/*
* Copyright 2015 the original author or authors.
* @https://github.com/scouter-project/scouter
*
* 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.
*
*
* The initial idea for this class is from "org.apache.commons.lang.IntHashMap";
* http://commons.apache.org/commons-lang-2.6-src.zip
*
*/
package scouter.util;
import java.util.Enumeration;
import java.util.NoSuchElementException;
public class StringHashCacheMap {
private static final int DEFAULT_CAPACITY = 101;
private static final float DEFAULT_LOAD_FACTOR = 0.75f;
private ENTRY table[];
private ENTRY header;
private int count;
private int threshold;
private float loadFactor;
public StringHashCacheMap(int initCapacity, float loadFactor) {
if (initCapacity < 0)
throw new RuntimeException("Capacity Error: " + initCapacity);
if (loadFactor <= 0)
throw new RuntimeException("Load Count Error: " + loadFactor);
if (initCapacity == 0)
initCapacity = 1;
this.loadFactor = loadFactor;
this.table = new ENTRY[initCapacity];
this.header = new ENTRY(null, 0, null);
this.header.link_next = header.link_prev = header;
threshold = (int) (initCapacity * loadFactor);
}
public StringHashCacheMap() {
this(DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR);
}
public int size() {
return count;
}
public String[] keyArray() {
String[] _keys = new String[this.size()];
StringEnumer en = this.keys();
for (int i = 0; i < _keys.length; i++)
_keys[i] = en.nextString();
return _keys;
}
public synchronized StringEnumer keys() {
return new Enumer(TYPE.KEYS);
}
public synchronized IntEnumer values() {
return new Enumer(TYPE.VALUES);
}
public synchronized Enumeration<ENTRY> myEntries() {
return new Enumer(TYPE.ENTRIES);
}
public synchronized boolean containsValue(int value) {
ENTRY tab[] = table;
int i = tab.length;
while (i-- > 0) {
for (ENTRY e = tab[i]; e != null; e = e.next) {
if (e.value == value) {
return true;
}
}
}
return false;
}
public synchronized boolean containsKey(String key) {
ENTRY tab[] = table;
int index = hash(key) % tab.length;
for (ENTRY e = tab[index]; e != null; e = e.next) {
if (e.key == key) {
return true;
}
}
return false;
}
public synchronized int get(String key) {
if (key == null)
return 0;
ENTRY tab[] = table;
int index = hash(key) % tab.length;
for (ENTRY e = tab[index]; e != null; e = e.next) {
if (e.key == key) {
return e.value;
}
}
return 0;
}
public synchronized int getFirsValue() {
if (isEmpty())
return 0;
return this.header.link_next.value;
}
public synchronized int getLastValue() {
if (isEmpty())
return 0;
return this.header.link_prev.value;
}
private int hash(String key) {
return key.hashCode() & Integer.MAX_VALUE;
}
protected void rehash() {
int oldCapacity = table.length;
ENTRY oldMap[] = table;
int newCapacity = oldCapacity * 2 + 1;
ENTRY newMap[] = new ENTRY[newCapacity];
threshold = (int) (newCapacity * loadFactor);
table = newMap;
for (int i = oldCapacity; i-- > 0;) {
ENTRY old = oldMap[i];
while (old != null) {
ENTRY e = old;
old = old.next;
String key = e.key;
int index = hash(key) % newCapacity;
e.next = newMap[index];
newMap[index] = e;
}
}
}
private int max;
public StringHashCacheMap setMax(int max) {
this.max = max;
return this;
}
private static enum MODE {
FORCE_FIRST, FORCE_LAST, FIRST, LAST
};
public int put(String key, int value) {
return _put(key, value, MODE.LAST);
}
public int putLast(String key, int value) {
return _put(key, value, MODE.FORCE_LAST);
}
public int putFirst(String key, int value) {
return _put(key, value, MODE.FORCE_FIRST);
}
private synchronized int _put(String key, int value, MODE m) {
if (key == null)
return 0;
ENTRY tab[] = table;
int index = hash(key) % tab.length;
for (ENTRY e = tab[index]; e != null; e = e.next) {
if (e.key == key) {
int old = e.value;
e.value = value;
switch (m) {
case FORCE_FIRST:
if (header.link_next != e) {
unchain(e);
chain(header, header.link_next, e);
}
break;
case FORCE_LAST:
if (header.link_prev != e) {
unchain(e);
chain(header.link_prev, header, e);
}
break;
}
return old;
}
}
