Updated master database detection algorithm

Changes made:
* updated algorithm in DBResourceManager
* Updated CachedDataSource, JdbcDBCachedDataSource
* added new unit tests

Change-Id: I4f6bbeb3839f55d183d7e762743fbc9171b63b1a
Issue-ID: CCSDK-192
Signed-off-by: Rich Tabedzki <richard.tabedzki@att.com>

8 files changed, 227 insertions, 253 deletions

diff --git a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/CachedDataSource.java b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/CachedDataSource.java
index e5eff24a5..02cce3cf1 100755
--- a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/CachedDataSource.java
+++ b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/CachedDataSource.java
@@ -47,7 +47,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * @version $Revision: 1.13 $
+ * @version $Revision: 1.14 $
  * Change Log
  * Author         Date     Comments
  * ============== ======== ====================================================
@@ -68,7 +68,7 @@ public abstract class CachedDataSource implements DataSource, SQLExecutionMonito
     protected long dataReqTimeout = 100L;
 
     private final SQLExecutionMonitor monitor;
-    protected DataSource ds = null;
+    protected final DataSource ds;
     protected String connectionName = null;
     protected boolean initialized = false;
 
@@ -85,7 +85,7 @@ public abstract class CachedDataSource implements DataSource, SQLExecutionMonito
     private boolean isDerby = false;
 
     public CachedDataSource(BaseDBConfiguration jdbcElem) throws DBConfigException {
-        configure(jdbcElem);
+        ds = configure(jdbcElem);
 
         if ("org.apache.derby.jdbc.EmbeddedDriver".equals(jdbcElem.getDriverName())) {
             isDerby = true;
@@ -93,7 +93,7 @@ public abstract class CachedDataSource implements DataSource, SQLExecutionMonito
         monitor = new SQLExecutionMonitor(this);
     }
 
-    protected abstract void configure(BaseDBConfiguration jdbcElem) throws DBConfigException;
+    protected abstract DataSource configure(BaseDBConfiguration jdbcElem) throws DBConfigException;
 
     /*
      * (non-Javadoc)
@@ -329,7 +329,6 @@ public abstract class CachedDataSource implements DataSource, SQLExecutionMonito
                 LOGGER.warn(e.getMessage());
             }
         }
-        ds = null;
         monitor.deleteObservers();
         monitor.cleanup();
     }
@@ -389,16 +388,6 @@ public abstract class CachedDataSource implements DataSource, SQLExecutionMonito
         return null;
     }
 
-    @SuppressWarnings("deprecation")
-    public void setConnectionCachingEnabled(boolean state) {
-        // if(ds != null && ds instanceof OracleDataSource)
-        // try {
-        // ((OracleDataSource)ds).setConnectionCachingEnabled(true);
-        // } catch (SQLException exc) {
-        // LOGGER.warn("", exc);
-        // }
-    }
-
     public void addObserver(Observer observer) {
         monitor.addObserver(observer);
     }
diff --git a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DBResourceManager.java b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DBResourceManager.java
index b31645d41..27c14d2a4 100755
--- a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DBResourceManager.java
+++ b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DBResourceManager.java
@@ -20,39 +20,39 @@
 
 package org.onap.ccsdk.sli.core.dblib;
 
-import org.apache.tomcat.jdbc.pool.PoolExhaustedException;
-import org.onap.ccsdk.sli.core.dblib.config.DbConfigPool;
-import org.onap.ccsdk.sli.core.dblib.factory.DBConfigFactory;
-import org.onap.ccsdk.sli.core.dblib.pm.PollingWorker;
-import org.onap.ccsdk.sli.core.dblib.pm.SQLExecutionMonitor;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import javax.sql.DataSource;
-import javax.sql.rowset.CachedRowSet;
 import java.io.PrintWriter;
 import java.sql.Connection;
 import java.sql.SQLDataException;
 import java.sql.SQLException;
 import java.sql.SQLFeatureNotSupportedException;
 import java.sql.SQLIntegrityConstraintViolationException;
+import java.sql.SQLNonTransientConnectionException;
 import java.sql.SQLSyntaxErrorException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashSet;
 import java.util.Iterator;
-import java.util.LinkedList;
 import java.util.Observable;
-import java.util.PriorityQueue;
 import java.util.Properties;
-import java.util.Queue;
 import java.util.Set;
+import java.util.SortedSet;
 import java.util.TimerTask;
 import java.util.concurrent.ConcurrentLinkedQueue;
-import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.ConcurrentSkipListSet;
+
+import javax.sql.DataSource;
+import javax.sql.rowset.CachedRowSet;
 
