Array Map extends AbstractMap : HashTable Map « Collections Data Structure « Java
Array Map extends AbstractMap
import java.io.Serializable;
import java.util.*;
public class ArrayMap extends AbstractMap
implements Cloneable, Serializable {
static class Entry implements Map.Entry {
protected Object key, value;
public Entry(Object key, Object value) {
this.key = key;
this.value = value;
}
public Object getKey() {
return key;
}
public Object getValue() {
return value;
}
public Object setValue(Object newValue) {
Object oldValue = value;
value = newValue;
return oldValue;
}
public boolean equals(Object o) {
if (!(o instanceof Map.Entry)) {
return false;
}
Map.Entry e = (Map.Entry)o;
return (key==null ? e.getKey()==null : key.equals(e.getKey())) &&
(value==null ? e.getValue()==null : value.equals(e.getValue()));
}
public int hashCode() {
int keyHash = (key==null ? 0 : key.hashCode());
int valueHash = (value==null ? 0 : value.hashCode());
return keyHash ^ valueHash;
}
public String toString() {
return key + "=" + value;
}
}
private Set entries = null;
private ArrayList list;
public ArrayMap() {
list = new ArrayList();
}
public ArrayMap(Map map) {
list = new ArrayList();
putAll(map);
}
public ArrayMap(int initialCapacity) {
list = new ArrayList(initialCapacity);
}
public Set entrySet() {
if (entries==null) {
entries = new AbstractSet() {
public void clear() {
list.clear();
}
public Iterator iterator() {
return list.iterator();
}
public int size() {
return list.size();
}
};
}
return entries;
}
public Object put(Object key, Object value) {
int size = list.size();
Entry entry = null;
int i;
if (key==null) {
for (i=0; i<size; i++) {
entry = (Entry)(list.get(i));
if (entry.getKey() == null) {
break;
}
}
} else {
for (i=0; i<size; i++) {
entry = (Entry)(list.get(i));
if (key.equals(entry.getKey())) {
break;
}
}
}
Object oldValue = null;
if (i<size) {
oldValue = entry.getValue();
entry.setValue(value);
} else {
list.add(new Entry(key, value));
}
return oldValue;
}
public Object clone() {
return new ArrayMap(this);
}
}
