org.apache.felix.resolver.util.ArrayMap Maven / Gradle / Ivy
/*
* 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.felix.resolver.util;
import java.util.*;
public class ArrayMap extends AbstractMap {
private Object[] table;
private int size;
protected transient Collection values;
public ArrayMap() {
this(32);
}
public ArrayMap(int capacity) {
table = new Object[capacity * 2];
size = 0;
}
@Override
@SuppressWarnings("unchecked")
public V get(Object key) {
for (int i = 0, l = size << 1; i < l; i += 2) {
if (key.equals(table[i])) {
return (V) table[i + 1];
}
}
return null;
}
@Override
@SuppressWarnings("unchecked")
public V put(K key, V value) {
for (int i = 0, l = size << 1; i < l; i += 2) {
if (key.equals(table[i])) {
V old = (V) table[i + 1];
table[i + 1] = value;
return old;
}
}
if (size * 2 == table.length) {
Object[] n = new Object[table.length * 2];
System.arraycopy(table, 0, n, 0, table.length);
table = n;
}
int i = size++ << 1;
table[i++] = key;
table[i] = value;
return null;
}
@SuppressWarnings("unchecked")
public V getOrCompute(K key) {
for (int i = 0, l = size << 1; i < l; i += 2) {
if (key.equals(table[i])) {
return (V) table[i + 1];
}
}
V v = compute(key);
if (size << 1 == table.length) {
Object[] n = new Object[table.length << 1];
System.arraycopy(table, 0, n, 0, table.length);
table = n;
}
int i = size++ << 1;
table[i++] = key;
table[i] = v;
return v;
}
protected V compute(K key) {
throw new UnsupportedOperationException();
}
@Override
public Collection values() {
if (values == null) {
values = new AbstractCollection() {
@Override
public Iterator iterator() {
return new Iterator() {
int index = 0;
public boolean hasNext() {
return index < size;
}
@SuppressWarnings("unchecked")
public V next() {
if (index >= size) {
throw new NoSuchElementException();
}
return (V) table[(index++ << 1) + 1];
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public int size() {
return size;
}
};
}
return values;
}
@Override
public Set> entrySet() {
return new AbstractSet>() {
@Override
public Iterator> iterator() {
return new Iterator>() {
FastEntry entry = new FastEntry();
int index = 0;
public boolean hasNext() {
return index < size;
}
@SuppressWarnings("unchecked")
public FastEntry next() {
if (index >= size) {
throw new NoSuchElementException();
}
int i = index << 1;
entry.key = (K) table[i];
entry.value = (V) table[i + 1];
index++;
return entry;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public int size() {
return size;
}
};
}
static class FastEntry implements Entry {
K key;
V value;
public K getKey() {
return key;
}
public V getValue() {
return value;
}
public V setValue(V value) {
throw new UnsupportedOperationException();
}
}
}