| /** |
| * |
| * 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.yoko.rmi.util; |
| |
| import java.util.Iterator; |
| import java.util.Map; |
| import java.util.NoSuchElementException; |
| |
| /** |
| * Class <code>DynamicHashMap</code> is a generic dynamic hash map. |
| */ |
| public class DynamicHashMap extends GenericMap implements Map { |
| class Entry extends GenericMap.Entry { |
| Entry next; |
| |
| int hash; |
| |
| Object key; |
| |
| Object value; |
| |
| Entry(int hash, Object key, Object value, Entry next) { |
| this.hash = hash; |
| this.key = key; |
| this.value = value; |
| this.next = next; |
| } |
| |
| public Object getKey() { |
| return key; |
| } |
| |
| public Object getValue() { |
| return value; |
| } |
| |
| public Object setValue(Object value) { |
| Object result = this.value; |
| this.value = value; |
| return result; |
| } |
| |
| boolean sameKey(int hash, Object key) { |
| return this.hash == hash && keyEquals(this.key, key); |
| } |
| } |
| |
| /** the hash index */ |
| private Entry[] table; |
| |
| /** the current range for table. */ |
| private int range; |
| |
| private float ratio; |
| |
| /** translate hash code bucket to index */ |
| private int index(int hash) { |
| return (hash & 0x7ffffff) % range; |
| } |
| |
| /** the default and only constructor */ |
| public DynamicHashMap() { |
| clear(); |
| } |
| |
| public void clear() { |
| range = 3; |
| size = 0; |
| ratio = 0.75F; |
| table = new Entry[range]; |
| } |
| |
| /** return the element with the given key */ |
| public Object get(Object key) { |
| int hash = keyHash(key); |
| return get(hash, key); |
| } |
| |
| public Object get(int hash, Object key) { |
| int idx = index(hash); |
| |
| for (Entry ent = table[idx]; ent != null; ent = ent.next) { |
| if (ent.sameKey(hash, key)) |
| return ent.value; |
| } |
| |
| return null; |
| } |
| |
| /** return the element with the given key */ |
| public boolean containsKey(Object key) { |
| int hash = keyHash(key); |
| return containsKey(hash, key); |
| } |
| |
| public boolean containsKey(int hash, Object key) { |
| int idx = index(hash); |
| |
| for (Entry ent = table[idx]; ent != null; ent = ent.next) { |
| if (ent.sameKey(hash, key)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| public Object put(Object key, Object value) { |
| int hash = keyHash(key); |
| return put(hash, key, value); |
| } |
| |
| public Object put(int hash, Object key, Object value) { |
| int idx = index(hash); |
| |
| for (Entry ent = table[idx]; ent != null; ent = ent.next) { |
| if (ent.sameKey(hash, key)) { |
| return ent.setValue(value); |
| } |
| } |
| |
| if (1.0F * size / range > ratio) { |
| grow(); |
| idx = index(hash); |
| } |
| |
| table[idx] = new Entry(hash, key, value, table[idx]); |
| |
| size += 1; |
| |
| return null; |
| } |
| |
| public Object remove(Object key) { |
| int hash = keyHash(key); |
| return remove(hash, key); |
| } |
| |
| public Object remove(int hash, Object key) { |
| int idx = index(hash); |
| |
| Entry entry = table[idx]; |
| if (entry != null) { |
| |
| if (entry.sameKey(hash, key)) { |
| table[idx] = entry.next; |
| size -= 1; |
| return entry.getValue(); |
| |
| } else { |
| Entry ahead = entry.next; |
| |
| while (ahead != null) { |
| if (ahead.sameKey(hash, key)) { |
| entry.next = ahead.next; |
| size -= 1; |
| return ahead.getValue(); |
| } |
| |
| entry = ahead; |
| ahead = ahead.next; |
| } |
| } |
| } |
| |
| // it was not found at all! |
| return null; |
| } |
| |
| private void grow() { |
| int old_range = range; |
| Entry[] old_table = table; |
| |
| range = old_range * 2 + 1; |
| table = new Entry[range]; |
| |
| for (int i = 0; i < old_range; i++) { |
| Entry entry = old_table[i]; |
| |
| while (entry != null) { |
| Entry ahead = entry.next; |
| int idx = index(entry.hash); |
| entry.next = table[idx]; |
| table[idx] = entry; |
| entry = ahead; |
| } |
| } |
| } |
| |
| final class EntryIterator implements Iterator { |
| int idx; |
| |
| Entry entry; |
| |
| EntryIterator() { |
| idx = 0; |
| entry = table[0]; |
| locateNext(); |
| } |
| |
| private void locateNext() { |
| // we reached the end of a list |
| while (entry == null) { |
| // goto next bucket |
| idx += 1; |
| if (idx == range) { |
| // we reached the end |
| return; |
| } |
| |
| // entry is the first element of this bucket |
| entry = table[idx]; |
| } |
| } |
| |
| public boolean hasNext() { |
| return (entry != null); |
| } |
| |
| public Object next() { |
| Object result = entry; |
| |
| if (result == null) { |
| throw new NoSuchElementException(); |
| } else { |
| entry = entry.next; |
| locateNext(); |
| return result; |
| } |
| } |
| |
| public void remove() { |
| Entry remove = entry; |
| |
| entry = entry.next; |
| locateNext(); |
| |
| DynamicHashMap.this.remove(remove.key); |
| } |
| } |
| |
| protected Iterator entryIterator() { |
| return new EntryIterator(); |
| } |
| |
| } |