Remove all expired entries in SessionCache on validator init (#846)

+ fix typo in JsonParserBase

Co-authored-by: dotasek <david.otasek@smilecdr.com>

org.hl7.fhir.dstu2/src/main/java/org/hl7/fhir/dstu2/formats/JsonParserBase.java

@@ -1,33 +1,33 @@
 package org.hl7.fhir.dstu2.formats;
 
-/*
-  Copyright (c) 2011+, HL7, Inc.
-  All rights reserved.
-  
-  Redistribution and use in source and binary forms, with or without modification, 
-  are permitted provided that the following conditions are met:
-    
-   * Redistributions of source code must retain the above copyright notice, this 
-     list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above copyright notice, 
-     this list of conditions and the following disclaimer in the documentation 
-     and/or other materials provided with the distribution.
-   * Neither the name of HL7 nor the names of its contributors may be used to 
-     endorse or promote products derived from this software without specific 
-     prior written permission.
-  
-  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
-  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
-  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
-  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
-  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
-  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
-  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
-  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
-  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
-  POSSIBILITY OF SUCH DAMAGE.
-  
- */
+/*
+  Copyright (c) 2011+, HL7, Inc.
+  All rights reserved.
+  
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+    
+   * Redistributions of source code must retain the above copyright notice, this 
+     list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above copyright notice, 
+     this list of conditions and the following disclaimer in the documentation 
+     and/or other materials provided with the distribution.
+   * Neither the name of HL7 nor the names of its contributors may be used to 
+     endorse or promote products derived from this software without specific 
+     prior written permission.
+  
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 
+  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 
+  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 
+  IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 
+  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
+  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
+  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
+  POSSIBILITY OF SUCH DAMAGE.
+  
+ */
 
 
 /*
@@ -122,7 +122,7 @@ public abstract class JsonParserBase extends ParserBase implements IParser {
   }
 
   /**
-   * parse xml that is known to be a resource, and that has already been read into a JSON object  
+   * Parse JSON that is known to be a resource, and that has already been read into a JSON object
    * @throws IOException 
    * @throws FHIRFormatError 
    */

org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/SessionCache.java

@@ -59,6 +59,19 @@ public class SessionCache {
     return sessionId;
   }
 
+  /**
+   * When called, this actively checks the cache for expired entries and removes
+   * them.
+   */
+  public void removeExpiredSessions() {
+    /*
+    The PassiveExpiringMap will remove entries when accessing the mapped value
+    for a key, OR when invoking methods that involve accessing the entire map
+    contents. So, we call keySet below to force removal of all expired entries.
+    * */
+    cachedSessions.keySet();
+  }
+
   /**
    * Checks if the passed in {@link String} id exists in the set of stored session id.
    * @param sessionId The {@link String} id to search for.

org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/cli/services/ValidationService.java

@@ -328,6 +328,7 @@ public class ValidationService {
 
   public String initializeValidator(CliContext cliContext, String definitions, TimeTracker tt, String sessionId) throws Exception {
     tt.milestone();
+    sessionCache.removeExpiredSessions();
     if (!sessionCache.sessionExists(sessionId)) {
       if (sessionId != null) {
         System.out.println("No such cached session exists for session id " + sessionId + ", re-instantiating validator.");

org.hl7.fhir.validation/src/test/java/org/hl7/fhir/validation/cli/services/SessionCacheTest.java

@@ -48,4 +48,17 @@ class SessionCacheTest {
     SessionCache cache = new SessionCache();
     Assertions.assertFalse(cache.sessionExists(null));
   }
+
+  @Test
+  @DisplayName("test that explicit removeExiredSessions works")
+  void testRemoveExpiredSessions() throws InterruptedException, IOException {
+    final long EXPIRE_TIME = 5L;
+    SessionCache cache = new SessionCache(EXPIRE_TIME, TimeUnit.SECONDS);
+    ValidationEngine testEngine = new ValidationEngine.ValidationEngineBuilder().fromNothing();
+    String sessionId = cache.cacheSession(testEngine);
+    Assertions.assertTrue(cache.sessionExists(sessionId));
+    TimeUnit.SECONDS.sleep(EXPIRE_TIME + 1L);
+    cache.removeExpiredSessions();
+    Assertions.assertTrue(cache.getSessionIds().isEmpty());
+  }
 }