Author: ssmiweve
Date: 2008-11-30 19:38:28 +0100 (Sun, 30 Nov 2008)
New Revision: 7003
Modified:
branches/2.18/query-api/src/main/java/no/sesat/search/query/parser/AbstractClause.java
Log:
SEARCH-2837 NPE in AbstractAlternation.leftChild
alternative solution with no static synchronisation
Modified:
branches/2.18/query-api/src/main/java/no/sesat/search/query/parser/AbstractClause.java
===================================================================
---
branches/2.18/query-api/src/main/java/no/sesat/search/query/parser/AbstractClause.java
2008-11-28 22:54:37 UTC (rev 7002)
+++
branches/2.18/query-api/src/main/java/no/sesat/search/query/parser/AbstractClause.java
2008-11-30 18:38:28 UTC (rev 7003)
@@ -102,16 +102,26 @@
final String key,
final T clause,
final ReferenceMap<String,T> weakCache) {
- synchronized(weakCache) {
- T tmp = weakCache.get(key);
- if(tmp == null) {
- weakCache.put(key, clause);
- return clause;
+
+ T inUse = weakCache.get(key);
+
+ if(null == inUse){
+ // clause is not in use
+ inUse = weakCache.put(key, clause);
+
+ if(null != inUse){
+ // weakCache.get(key) is only read volatile so it may be there
was another clause already there
+ // and only the write volatile inside
weakCache.put(key.calue) sees through this small window.
+
+ // restore original clause that was in use
+ weakCache.put(key, inUse);
+
+ }else{
+ inUse = clause;
}
- else {
- return tmp;
- }
}
+
+ return inUse;
}
/**
@@ -180,18 +190,13 @@
return success;
}
- /** You must use <CODE>AbstractClause(String, Set<Predicate>,
Set<Predicate>)</CODE> instead.
- * This constructor will throw an IllegalArgumentException.
- **/
-// protected AbstractClause() {
-// throw new
IllegalArgumentException(ERR_MUST_ALWAYS_USE_ARGED_CONSTRUCTOR);
-// }
/** We need a no-argument constructor for serialization. */
protected AbstractClause() {
this.term = null;
this.knownPredicates = null;
this.possiblePredicates = null;
}
+
/**
* Create clause with the given term, known and possible predicates.
* @param term the term (query string) for this clause.
@@ -236,17 +241,28 @@
}
- /** [EMAIL PROTECTED]
- */
public void accept(final Visitor visitor) {
visitor.visit(this);
}
- /** [EMAIL PROTECTED]
- */
@Override
public String toString() {
return getClass().getSimpleName() + '[' + getTerm() + ']';
}
+ /** Provide a replicatable hashCode so the same segment inside the
ConcurrentHashMap
+ * is used for any accidently duplicate created clauses.
+ * The ConcurrentHashMap is used in this package's implementation of the
flyweight pattern.
+ *
+ * It is intended for equals(..) to use instance reference equality, ie
Object.equals(..).
+ *
+ * [EMAIL PROTECTED]
+ * @return [EMAIL PROTECTED]
+ */
+ @Override
+ public int hashCode() {
+
+ return ((getClass().hashCode() * 37) + term.hashCode()) + 17;
+ }
+
}
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