Java tutorial
/*
* Copyright 2008-2009 the T2 Project ant the Others.
*
* 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 org.t2framework.commons.util;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.lang.reflect.Array;
import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
/**
* Array map.
*
* @author shot
*
* @param <K>
* @param <V>
*/
public class ArrayMap<K, V> extends AbstractMap<K, V> implements Map<K, V>,
Cloneable, Externalizable {
static final long serialVersionUID = 1L;
protected static final int INITIAL_CAPACITY = 17;
protected static final float LOAD_FACTOR = 0.75f;
protected transient int threshold;
protected transient Entry<K, V>[] mapTable;
protected transient Entry<K, V>[] listTable;
protected transient int size = 0;
protected transient Set<?> entrySet = null;
public static <K, V> ArrayMap<K, V> newArrayMap() {
return new ArrayMap<K, V>();
}
public ArrayMap() {
this(INITIAL_CAPACITY);
}
@SuppressWarnings("unchecked")
public ArrayMap(int initialCapacity) {
if (initialCapacity <= 0) {
initialCapacity = INITIAL_CAPACITY;
}
mapTable = new Entry[initialCapacity];
listTable = new Entry[initialCapacity];
threshold = (int) (initialCapacity * LOAD_FACTOR);
}
public ArrayMap(Map<K, V> map) {
this((int) (map.size() / LOAD_FACTOR) + 1);
putAll(map);
}
public final int size() {
return size;
}
public final boolean isEmpty() {
return size == 0;
}
public final boolean containsValue(Object value) {
return indexOf(value) >= 0;
}
public final int indexOf(Object value) {
if (value != null) {
for (int i = 0; i < size; i++) {
if (value.equals(listTable[i].value_)) {
return i;
}
}
} else {
for (int i = 0; i < size; i++) {
if (listTable[i].value_ == null) {
return i;
}
}
}
return -1;
}
public boolean containsKey(final Object key) {
Entry<K, V>[] tbl = mapTable;
if (key != null) {
int hashCode = key.hashCode();
int index = (hashCode & 0x7FFFFFFF) % tbl.length;
for (Entry<K, V> e = tbl[index]; e != null; e = e.next_) {
if (e.hashCode_ == hashCode && key.equals(e.key_)) {
return true;
}
}
} else {
for (Entry<K, V> e = tbl[0]; e != null; e = e.next_) {
if (e.key_ == null) {
return true;
}
}
}
return false;
}
public V get(final Object key) {
Entry<K, V>[] tbl = mapTable;
if (key != null) {
int hashCode = key.hashCode();
int index = (hashCode & 0x7FFFFFFF) % tbl.length;
for (Entry<K, V> e = tbl[index]; e != null; e = e.next_) {
if (e.hashCode_ == hashCode && key.equals(e.key_)) {
return e.value_;
}
}
} else {
for (Entry<K, V> e = tbl[0]; e != null; e = e.next_) {
if (e.key_ == null) {
return e.value_;
}
}
}
return null;
}
public final V get(final int index) {
return getEntry(index).value_;
}
public final K getKey(final int index) {
return getEntry(index).key_;
}
public final Entry<K, V> getEntry(final int index) {
if (index >= size) {
throw new IndexOutOfBoundsException("Index:" + index + ", Size:"
+ size);
}
return listTable[index];
}
public V put(final K key, final V value) {
int hashCode = 0;
int index = 0;
if (key != null) {
hashCode = key.hashCode();
index = (hashCode & 0x7FFFFFFF) % mapTable.length;
for (Entry<K, V> e = mapTable[index]; e != null; e = e.next_) {
if ((e.hashCode_ == hashCode) && key.equals(e.key_)) {
return swapValue(e, value);
}
}
} else {
for (Entry<K, V> e = mapTable[0]; e != null; e = e.next_) {
if (e.key_ == null) {
return swapValue(e, value);
}
}
}
ensureCapacity();
index = (hashCode & 0x7FFFFFFF) % mapTable.length;
Entry<K, V> e = new Entry<K, V>(hashCode, key, value, mapTable[index]);
mapTable[index] = e;
listTable[size++] = e;
return null;
}
public final void set(final int index, final V value) {
getEntry(index).setValue(value);
}
public V remove(final Object key) {
Entry<K, V> e = removeMap(key);
if (e != null) {
V value = e.value_;
removeList(indexOf(e));
e.clear();
return value;
}
return null;
}
public final Object remove(int index) {
Entry<K, V> e = removeList(index);
