com.netflix.zeno.util.collections.impl.AbstractArrayMap Maven / Gradle / Ivy
/*
*
* Copyright 2013 Netflix, Inc.
*
* 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.netflix.zeno.util.collections.impl;
import com.netflix.zeno.util.collections.builder.MapBuilder;
import java.util.AbstractCollection;
import java.util.AbstractMap.SimpleImmutableEntry;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* Abstract class which helps people to write Array based immutable
* implementations of the Map interface
*
* @author tvaliulin
*
* @param
* @param
*/
public abstract class AbstractArrayMap implements Map, MapBuilder {
protected static final Object undefined = new Object();
public AbstractArrayMap() {
}
public AbstractArrayMap(AbstractArrayMap map, int start, int end) {
builderInit(end - start);
for (int i = start; i < end; i++) {
builderPut(i - start, map.key(i), map.value(i));
}
builderFinish();
}
public abstract Object getUndefined(Object key);
@Override
public abstract int size();
protected abstract K key(int index);
protected abstract V value(int index);
@Override
public abstract void builderInit(int size);
@Override
public abstract void builderPut(int index, K key, V value);
@Override
public abstract Map builderFinish();
public void setMap(Map map) {
builderInit(map.size());
int i = 0;
for (Map.Entry entry : map.entrySet()) {
builderPut(i++, entry.getKey(), entry.getValue());
}
builderFinish();
}
public void setMap(Map.Entry[] entries) {
builderInit(entries.length);
int i = 0;
for (Map.Entry entry : entries) {
builderPut(i++, entry.getKey(), entry.getValue());
}
builderFinish();
}
@Override
public boolean isEmpty() {
return size() == 0;
}
@SuppressWarnings("unchecked")
@Override
public V get(Object key) {
Object result = getUndefined(key);
if (result == undefined) {
return null;
} else {
return (V) result;
}
}
@Override
public boolean containsKey(Object key) {
return undefined != getUndefined(key);
}
@Override
public boolean containsValue(Object value) {
for (int i = 0; i < size(); i++) {
if (value(i) == value) {
return true;
}
if (value != null && value.equals(value(i))) {
return true;
}
}
return false;
}
@SuppressWarnings("unchecked")
@Override
public boolean equals(Object o) {
if (o == this)
return true;
if (!(o instanceof Map))
return false;
Map m = (Map) o;
if (m.size() != size())
return false;
try {
Iterator> i = entrySet().iterator();
while (i.hasNext()) {
Entry e = i.next();
K key = e.getKey();
V value = e.getValue();
if (value == null) {
if (!(m.get(key) == null && m.containsKey(key)))
return false;
} else {
if (!value.equals(m.get(key)))
return false;
}
}
} catch (ClassCastException unused) {
return false;
} catch (NullPointerException unused) {
return false;
}
return true;
}
@Override
public int hashCode() {
int h = 0;
Iterator> i = entrySet().iterator();
while (i.hasNext())
h += i.next().hashCode();
return h;
}
@Override
public V put(K key, V value) {
throw new UnsupportedOperationException();
}
@Override
public V remove(Object key) {
throw new UnsupportedOperationException();
}
@Override
public void putAll(Map m) {
throw new UnsupportedOperationException();
}
@Override
public void clear() {
throw new UnsupportedOperationException();
}
@Override
public Set keySet() {
return new KeySet();
}
@Override
public Collection values() {
return new ValueCollection();
}
@Override
public Set> entrySet() {
return new EntrySet();
}
private class KeyValueIterator implements Iterator {
boolean key;
int cursor; // index of next element to return
int lastRet = -1; // index of last element returned; -1 if no such
public KeyValueIterator(boolean key) {
this.key = key;
}
@Override
public boolean hasNext() {
return cursor != AbstractArrayMap.this.size();
}
@SuppressWarnings("unchecked")
@Override
public E next() {
int i = cursor;
if (i >= AbstractArrayMap.this.size())
throw new NoSuchElementException();
cursor = i + 1;
lastRet = i;
return key ? (E) AbstractArrayMap.this.key(lastRet) : (E) AbstractArrayMap.this.value(lastRet);
}
@Override
public void remove() {
if (lastRet < 0)
throw new IllegalStateException();
try {
AbstractArrayMap.this.remove(key(lastRet));
cursor = lastRet;
lastRet = -1;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
}
}
private class KeySet extends AbstractSet {
@Override
public Iterator iterator() {
return new KeyValueIterator(true);
}
@Override
public boolean contains(Object o) {
return AbstractArrayMap.this.containsKey(o);
}
@Override
public int size() {
return AbstractArrayMap.this.size();
}
}
private class ValueCollection extends AbstractCollection {
@Override
public Iterator iterator() {
return new KeyValueIterator(false);
}
@Override
public int size() {
return AbstractArrayMap.this.size();
}
}
private class EntryIterator implements Iterator> {
int cursor; // index of next element to return
int lastRet = -1; // index of last element returned; -1 if no such
@Override
public boolean hasNext() {
return cursor != AbstractArrayMap.this.size();
}
@Override
public Entry next() {
int i = cursor;
if (i >= AbstractArrayMap.this.size())
throw new NoSuchElementException();
cursor = i + 1;
lastRet = i;
return new SimpleImmutableEntry(key(lastRet), value(lastRet));
}
@Override
public void remove() {
if (lastRet < 0)
throw new IllegalStateException();
try {
AbstractArrayMap.this.remove(key(lastRet));
cursor = lastRet;
lastRet = -1;
} catch (IndexOutOfBoundsException ex) {
throw new ConcurrentModificationException();
}
}
}
private class EntrySet extends AbstractSet> {
@Override
public Iterator> iterator() {
return new EntryIterator();
}
@Override
public int size() {
return AbstractArrayMap.this.size();
}
}
protected int hashCode(Object o) {
return o == null ? 0 : rehash(o.hashCode());
}
protected int rehash(int hash) {
return hash;
}
}