/**
* Retrieves Strings corresponding to all valid _transition paths from a given node that satisfy a
* given condition.
*
* @param strHashSet a HashSet of Strings to contain all those in the MDAG satisfying {@code
* searchCondition} with {@code conditionString}
* @param searchCondition the SearchCondition enum field describing the type of relationship that
* Strings contained in the MDAG must have with {@code conditionString} in order to be
* included in the result set
* @param searchConditionString the String that all Strings in the MDAG must be related with in
* the fashion denoted by {@code searchCondition} in order to be included in the result set
* @param prefixString the String corresponding to the currently traversed _transition path
* @param node an int denoting the starting index of a SimpleMDAGNode's _transition set in
* mdagDataArray
*/
private void getStrings(
HashSet<String> strHashSet,
SearchCondition searchCondition,
String searchConditionString,
String prefixString,
SimpleMDAGNode node) {
int transitionSetBegin = node.getTransitionSetBeginIndex();
int onePastTransitionSetEnd = transitionSetBegin + node.getOutgoingTransitionSetSize();
// Traverse all the valid _transition paths beginning from each _transition in
// transitionTreeMap, inserting the
// corresponding Strings in to strHashSet that have the relationship with conditionString
// denoted by searchCondition
for (int i = transitionSetBegin; i < onePastTransitionSetEnd; i++) {
SimpleMDAGNode currentNode = mdagDataArray[i];
String newPrefixString = prefixString + currentNode.getLetter();
if (currentNode.isAcceptNode()
&& searchCondition.satisfiesCondition(newPrefixString, searchConditionString))
strHashSet.add(newPrefixString);
// Recursively call this to traverse all the valid _transition paths from currentNode
getStrings(strHashSet, searchCondition, searchConditionString, newPrefixString, currentNode);
}
/////
}
/**
* 是否包含<br>
* Determines whether a String is present in the MDAG.
*
* @param str the String to be searched for
* @return true if {@code str} is present in the MDAG, and false otherwise
*/
public boolean contains(String str) {
if (sourceNode != null) // if the MDAG hasn't been simplified
{
MDAGNode targetNode = sourceNode.transition(str.toCharArray());
return (targetNode != null && targetNode.isAcceptNode());
} else {
SimpleMDAGNode targetNode = simplifiedSourceNode.transition(mdagDataArray, str.toCharArray());
return (targetNode != null && targetNode.isAcceptNode());
}
}
@Override
public void save(DataOutputStream out) throws Exception {
simplify();
out.writeInt(charTreeSet.size());
for (Character character : charTreeSet) {
out.writeChar(character);
}
simplifiedSourceNode.save(out);
out.writeInt(mdagDataArray.length);
for (SimpleMDAGNode simpleMDAGNode : mdagDataArray) {
simpleMDAGNode.save(out);
}
}
/**
* 前缀查询<br>
* Retrieves all the Strings in the MDAG that begin with a given String.
*
* @param prefixStr a String that is the prefix for all the desired Strings
* @return a HashSet containing all the Strings present in the MDAG that begin with {@code
* prefixString}
*/
public HashSet<String> getStringsStartingWith(String prefixStr) {
HashSet<String> strHashSet = new HashSet<String>();
if (sourceNode != null) // if the MDAG hasn't been simplified
{
MDAGNode originNode =
sourceNode.transition(
prefixStr); // attempt to _transition down the path denoted by prefixStr
if (originNode
!= null) // if there a _transition path corresponding to prefixString (one or more stored
// Strings begin with prefixString)
{
if (originNode.isAcceptNode()) strHashSet.add(prefixStr);
getStrings(
strHashSet,
SearchCondition.PREFIX_SEARCH_CONDITION,
prefixStr,
prefixStr,
originNode
.getOutgoingTransitions()); // retrieve all Strings that extend the _transition path
// denoted by prefixStr
}
} else {
SimpleMDAGNode originNode =
SimpleMDAGNode.traverseMDAG(
mdagDataArray,
simplifiedSourceNode,
prefixStr); // attempt to _transition down the path denoted by prefixStr
if (originNode
!= null) // if there a _transition path corresponding to prefixString (one or more stored
// Strings begin with prefixStr)
{
if (originNode.isAcceptNode()) strHashSet.add(prefixStr);
getStrings(
strHashSet,
SearchCondition.PREFIX_SEARCH_CONDITION,
prefixStr,
prefixStr,
originNode); // retrieve all Strings that extend the _transition path denoted by
// prefixString
}
}
return strHashSet;
}
@Override
public boolean load(ByteArray byteArray) {
int length = byteArray.nextInt();
for (int i = 0; i < length; ++i) {
charTreeSet.add(byteArray.nextChar());
}
simplifiedSourceNode = new SimpleMDAGNode();
simplifiedSourceNode.load(byteArray);
length = byteArray.nextInt();
mdagDataArray = new SimpleMDAGNode[length];
for (int i = 0; i < length; ++i) {
mdagDataArray[i] = new SimpleMDAGNode();
mdagDataArray[i].load(byteArray);
}
sourceNode = null;
return true;
}
/**
* 递归创建节点<br>
*
* @param current 当前简易节点
* @param fromIndex 起点下标
* @param toNodeArray 终点数组
* @param fromNodeArray 起点数组，它们两个按照下标一一对应
*/
private void createMDAGNode(
SimpleMDAGNode current, int fromIndex, MDAGNode[] toNodeArray, MDAGNode[] fromNodeArray) {
MDAGNode from = (fromIndex == -1 ? sourceNode : toNodeArray[fromIndex]);
int transitionSetBegin = current.getTransitionSetBeginIndex();
int onePastTransitionSetEnd = transitionSetBegin + current.getOutgoingTransitionSetSize();
for (int i = transitionSetBegin; i < onePastTransitionSetEnd; i++) {
SimpleMDAGNode targetNode = mdagDataArray[i];
if (toNodeArray[i] != null) {
fromNodeArray[fromIndex].addOutgoingTransition(current.getLetter(), fromNodeArray[i]);
toNodeArray[fromIndex] = fromNodeArray[i];
continue;
}
toNodeArray[i] =
from.addOutgoingTransition(targetNode.getLetter(), targetNode.isAcceptNode());
fromNodeArray[i] = from;
createMDAGNode(targetNode, i, toNodeArray, fromNodeArray);
}
}