Object value = e.value_;
removeMap(e.key_);
e.value_ = null;
return value;
}
@SuppressWarnings("unchecked")
@Override
public void putAll(Map<? extends K, ? extends V> map) {
for (Iterator<?> i = map.entrySet().iterator(); i.hasNext();) {
Map.Entry<K, V> e = (Map.Entry<K, V>) i.next();
put(e.getKey(), e.getValue());
}
}
public final void clear() {
for (int i = 0; i < mapTable.length; i++) {
mapTable[i] = null;
}
for (int i = 0; i < listTable.length; i++) {
listTable[i] = null;
}
size = 0;
}
public final Object[] toArray() {
Object[] array = new Object[size];
for (int i = 0; i < array.length; i++) {
array[i] = get(i);
}
return array;
}
public final Object[] toArray(final Object proto[]) {
Object[] array = proto;
if (proto.length < size) {
array = (Object[]) Array.newInstance(proto.getClass()
.getComponentType(), size);
}
for (int i = 0; i < array.length; i++) {
array[i] = get(i);
}
if (array.length > size) {
array[size] = null;
}
return array;
}
@SuppressWarnings("unchecked")
public final boolean equals(Object o) {
if (!getClass().isInstance(o)) {
return false;
}
ArrayMap<K, V> e = (ArrayMap<K, V>) o;
if (size != e.size) {
return false;
}
for (int i = 0; i < size; i++) {
if (!listTable[i].equals(e.listTable[i])) {
return false;
}
}
return true;
}
@SuppressWarnings("unchecked")
public final Set entrySet() {
if (entrySet == null) {
entrySet = new AbstractSet() {
public Iterator iterator() {
return new ArrayMapIterator();
}
public boolean contains(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry) o;
int index = (entry.hashCode_ & 0x7FFFFFFF)
% mapTable.length;
for (Entry e = mapTable[index]; e != null; e = e.next_) {
if (e.equals(entry)) {
return true;
}
}
return false;
}
public boolean remove(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry entry = (Entry) o;
return ArrayMap.this.remove(entry.key_) != null;
}
public int size() {
return size;
}
public void clear() {
ArrayMap.this.clear();
}
};
}
return entrySet;
}
public final void writeExternal(final ObjectOutput out) throws IOException {
out.writeInt(listTable.length);
out.writeInt(size);
for (int i = 0; i < size; i++) {
out.writeObject(listTable[i].key_);
out.writeObject(listTable[i].value_);
}
}
@SuppressWarnings("unchecked")
public final void readExternal(final ObjectInput in) throws IOException,
ClassNotFoundException {
int num = in.readInt();
mapTable = new Entry[num];
listTable = new Entry[num];
threshold = (int) (num * LOAD_FACTOR);
int size = in.readInt();
for (int i = 0; i < size; i++) {
K key = (K) in.readObject();
V value = (V) in.readObject();
put(key, value);
}
}
public Object clone() {
ArrayMap<K, V> copy = new ArrayMap<K, V>();
copy.threshold = threshold;
copy.mapTable = mapTable;
copy.listTable = listTable;
copy.size = size;
return copy;
}
private final int indexOf(final Entry<K, V> entry) {
for (int i = 0; i < size; i++) {
if (listTable[i] == entry) {
return i;
}
}
return -1;
}
private final Entry<K, V> removeMap(Object key) {
int hashCode = 0;
int index = 0;
if (key != null) {
hashCode = key.hashCode();
index = (hashCode & 0x7FFFFFFF) % mapTable.length;
for (Entry<K, V> e = mapTable[index], prev = null; e != null; prev = e, e = e.next_) {
if ((e.hashCode_ == hashCode) && key.equals(e.key_)) {
if (prev != null) {
prev.next_ = e.next_;
} else {
mapTable[index] = e.next_;
}
return e;
}
}
} else {
for (Entry<K, V> e = mapTable[index], prev = null; e != null; prev = e, e = e.next_) {
if ((e.hashCode_ == hashCode) && e.key_ == null) {
if (prev != null) {
prev.next_ = e.next_;
} else {
mapTable[index] = e.next_;
}
return e;
}
}
}
return null;
}
private final Entry<K, V> removeList(int index) {
Entry<K, V> e = listTable[index];
int numMoved = size - index - 1;
if (numMoved > 0) {
System.arraycopy(listTable, index + 1, listTable, index, numMoved);
}
listTable[--size] = null;
return e;
}
@SuppressWarnings("unchecked")
