/*
    * Copyright (C) 2008 The Guava Authors
    *
    * 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.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.collect;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.annotations.GwtIncompatible;
  
  import java.io.IOException;
  import java.io.InvalidObjectException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.util.Collection;
  import java.util.Comparator;
  import java.util.Map.Entry;
  
  import javax.annotation.Nullable;
  
  /**
   * An immutable {@link ListMultimap} with reliable user-specified key and value
   * iteration order. Does not permit null keys or values.
   *
   * <p>Unlike {@link Multimaps#unmodifiableListMultimap(ListMultimap)}, which is
   * a <i>view</i> of a separate multimap which can still change, an instance of
   * {@code ImmutableListMultimap} contains its own data and will <i>never</i>
   * change. {@code ImmutableListMultimap} is convenient for
   * {@code public static final} multimaps ("constant multimaps") and also lets
   * you easily make a "defensive copy" of a multimap provided to your class by
   * a caller.
   *
   * <p><b>Note:</b> Although this class is not final, it cannot be subclassed as
   * it has no public or protected constructors. Thus, instances of this class
   * are guaranteed to be immutable.
   *
   * <p>See the Guava User Guide article on <a href=
   * "http://code.google.com/p/guava-libraries/wiki/ImmutableCollectionsExplained">
   * immutable collections</a>.
   *
   * @author Jared Levy
   * @since 2.0 (imported from Google Collections Library)
   */
  @GwtCompatible(serializable = true, emulated = true)
  public class ImmutableListMultimap<K, V>
      extends ImmutableMultimap<K, V>
      implements ListMultimap<K, V> {
  
    /** Returns the empty multimap. */
    // Casting is safe because the multimap will never hold any elements.
    @SuppressWarnings("unchecked")
    public static <K, V> ImmutableListMultimap<K, V> of() {
      return (ImmutableListMultimap<K, V>) EmptyImmutableListMultimap.INSTANCE;
    }
  
    /**
     * Returns an immutable multimap containing a single entry.
     */
    public static <K, V> ImmutableListMultimap<K, V> of(K k1, V v1) {
      ImmutableListMultimap.Builder<K, V> builder
          = ImmutableListMultimap.builder();
      builder.put(k1, v1);
      return builder.build();
    }
  
    /**
     * Returns an immutable multimap containing the given entries, in order.
     */
    public static <K, V> ImmutableListMultimap<K, V> of(K k1, V v1, K k2, V v2) {
      ImmutableListMultimap.Builder<K, V> builder
          = ImmutableListMultimap.builder();
      builder.put(k1, v1);
      builder.put(k2, v2);
      return builder.build();
    }
  
    /**
     * Returns an immutable multimap containing the given entries, in order.
     */
    public static <K, V> ImmutableListMultimap<K, V> of(
        K k1, V v1, K k2, V v2, K k3, V v3) {
      ImmutableListMultimap.Builder<K, V> builder
          = ImmutableListMultimap.builder();
      builder.put(k1, v1);
      builder.put(k2, v2);
      builder.put(k3, v3);
      return builder.build();
    }
 
   /**
    * Returns an immutable multimap containing the given entries, in order.
    */
   public static <K, V> ImmutableListMultimap<K, V> of(
       K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
     ImmutableListMultimap.Builder<K, V> builder
         = ImmutableListMultimap.builder();
     builder.put(k1, v1);
     builder.put(k2, v2);
     builder.put(k3, v3);
     builder.put(k4, v4);
     return builder.build();
   }
 
   /**
    * Returns an immutable multimap containing the given entries, in order.
    */
   public static <K, V> ImmutableListMultimap<K, V> of(
       K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
     ImmutableListMultimap.Builder<K, V> builder
         = ImmutableListMultimap.builder();
     builder.put(k1, v1);
     builder.put(k2, v2);
     builder.put(k3, v3);
     builder.put(k4, v4);
     builder.put(k5, v5);
     return builder.build();
   }
 
   // looking for of() with > 5 entries? Use the builder instead.
 
