| /* |
| * 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.cassandra.db.tries; |
| |
| import java.util.AbstractMap; |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| import org.apache.cassandra.utils.bytecomparable.ByteComparable; |
| |
| /** |
| * Convertor of trie entries to iterator where each entry is passed through {@link #mapContent} (to be implemented by |
| * descendants). |
| */ |
| public abstract class TrieEntriesIterator<T, V> extends TriePathReconstructor implements Iterator<V> |
| { |
| private final Trie.Cursor<T> cursor; |
| T next; |
| boolean gotNext; |
| |
| protected TrieEntriesIterator(Trie<T> trie) |
| { |
| cursor = trie.cursor(); |
| assert cursor.depth() == 0; |
| next = cursor.content(); |
| gotNext = next != null; |
| } |
| |
| public boolean hasNext() |
| { |
| if (!gotNext) |
| { |
| next = cursor.advanceToContent(this); |
| gotNext = true; |
| } |
| |
| return next != null; |
| } |
| |
| public V next() |
| { |
| gotNext = false; |
| T v = next; |
| next = null; |
| return mapContent(v, keyBytes, keyPos); |
| } |
| |
| protected abstract V mapContent(T content, byte[] bytes, int byteLength); |
| |
| /** |
| * Iterator representing the content of the trie a sequence of (path, content) pairs. |
| */ |
| static class AsEntries<T> extends TrieEntriesIterator<T, Map.Entry<ByteComparable, T>> |
| { |
| public AsEntries(Trie<T> trie) |
| { |
| super(trie); |
| } |
| |
| @Override |
| protected Map.Entry<ByteComparable, T> mapContent(T content, byte[] bytes, int byteLength) |
| { |
| return toEntry(content, bytes, byteLength); |
| } |
| } |
| |
| static <T> java.util.Map.Entry<ByteComparable, T> toEntry(T content, byte[] bytes, int byteLength) |
| { |
| return new AbstractMap.SimpleImmutableEntry<>(toByteComparable(bytes, byteLength), content); |
| } |
| } |