if (max > 0) {
switch (m) {
case FORCE_FIRST:
case FIRST:
while (count >= max) {
removeLast();
}
break;
case FORCE_LAST:
case LAST:
while (count >= max) {
removeFirst();
}
break;
}
}
if (count >= threshold) {
rehash();
tab = table;
index = hash(key) % tab.length;
}
ENTRY e = new ENTRY(key, value, tab[index]);
tab[index] = e;
switch (m) {
case FORCE_FIRST:
case FIRST:
chain(header, header.link_next, e);
break;
case FORCE_LAST:
case LAST:
chain(header.link_prev, header, e);
break;
}
count++;
return 0;
}
public synchronized int remove(String key) {
if (key == null)
return 0;
ENTRY tab[] = table;
int index = hash(key) % tab.length;
for (ENTRY e = tab[index], prev = null; e != null; prev = e, e = e.next) {
if (e.key == key) {
if (prev != null) {
prev.next = e.next;
} else {
tab[index] = e.next;
}
count--;
int oldValue = e.value;
e.value = 0;
//
unchain(e);
return oldValue;
}
}
return 0;
}
public synchronized int removeFirst() {
if (isEmpty())
return 0;
return remove(header.link_next.key);
}
public synchronized int removeLast() {
if (isEmpty())
return 0;
return remove(header.link_prev.key);
}
public boolean isEmpty() {
return size() == 0;
}
public synchronized void clear() {
ENTRY tab[] = table;
for (int index = tab.length; --index >= 0;)
tab[index] = null;
this.header.link_next = header.link_prev = header;
count = 0;
}
public String toString() {
StringBuffer buf = new StringBuffer();
Enumeration it = myEntries();
buf.append("{");
for (int i = 0; it.hasMoreElements(); i++) {
ENTRY e = (ENTRY) (it.nextElement());
if (i > 0)
buf.append(", ");
buf.append(e.getKey() + "=" + e.getValue());
}
buf.append("}");
return buf.toString();
}
public String toFormatString() {
StringBuffer buf = new StringBuffer();
Enumeration it = myEntries();
buf.append("{\n");
while (it.hasMoreElements()) {
ENTRY e = (ENTRY) it.nextElement();
buf.append("\t").append(e.getKey() + "=" + e.getValue()).append("\n");
}
buf.append("}");
return buf.toString();
}
public static class ENTRY {
String key;
int value;
ENTRY next;
ENTRY link_next, link_prev;
protected ENTRY(String key, int value, ENTRY next) {
this.key = key;
this.value = value;
this.next = next;
}
protected Object clone() {
return new ENTRY(key, value, (next == null ? null : (ENTRY) next.clone()));
}
public String getKey() {
return key;
}
public int getValue() {
return value;
}
public int setValue(int value) {
int oldValue = this.value;
this.value = value;
return oldValue;
}
public boolean equals(Object o) {
if (!(o instanceof ENTRY))
return false;
ENTRY e = (ENTRY) o;
return e.key == key && e.value == value;
}
public int hashCode() {
return key.hashCode() ^ value;
}
public String toString() {
return key + "=" + value;
}
}
private enum TYPE {
KEYS, VALUES, ENTRIES
}
private class Enumer implements Enumeration, StringEnumer, IntEnumer {
TYPE type;
ENTRY myEntry = StringHashCacheMap.this.header.link_next;
Enumer(TYPE type) {
this.type = type;
}
public boolean hasMoreElements() {
return header != myEntry && myEntry != null;
}
public Object nextElement() {
if (hasMoreElements()) {
ENTRY e = myEntry;
myEntry = e.link_next;
switch (type) {
case KEYS:
return e.key;
case VALUES:
return e.value;
default:
return e;
}
}
throw new NoSuchElementException("no more next");
}
public int nextInt() {
if (hasMoreElements()) {
ENTRY e = myEntry;
myEntry = e.link_next;
return e.value;
}
throw new NoSuchElementException("no more next");
}
public String nextString() {
if (hasMoreElements()) {
ENTRY e = myEntry;
myEntry = e.link_next;
return e.key;
}
throw new NoSuchElementException("no more next");
}
}
private void chain(ENTRY link_prev, ENTRY link_next, ENTRY e) {
e.link_prev = link_prev;
e.link_next = link_next;
link_prev.link_next = e;
link_next.link_prev = e;
}
private void unchain(ENTRY e) {
e.link_prev.link_next = e.link_next;
e.link_next.link_prev = e.link_prev;
e.link_prev = null;
e.link_next = null;
}
public static void main(String[] args) {
}
private static void print(Object e) {
System.out.println(e);
}
}