   /**
    * Returns a new builder. The generated builder is equivalent to the builder
    * created by the {@link Builder} constructor.
    */
   public static <K, V> Builder<K, V> builder() {
     return new Builder<K, V>();
   }
 
   /**
    * A builder for creating immutable {@code ListMultimap} instances, especially
    * {@code public static final} multimaps ("constant multimaps"). Example:
    * <pre>   {@code
    *
    *   static final Multimap<String, Integer> STRING_TO_INTEGER_MULTIMAP =
    *       new ImmutableListMultimap.Builder<String, Integer>()
    *           .put("one", 1)
    *           .putAll("several", 1, 2, 3)
    *           .putAll("many", 1, 2, 3, 4, 5)
    *           .build();}</pre>
    *
    * <p>Builder instances can be reused; it is safe to call {@link #build} multiple
    * times to build multiple multimaps in series. Each multimap contains the
    * key-value mappings in the previously created multimaps.
    *
    * @since 2.0 (imported from Google Collections Library)
    */
   public static final class Builder<K, V>
       extends ImmutableMultimap.Builder<K, V> {
     /**
      * Creates a new builder. The returned builder is equivalent to the builder
      * generated by {@link ImmutableListMultimap#builder}.
      */
     public Builder() {}
 
     @Override public Builder<K, V> put(K key, V value) {
       super.put(key, value);
       return this;
     }
 
     /**
      * {@inheritDoc}
      *
      * @since 11.0
      */
     @Override public Builder<K, V> put(
         Entry<? extends K, ? extends V> entry) {
       super.put(entry);
       return this;
     }
 
     @Override public Builder<K, V> putAll(K key, Iterable<? extends V> values) {
       super.putAll(key, values);
       return this;
     }
 
     @Override public Builder<K, V> putAll(K key, V... values) {
       super.putAll(key, values);
       return this;
     }
 
     @Override public Builder<K, V> putAll(
         Multimap<? extends K, ? extends V> multimap) {
       super.putAll(multimap);
       return this;
     }
 
     /**
      * {@inheritDoc}
      *
      * @since 8.0
      */
     @Override
     public Builder<K, V> orderKeysBy(Comparator<? super K> keyComparator) {
       super.orderKeysBy(keyComparator);
       return this;
     }
 
     /**
      * {@inheritDoc}
      *
      * @since 8.0
      */
     @Override
     public Builder<K, V> orderValuesBy(Comparator<? super V> valueComparator) {
       super.orderValuesBy(valueComparator);
       return this;
     }
 
     /**
      * Returns a newly-created immutable list multimap.
      */
     @Override public ImmutableListMultimap<K, V> build() {
       return (ImmutableListMultimap<K, V>) super.build();
     }
   }
 
   /**
    * Returns an immutable multimap containing the same mappings as {@code
    * multimap}. The generated multimap's key and value orderings correspond to
    * the iteration ordering of the {@code multimap.asMap()} view.
    *
    * <p>Despite the method name, this method attempts to avoid actually copying
    * the data when it is safe to do so. The exact circumstances under which a
    * copy will or will not be performed are undocumented and subject to change.
    *
    * @throws NullPointerException if any key or value in {@code multimap} is
    *         null
    */
   public static <K, V> ImmutableListMultimap<K, V> copyOf(
       Multimap<? extends K, ? extends V> multimap) {
     if (multimap.isEmpty()) {
       return of();
     }
 
     // TODO(user): copy ImmutableSetMultimap by using asList() on the sets
     if (multimap instanceof ImmutableListMultimap) {
       @SuppressWarnings("unchecked") // safe since multimap is not writable
       ImmutableListMultimap<K, V> kvMultimap
           = (ImmutableListMultimap<K, V>) multimap;
       if (!kvMultimap.isPartialView()) {
         return kvMultimap;
       }
     }
 
     ImmutableMap.Builder<K, ImmutableList<V>> builder = ImmutableMap.builder();
     int size = 0;
 
     for (Entry<? extends K, ? extends Collection<? extends V>> entry
         : multimap.asMap().entrySet()) {
       ImmutableList<V> list = ImmutableList.copyOf(entry.getValue());
       if (!list.isEmpty()) {
         builder.put(entry.getKey(), list);
         size += list.size();
       }
     }
 
     return new ImmutableListMultimap<K, V>(builder.build(), size);
   }
 
   ImmutableListMultimap(ImmutableMap<K, ImmutableList<V>> map, int size) {
     super(map, size);
   }
 