private final void ensureCapacity() {
if (size >= threshold) {
Entry<K, V>[] oldTable = listTable;
int newCapacity = oldTable.length * 2 + 1;
Entry<K, V>[] newMapTable = new Entry[newCapacity];
Entry<K, V>[] newListTable = new Entry[newCapacity];
threshold = (int) (newCapacity * LOAD_FACTOR);
System.arraycopy(oldTable, 0, newListTable, 0, size);
for (int i = 0; i < size; i++) {
Entry<K, V> old = oldTable[i];
int index = (old.hashCode_ & 0x7FFFFFFF) % newCapacity;
Entry<K, V> e = old;
old = old.next_;
e.next_ = newMapTable[index];
newMapTable[index] = e;
}
mapTable = newMapTable;
listTable = newListTable;
}
}
private final V swapValue(final Entry<K, V> entry, final V value) {
V old = entry.value_;
entry.value_ = value;
return old;
}
private class ArrayMapIterator implements Iterator<Entry<K, V>> {
private int current_ = 0;
private int last_ = -1;
public boolean hasNext() {
return current_ != size;
}
public Entry<K, V> next() {
try {
Entry<K, V> n = listTable[current_];
last_ = current_++;
return n;
} catch (IndexOutOfBoundsException e) {
throw new NoSuchElementException();
}
}
public void remove() {
if (last_ == -1) {
throw new IllegalStateException();
}
ArrayMap.this.remove(last_);
if (last_ < current_) {
current_--;
}
last_ = -1;
}
}
private static class Entry<K, V> implements Map.Entry<K, V>, Externalizable {
private static final long serialVersionUID = -6625980241350717177L;
transient int hashCode_;
transient K key_;
transient V value_;
transient Entry<K, V> next_;
public Entry(final int hashCode, final K key, final V value,
final Entry<K, V> next) {
hashCode_ = hashCode;
key_ = key;
value_ = value;
next_ = next;
}
public K getKey() {
return key_;
}
public V getValue() {
return value_;
}
public V setValue(final V value) {
V oldValue = value_;
value_ = value;
return oldValue;
}
public void clear() {
key_ = null;
value_ = null;
next_ = null;
}
@SuppressWarnings("unchecked")
public boolean equals(final Object o) {
if (this == o) {
return true;
}
Entry<K, V> e = (Entry<K, V>) o;
return (key_ != null ? key_.equals(e.key_) : e.key_ == null)
&& (value_ != null ? value_.equals(e.value_)
: e.value_ == null);
}
public int hashCode() {
return hashCode_;
}
public String toString() {
return key_ + "=" + value_;
}
public void writeExternal(final ObjectOutput s) throws IOException {
s.writeInt(hashCode_);
s.writeObject(key_);
s.writeObject(value_);
s.writeObject(next_);
}
@SuppressWarnings("unchecked")
public void readExternal(final ObjectInput s) throws IOException,
ClassNotFoundException {
hashCode_ = s.readInt();
key_ = (K) s.readObject();
value_ = (V) s.readObject();
next_ = (Entry) s.readObject();
}
}
}-------------------
/*
* Copyright 2008-2009 the T2 Project ant the Others.
*
* 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 org.t2framework.commons.util;
import org.t2framework.commons.util.ArrayMap;
import junit.framework.TestCase;
public class ArrayMapTest extends TestCase {
public void test1() throws Exception {
ArrayMap<String, String> map = ArrayMap.newArrayMap();
map.put("aaa", "AAA");
map.put("bbb", "BBB");
assertEquals("AAA", map.get(0));
assertEquals("BBB", map.get("bbb"));
}
public void test2() throws Exception {
ArrayMap<String, String> map = ArrayMap.newArrayMap();
map.put("aaa", "AAA");
map.put("bbb", "BBB");
ArrayMap<String, String> map2 = ArrayMap.newArrayMap();
map2.put("ccc", "CCC");
map2.putAll(map);
assertEquals("CCC", map2.get(0));
assertEquals("BBB", map2.get("bbb"));
}
public void test3() throws Exception {
ArrayMap<String, String> map = ArrayMap.newArrayMap();
{
map.put("a", "A");
map.put("b", "B");
map.put("c", "C");
}
String key = map.getKey(0);
assertEquals("a", key);
assertTrue(map.containsKey("b"));
assertTrue(map.containsValue("A"));
assertEquals("C", map.get("c"));
assertTrue(map.indexOf("B") == 1);
Object[] array = map.toArray();
assertTrue(array.length == 3);
assertEquals("B", array[1]);
}
}