+import org.apache.tomcat.jdbc.pool.PoolExhaustedException;
+import org.onap.ccsdk.sli.core.dblib.config.DbConfigPool;
 import org.onap.ccsdk.sli.core.dblib.config.JDBCConfiguration;
+import org.onap.ccsdk.sli.core.dblib.factory.DBConfigFactory;
+import org.onap.ccsdk.sli.core.dblib.pm.PollingWorker;
+import org.onap.ccsdk.sli.core.dblib.pm.SQLExecutionMonitor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * @version $Revision: 1.15 $
@@ -68,31 +68,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
     transient protected long retryInterval = 10000L;
     transient boolean recoveryMode = true;
 
-    protected final AtomicBoolean dsSelector = new  AtomicBoolean();
-
-    Queue<CachedDataSource> dsQueue = new PriorityQueue<>(4, new Comparator<CachedDataSource>() {
-    @Override
-    public int compare(CachedDataSource left, CachedDataSource right) {
-        try {
-            if (left == null) {
-                return 1;
-            }
-            if (right == null) {
-                return -1;
-            }
-
-            if (!left.isSlave()) {
-                return -1;
-            }
-            if (!right.isSlave()) {
-                return 1;
-            }
-        } catch (Throwable e) {
-            LOGGER.warn("", e);
-        }
-        return 0;
-    }
-});
+    SortedSet<CachedDataSource> dsQueue = new ConcurrentSkipListSet<CachedDataSource>(new DataSourceComparator());
     protected final Set<CachedDataSource> broken = Collections.synchronizedSet(new HashSet<CachedDataSource>());
     protected final Object monitor = new Object();
     protected final Properties configProps;
@@ -174,7 +150,6 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
                 cachedDS[i].addObserver(DBResourceManager.this);
             }
 
-//                    CachedDataSource[] cachedDS = factory.initDBResourceManager(dbConfig, DBResourceManager.this, semaphore);
             DataSourceTester[] tester = new DataSourceTester[config.length];
 
             for(int i=0; i<tester.length; i++){
@@ -184,7 +159,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
             // the timeout param is set is seconds.
             long timeout = ((dbConfig.getTimeout() <= 0) ? 60L : dbConfig.getTimeout());
-            LOGGER.debug("Timeout set to " +timeout+" seconds");
+            LOGGER.debug("Timeout set to {} seconds", timeout);
             timeout *= 1000;
 
 
@@ -195,11 +170,39 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             LOGGER.warn("DBResourceManager.initWorker", exc);
         } finally {
             startTime = System.currentTimeMillis() - startTime;
-            LOGGER.info("Completed wait with "+ dsQueue.size() + " active datasource(s) in " + startTime + " ms");
+            LOGGER.info("Completed wait with {} active datasource(s) in {} ms", dsQueue.size(), startTime);
         }
     }
 
 
+    private final class DataSourceComparator implements Comparator<CachedDataSource> {
+        @Override
+        public int compare(CachedDataSource left, CachedDataSource right) {
+            if(LOGGER.isTraceEnabled())
+                LOGGER.trace("----------SORTING-------- () : ()", left.getDbConnectionName(), right.getDbConnectionName());
+            try {
+                if(left == right) {
+                    return 0;
+                }
+                if(left == null){
+                    return 1;
+                }
+                if(right == null){
+                    return -1;
+                }
+
+                if(!left.isSlave())
+                    return -1;
+                if(!right.isSlave())
+                    return 1;
+
+            } catch (Throwable e) {
+                LOGGER.warn("", e);
+            }
+            return -1;
+        }
+    }
+
     class DataSourceTester extends Thread {
 
         private final CachedDataSource ds;
@@ -224,7 +227,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
                 }
             }
             if(!slave) {
-                LOGGER.info(String.format("Adding MASTER (%s) to active queue", ds.getDbConnectionName()));
+                LOGGER.info("Adding MASTER {} to active queue", ds.getDbConnectionName());
                 try {
                     synchronized (semaphoreQ) {
                         semaphoreQ.notifyAll();
@@ -245,7 +248,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             } catch(Exception exc) {
                 LOGGER.warn("", exc);
             }
-            LOGGER.info(String.format("Thread DataSourceTester terminated %s for %s", this.getName(), ds.getDbConnectionName()));
+            LOGGER.info("Thread DataSourceTester terminated {} for {}", this.getName(), ds.getDbConnectionName());
         }
 
