Re: Immutable Datastructures with good Sharing

From:
Jan Burse <janburse@fastmail.fm>
Newsgroups:
comp.lang.java.programmer
Date:
Mon, 07 Nov 2011 05:13:27 +0100
Message-ID:
<j97lt8$lu4$1@news.albasani.net>
Jan Burse schrieb:

I guess the putAll() results in cloning, therefore
no good sharing, therefore not a solution to the
problem at hand.

But I might be wrong.


Yep it is of no use.

First we have behind newArrayList the following:

   public static <E> ArrayList<E> newArrayList() {
     return new ArrayList<E>();
   }

 
http://code.google.com/p/google-collections/source/browse/trunk/src/com/google/common/collect/Lists.java

Then we have behind put and putAll():

     public static class Builder<K, V> {
        final List<Entry<K, V>> entries = Lists.newArrayList();

        public Builder<K, V> put(K key, V value) {
           entries.add(entryOf(key, value));
           return this;
        }

        public Builder<K, V> putAll(Map<? extends K, ? extends V> map) {
           for (Entry<? extends K, ? extends V> entry : map.entrySet()) {
             put(entry.getKey(), entry.getValue());
           }
           return this;
        }

 
http://www.docjar.com/html/api/com/google/inject/internal/ImmutableMap.java.html

So the whole thing, in version 1.0, doesn't make
much sense, except that it has the label
Google on it.

Bye

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