public V get(String key)
{
BaseNode branch = this;
char[] chars = key.toCharArray();
for (char aChar : chars)
{
if (branch == null)
{
return(null);
}
branch = branch.getChild(aChar);
}
if (branch == null)
{
return(null);
}
// 下面这句可以保证只有成词的节点被返回
if (!(branch.status == Status.WORD_END_3 || branch.status == Status.WORD_MIDDLE_2))
{
return(null);
}
return((V)branch.getValue());
}
public BaseNode <V> transition(char[] path, int begin)
{
BaseNode <V> cur = this;
for (int i = begin; i < path.Length; ++i)
{
cur = cur.getChild(path[i]);
if (cur == null || cur.status == Status.UNDEFINED_0)
{
return(null);
}
}
return(cur);
}
public void put(char[] key, V value)
{
BaseNode branch = this;
for (int i = 0; i < key.length - 1; ++i)
{
// 除了最后一个字外，都是继续
branch.addChild(new Node(key[i], Status.NOT_WORD_1, null));
branch = branch.getChild(key[i]);
}
// 最后一个字加入时属性为end
if (branch.addChild(new Node <V>(key[key.length - 1], Status.WORD_END_3, value)))
{
++size; // 维护size
}
}
public boolean containsKey(String key)
{
BaseNode branch = this;
char[] chars = key.toCharArray();
for (char aChar : chars)
{
if (branch == null)
{
return(false);
}
branch = branch.getChild(aChar);
}
return(branch != null && (branch.status == Status.WORD_END_3 || branch.status == Status.WORD_MIDDLE_2));
}
/**
* 删除一个词
*
* @param key
*/
public void remove(String key)
{
BaseNode branch = this;
char[] chars = key.toCharArray();
for (int i = 0; i < chars.length - 1; ++i)
{
if (branch == null)
{
return;
}
branch = branch.getChild(chars[i]);
}
// 最后一个字设为undefined
if (branch.addChild(new Node(chars[chars.length - 1], Status.UNDEFINED_0, value)))
{
--size;
}
}
/**
* 插入一个词
*
* @param key
* @param value
*/
public void put(String key, V value)
{
if (key.length() == 0)
{
return; // 安全起见
}
BaseNode branch = this;
char[] chars = key.toCharArray();
for (int i = 0; i < chars.length - 1; ++i)
{
// 除了最后一个字外，都是继续
branch.addChild(new Node(chars[i], Status.NOT_WORD_1, null));
branch = branch.getChild(chars[i]);
}
// 最后一个字加入时属性为end
if (branch.addChild(new Node <V>(chars[chars.length - 1], Status.WORD_END_3, value)))
{
++size; // 维护size
}
}
/**
* 前缀查询，通过字符数组来表示字符串可以优化运行速度
*
* @param chars 字符串的字符数组
* @param begin 开始的下标
* @return
*/
public LinkedList <Map.Entry <String, V> > commonPrefixSearchWithValue(char[] chars, int begin)
{
LinkedList <Map.Entry <String, V> > result = new LinkedList <Map.Entry <String, V> >();
StringBuilder sb = new StringBuilder();
BaseNode branch = this;
for (int i = begin; i < chars.length; ++i)
{
char aChar = chars[i];
branch = branch.getChild(aChar);
if (branch == null || branch.status == Status.UNDEFINED_0)
{
return(result);
}
sb.append(aChar);
if (branch.status == Status.WORD_MIDDLE_2 || branch.status == Status.WORD_END_3)
{
result.add(new AbstractMap.SimpleEntry <String, V>(sb.toString(), (V)branch.value));
}
}
return(result);
}
/**
* 前缀查询
*
* @param key 查询串
* @return 键值对
*/
public Set <Map.Entry <String, V> > prefixSearch(String key)
{
Set <Map.Entry <String, V> > entrySet = new TreeSet <Map.Entry <String, V> >();
StringBuilder sb = new StringBuilder(key.substring(0, key.length() - 1));
BaseNode branch = this;
char[] chars = key.toCharArray();
for (char aChar : chars)
{
if (branch == null)
{
return(entrySet);
}
branch = branch.getChild(aChar);
}
if (branch == null)
{
return(entrySet);
}
branch.walk(sb, entrySet);
return(entrySet);
}