   // views
 
   /**
    * Returns an immutable list of the values for the given key.  If no mappings
    * in the multimap have the provided key, an empty immutable list is
    * returned. The values are in the same order as the parameters used to build
    * this multimap.
    */
   @Override public ImmutableList<V> get(@Nullable K key) {
     // This cast is safe as its type is known in constructor.
     ImmutableList<V> list = (ImmutableList<V>) map.get(key);
     return (list == null) ? ImmutableList.<V>of() : list;
   }
 
   private transient ImmutableListMultimap<V, K> inverse;
 
   /**
    * {@inheritDoc}
    *
    * <p>Because an inverse of a list multimap can contain multiple pairs with
    * the same key and value, this method returns an {@code
    * ImmutableListMultimap} rather than the {@code ImmutableMultimap} specified
    * in the {@code ImmutableMultimap} class.
    *
    * @since 11.0
    */
   @Override
   public ImmutableListMultimap<V, K> inverse() {
     ImmutableListMultimap<V, K> result = inverse;
     return (result == null) ? (inverse = invert()) : result;
   }
 
   private ImmutableListMultimap<V, K> invert() {
     Builder<V, K> builder = builder();
     for (Entry<K, V> entry : entries()) {
       builder.put(entry.getValue(), entry.getKey());
     }
     ImmutableListMultimap<V, K> invertedMultimap = builder.build();
     invertedMultimap.inverse = this;
     return invertedMultimap;
   }
 
   /**
    * Guaranteed to throw an exception and leave the multimap unmodified.
    *
    * @throws UnsupportedOperationException always
    * @deprecated Unsupported operation.
    */
   @Deprecated @Override public ImmutableList<V> removeAll(Object key) {
     throw new UnsupportedOperationException();
   }
 
   /**
    * Guaranteed to throw an exception and leave the multimap unmodified.
    *
    * @throws UnsupportedOperationException always
    * @deprecated Unsupported operation.
    */
   @Deprecated @Override public ImmutableList<V> replaceValues(
       K key, Iterable<? extends V> values) {
     throw new UnsupportedOperationException();
   }
 
   /**
    * @serialData number of distinct keys, and then for each distinct key: the
    *     key, the number of values for that key, and the key's values
    */
   @GwtIncompatible("java.io.ObjectOutputStream")
   private void writeObject(ObjectOutputStream stream) throws IOException {
     stream.defaultWriteObject();
     Serialization.writeMultimap(this, stream);
   }
 
   @GwtIncompatible("java.io.ObjectInputStream")
   private void readObject(ObjectInputStream stream)
       throws IOException, ClassNotFoundException {
     stream.defaultReadObject();
     int keyCount = stream.readInt();
     if (keyCount < 0) {
       throw new InvalidObjectException("Invalid key count " + keyCount);
     }
     ImmutableMap.Builder<Object, ImmutableList<Object>> builder
         = ImmutableMap.builder();
     int tmpSize = 0;
 
     for (int i = 0; i < keyCount; i++) {
       Object key = stream.readObject();
       int valueCount = stream.readInt();
       if (valueCount <= 0) {
         throw new InvalidObjectException("Invalid value count " + valueCount);
       }
 
       Object[] array = new Object[valueCount];
       for (int j = 0; j < valueCount; j++) {
         array[j] = stream.readObject();
       }
       builder.put(key, ImmutableList.copyOf(array));
       tmpSize += valueCount;
     }
 
     ImmutableMap<Object, ImmutableList<Object>> tmpMap;
     try {
       tmpMap = builder.build();
     } catch (IllegalArgumentException e) {
       throw (InvalidObjectException)
           new InvalidObjectException(e.getMessage()).initCause(e);
     }
 
     FieldSettersHolder.MAP_FIELD_SETTER.set(this, tmpMap);
     FieldSettersHolder.SIZE_FIELD_SETTER.set(this, tmpSize);
   }
 
   @GwtIncompatible("Not needed in emulated source")
   private static final long serialVersionUID = 0;
 }