     }
@@ -300,7 +303,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             if(monitor.getParent() instanceof CachedDataSource)
             {
                 CachedDataSource dataSource = (CachedDataSource)monitor.getParent();
-                if(dataSource == dsQueue.peek())
+                if(dataSource == dsQueue.first())
                 {
                     if(recoveryMode && dsQueue.size() > 1){
                         handleGetConnectionException(dataSource, new Exception(data.toString()));
@@ -312,7 +315,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
     public void testForceRecovery()
     {
-        CachedDataSource active = this.dsQueue.peek();
+        CachedDataSource active = this.dsQueue.first();
         handleGetConnectionException(active, new Exception("test"));
     }
 
@@ -386,51 +389,45 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
     private CachedRowSet requestDataWithRecovery(String statement, ArrayList<Object> arguments, String preferredDS) throws SQLException {
         Throwable lastException = null;
-        CachedDataSource active = null;
 
         // test if there are any connection pools available
-        LinkedList<CachedDataSource> sources = new LinkedList<>(this.dsQueue);
-        if(sources.isEmpty()){
+        if(this.dsQueue.isEmpty()){
             LOGGER.error("Generated alarm: DBResourceManager.getData - No active DB connection pools are available.");
             throw new DBLibException("No active DB connection pools are available in RequestDataWithRecovery call.");
         }
-        if(preferredDS != null && !sources.peek().getDbConnectionName().equals(preferredDS)) {
-            Collections.reverse(sources);
-        }
-
 
         // loop through available data sources to retrieve data.
-        while(!sources.isEmpty())
+        for(int i=0; i< 2; i++)
         {
-            active = sources.peek();
+            CachedDataSource active = this.dsQueue.first();
 
             long time = System.currentTimeMillis();
             try {
                 if(!active.isFabric()) {
+                    if(this.dsQueue.size() > 1 && active.isSlave()) {
                     CachedDataSource master = findMaster();
                     if(master != null) {
                         active = master;
-                        master = null;
                     }
                 }
-                sources.remove(active);
+                }
+
                 return active.getData(statement, arguments);
             } catch(SQLDataException | SQLSyntaxErrorException | SQLIntegrityConstraintViolationException exc){
                 throw exc;
             } catch(Throwable exc){
-                lastException = exc;
-                String message = exc.getMessage();
-                if(message == null) {
-                    if(exc.getCause() != null) {
-                        message = exc.getCause().getMessage();
+                if(exc instanceof SQLException) {
+                    SQLException sqlExc = (SQLException)exc;
+                    int code = sqlExc.getErrorCode();
+                    String state = sqlExc.getSQLState();
+                    LOGGER.debug("SQLException code: {} state: {}", code, state);
+                    if("07001".equals(sqlExc.getSQLState())) {
+                        throw sqlExc;
                     }
-                    if(message == null)
-                        message = exc.getClass().getName();
                 }
-                LOGGER.error("Generated alarm: "+active.getDbConnectionName()+" - "+message);
+                lastException = exc;
+                LOGGER.error("Generated alarm: "+active.getDbConnectionName(), exc);
                 handleGetConnectionException(active, exc);
-                if(sources.contains(active))
-                    sources.remove(active);
             } finally {
                 if(LOGGER.isDebugEnabled()){
                     time = System.currentTimeMillis() - time;
@@ -462,14 +459,17 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             LOGGER.error("Generated alarm: DBResourceManager.getData - No active DB connection pools are available.");
             throw new DBLibException("No active DB connection pools are available in RequestDataNoRecovery call.");
         }
-        CachedDataSource active = this.dsQueue.peek();
+        CachedDataSource active = this.dsQueue.first();
         long time = System.currentTimeMillis();
         try {
             if(!active.isFabric()) {
+                if(this.dsQueue.size() > 1 && active.isSlave()) {
                 CachedDataSource master = findMaster();
-                if(master != null)
+                    if(master != null) {
                     active = master;
             }
+                }
+            }
             return active.getData(statement, arguments);
 //        } catch(SQLDataException exc){
 //            throw exc;
@@ -508,17 +508,21 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
         return writeDataNoRecovery(statement, newList, preferredDS);
     }
 
