (this.capacity < capacity) {
+      // Multiply by 2 as long as we're still under the requested capacity
+      this.capacity <<= 1;
+    }
+
+    // As mentioned, we use the first index (0) as 'Ground', so we need the
+    // length of the arrays to be one more than the capacity
+    int arrayLength = this.capacity + 1;
+
+    values = new Object[arrayLength];
+    keys = new Object[arrayLength];
+    next = new int[arrayLength];
+
+    // Hash entries are twice as big as the capacity.
+    int baseHashSize = this.capacity << 1;
+
+    baseHash = new int[baseHashSize];
+
+    // The has factor is 2^M - 1 which is used as an "AND" hashing operator.
+    // {@link #calcBaseHash()}
+    hashFactor = baseHashSize - 1;
+
+    size = 0;
+
+    clear();
+  }
+
+  /**
+   * Adds a pair to the map. Takes the first empty position from the
+   * empty-linked-list's head - {@link firstEmpty}. New pairs are always
+   * inserted to baseHash, and are followed by the old colliding pair.
+   */
+  private void prvt_put(K key, V value) {
+    // Hash entry to which the new pair would be inserted
+    int hashIndex = calcBaseHashIndex(key);
+
+    // 'Allocating' a pair from the "Empty" list.
+    int objectIndex = firstEmpty;
+
+    // Setting data
+    firstEmpty = next[firstEmpty];
+    values[objectIndex] = value;
+    keys[objectIndex] = key;
+
+    // Inserting the new pair as the first node in the specific hash entry
+    next[objectIndex] = baseHash[hashIndex];
+    baseHash[hashIndex] = objectIndex;
+
+    // Announcing a new pair was added!
+    ++size;
+  }
+
+  /** Calculating the baseHash index using the internal internal <code>hashFactor</code>. */
+  protected int calcBaseHashIndex(K key) {
+    return key.hashCode() & hashFactor;
+  }
+
+  /** Empties the map. Generates the "Empty" space list for later allocation. */
+  public void clear() {
+    // Clears the hash entries
+    Arrays.fill(baseHash, 0);
+
+    // Set size to zero
+    size = 0;
+
+    // Mark all array entries as empty. This is done with
+    // <code>firstEmpty</code> pointing to the first valid index (1 as 0 is
+    // used as 'Ground').
+    firstEmpty = 1;
+
+    // And setting all the <code>next[i]</code> to point at
+    // <code>i+1</code>.
+    for (int i = 1; i < capacity;) {
+      next[i] = ++i;
+    }
+
+    // Surly, the last one should point to the 'Ground'.
+    next[capacity] = 0;
+  }
+
+  /** Returns true iff the key exists in the map. */
+  public boolean containsKey(K key) {
+    return find(key) != 0;
+  }
+
+  /** Returns true iff the object exists in the map. */
+  public boolean containsValue(Object o) {
+    for (Iterator<V> iterator = iterator(); iterator.hasNext();) {
+      V object = iterator.next();
+      if (object.equals(o)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
+  /** Returns the index of the given key, or zero if the key wasn't found. */
+  protected int find(K key) {
+    // Calculate the hash entry.
+    int baseHashIndex = calcBaseHashIndex(key);
+
+    // Start from the hash entry.
+    int localIndex = baseHash[baseHashIndex];
+
+    // while the index does not point to the 'Ground'
+    while (localIndex != 0) {
+      // returns the index found in case of of a matching key.
+      if (keys[localIndex].equals(key)) {
+        return localIndex;
+      }
+
+      // next the local index
+      localIndex = next[localIndex];
+    }
+
+    // If we got this far, it could only mean we did not find the key we
+    // were asked for. return 'Ground' index.
+    return 0;
+  }
+
+  /**
+   * Finds the actual index of a given key with it's baseHashIndex. Some methods
+   * use the baseHashIndex. If those call {@link #find()} there's no need to
+   * re-calculate that hash.
+   * 
+   * @return the index of the given key, or 0 if the key wasn't found.
+   */
+  private int findForRemove(K key, int baseHashIndex) {
+    // Start from the hash entry.
+    prev = 0;
+    int index = baseHash[baseHashIndex];
+
+    // while the index does not point to the 'Ground'
+    while (index != 0) {
+      // returns the index found in case of of a matching key.
+      if (keys[index].equals(key)) {
+        return index;
+      }
+
+      // next the local index
+      prev = index;
+      index = next[index];
+    }
+
+    // If we got thus far, it could only mean we did not find the key we
+    // were asked for. return 'Ground' index.
+    return prev = 0;
+  }
+
+  /** Returns the object mapped with the given key, or null if the key wasn't found. */
+  @SuppressWarnings("unchecked")
+  public V get(K key) {
+    return (V) values[find(key)];
+  }
+
+  /**
+   * Allocates a new map of double the capacity, and fast-insert the old
+   * key-value pairs.
+   */
+  @SuppressWarnings("unchecked")
+  protected void grow() {
+    ArrayHashMap<K,V> newmap = new ArrayHashMap<K,V>(capacity * 2);
+
+    // Iterates fast over the collection. Any valid pair is put into the new
+    // map without checking for duplicates or if there's enough space for
+    // it.
+    for (IndexIterator iterator = new IndexIterator(); iterator.hasNext();) {
+      int index = iterator.next();
+      newmap.prvt_put((K) keys[index], (V) values[index]);
+    }
+
+    // Copy that's data into this.
+    capacity = newmap.capacity;
+    size = newmap.size;
+    firstEmpty = newmap.firstEmpty;
+    values = newmap.values;
+    keys = newmap.keys;
+    next = newmap.next;
+    baseHash = newmap.baseHash;
+    hashFactor = newmap.hashFactor;
+  }
+
+  /** Returns true iff the map is empty. */
+  public boolean isEmpty() {
+    return size == 0;
+  }
+
+  /** Returns an iterator on the mapped objects. */
+  public Iterator<V> iterator() {
+    return new ValueIterator();
+  }
+
+  /** Returns an iterator on the map keys. */
+  public Iterator<K> keyIterator() {
+    return new KeyIterator();
+  }
+
+  /** Prints the baseHash array, used for debugging purposes. */
+  @SuppressWarnings("unused")
+  private void printBaseHash() {
+    for (int i : baseHash) {
+      System.out.println(i + ".\t" + i);
+    }
+  }
+
+  /**
+   * Inserts the &lt;key,value&gt; pair into the map. If the key already exists,
+   * this method updates the mapped value to the given one, returning the old
+   * mapped value.
+   * 
+   * @return the old mapped value, or null if the key didn't exist.
+   */
+  @SuppressWarnings("unchecked")
+  public V put(K key, V e) {
+    // Does key exists?
+    int index = find(key);
+
+    // Yes!
+    if (index != 0) {
+      // Set new data and exit.
+      V old = (V) values[index];
+      values[index] = e;
+      return old;
+    }
+
+    // Is there enough room for a new pair?
+    if (size == capacity) {
+      // No? Than grow up!
+      grow();
+    }
+
+    // Now that everything is set, the pair can be just put inside with no
+    // worries.
+    prvt_put(key, e);
+
+    return null;
+  }
+
+  /**
+   * Removes a &lt;key,value&gt; pair from the map and returns the mapped value,
+   * or null if the none existed.
+   * 
+   * @param key used to find the value to remove
+   * @return the removed value or null if none existed.
+   */
+  @SuppressWarnings("unchecked")
+  public V remove(K key) {
+    int baseHashIndex = calcBaseHashIndex(key);
+    int index = findForRemove(key, baseHashIndex);
+    if (index != 0) {
+      // If it is the first in the collision list, we should promote its
+      // next colliding element.
+      if (prev == 0) {
+        baseHash[baseHashIndex] = next[index];
+      }
+
+      next[prev] = next[index];
+      next[index] = firstEmpty;
+      firstEmpty = index;
+      --size;
+      return (V) values[index];
+    }
+
+    return null;
+  }
+
+  /** Returns number of pairs currently in the map. */
+  public int size() {
+    return this.size;
+  }
+
+  /**
+   * Translates the mapped pairs' values into an array of Objects
+   * 
+   * @return an object array of all the values currently in the map.
+   */
+  public Object[] toArray() {
+    int j = -1;
+    Object[] array = new Object[size];
+
+    // Iterates over the values, adding them to the array.
+    for (Iterator<V> iterator = iterator(); iterator.hasNext();) {
+      array[++j] = iterator.next();
+    }
+    return array;
+  }
+
+  /**
+   * Translates the mapped pairs' values into an array of V
+   * 
+   * @param a the array into which the elements of the list are to be stored, if
+   *        it is big enough; otherwise, use as much space as it can.
+   * @return an array containing the elements of the list
+   */
+  public V[] toArray(V[] a) {
+    int j = 0;
+    // Iterates over the values, adding them to the array.
+    for (Iterator<V> iterator = iterator(); j < a.length
+    && iterator.hasNext(); ++j) {
+      a[j] = iterator.next();
+    }
+    if (j < a.length) {
+      a[j] = null;
+    }
+
+    return a;
+  }
+
+  @Override
+  public String toString() {
+    StringBuffer sb = new StringBuffer();
+    sb.append('{');
+    Iterator<K> keyIterator = keyIterator();
+    while (keyIterator.hasNext()) {
+      K key = keyIterator.next();
+      sb.append(key);
+      sb.append('=');
+      sb.append(get(key));
+      if (keyIterator.hasNext()) {
+        sb.append(',');
+        sb.append(' ');
+      }
+    }
+    sb.append('}');
+    return sb.toString();
+  }
+
+  @Override
+  public int hashCode() {
+    return getClass().hashCode() ^ size();
+  }
+
+  @SuppressWarnings("unchecked")
+  @Override
+  public boolean equals(Object o) {
+    ArrayHashMap<K, V> that = (ArrayHashMap<K,V>)o;
+    if (that.size() != this.size()) {
+      return false;
+    }
+
+    Iterator<K> it = keyIterator();
+    while (it.hasNext()) {
+      K key = it.next();
+      V v1 = this.get(key);
+      V v2 = that.get(key);
+      if ((v1 == null && v2 != null) ||
+          (v1 != null && v2 == null) ||
+          (!v1.equals(v2))) {
+        return false;
+      }
+    }
+    return true;
+  }
+}
\ No newline at end of file