-    CachedDataSource findMaster() throws PoolExhaustedException {
-        CachedDataSource master = null;
-        CachedDataSource[] dss = this.dsQueue.toArray(new CachedDataSource[0]);
-        for(int i=0; i<dss.length; i++) {
-            if(!dss[i].isSlave()) {
-                master = dss[i];
-                if(i != 0) {
-                    dsQueue.remove(master);
-                    dsQueue.add(master);
+    synchronized CachedDataSource findMaster() throws SQLException {
+        final CachedDataSource[] clone = this.dsQueue.toArray(new CachedDataSource[0]);
+
+        for(final CachedDataSource  dss : clone) {
+            if(!dss.isSlave()) {
+                final CachedDataSource first = this.dsQueue.first();
+                if(first != dss) {
+                    if(LOGGER.isDebugEnabled())
+                        LOGGER.debug("----------REODRERING--------");
+                    dsQueue.clear();
+                    if(!dsQueue.addAll(Arrays.asList(clone))) {
+                        LOGGER.error("Failed adding datasources");
+                }
                 }
-                return master;
+                return  dss;
             }
         }
         LOGGER.warn("MASTER not found.");
@@ -534,17 +538,19 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
         boolean initialRequest = true;
         boolean retryAllowed = true;
-        CachedDataSource active = this.dsQueue.peek();
+        CachedDataSource active = this.dsQueue.first();
         long time = System.currentTimeMillis();
         while(initialRequest) {
             initialRequest = false;
             try {
                 if(!active.isFabric()) {
+                    if(this.dsQueue.size() > 1 && active.isSlave()) {
                     CachedDataSource master = findMaster();
                     if(master != null) {
                         active = master;
                     }
                 }
+                }
 
                 return active.writeData(statement, arguments);
             } catch(Throwable exc){
@@ -557,8 +563,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
                     // handle read-only exception
                     if(sqlExc.getErrorCode() == 1290 && "HY000".equals(sqlExc.getSQLState())) {
                         LOGGER.warn("retrying due to: " + sqlExc.getMessage());
-                        dsQueue.remove(active);
-                        dsQueue.add(active);
+                        this.findMaster();
                         if(retryAllowed){
                             retryAllowed = false;
                             initialRequest = true;
@@ -604,10 +609,15 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
         }
 
         try {
-            active = dsQueue.peek();
-            CachedDataSource tmpActive = findMaster();
-            if(tmpActive != null) {
-                active = tmpActive;
+            active = dsQueue.first();
+
+            if(!active.isFabric()) {
+                if(this.dsQueue.size() > 1 && active.isSlave()) {
+                    CachedDataSource master = findMaster();
+                    if(master != null) {
+                        active = master;
+                    }
+                }
             }
             return new DBLibConnection(active.getConnection(), active);
         } catch(javax.sql.rowset.spi.SyncFactoryException exc){
@@ -616,6 +626,8 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             lastException = exc;
         } catch(PoolExhaustedException exc) {
             throw new NoAvailableConnectionsException(exc);
+        } catch(SQLNonTransientConnectionException exc){
+            throw new NoAvailableConnectionsException(exc);
         } catch(Exception exc){
             lastException = exc;
             if(recoveryMode){
@@ -667,10 +679,14 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
 
         try {
-            active = dsQueue.peek();
-            CachedDataSource tmpActive = findMaster();
-            if(tmpActive != null) {
-                active = tmpActive;
+            active = dsQueue.first();
+            if(!active.isFabric()) {
+                if(this.dsQueue.size() > 1 && active.isSlave()) {
+                    CachedDataSource master = findMaster();
+                    if(master != null) {
+                        active = master;
+                    }
+                }
             }
             return active.getConnection(username, password);
         } catch(Throwable exc){
@@ -691,7 +707,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
         throw new DBLibException("No connections available in DBResourceManager in GetConnection call.");
     }
 
-    private void handleGetConnectionException(CachedDataSource source, Throwable exc) {
+    private void handleGetConnectionException(final CachedDataSource source, Throwable exc) {
         try {
             if(!source.canTakeOffLine())
             {
@@ -715,7 +731,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
             {
                 if(!dsQueue.isEmpty())
                 {
-                    LOGGER.warn("DB DataSource <" + dsQueue.peek().getDbConnectionName()    + "> became active");
+                    LOGGER.warn("DB DataSource <" + dsQueue.first().getDbConnectionName()    + "> became active");
                 }
             }
         } catch (Exception e) {
@@ -749,28 +765,28 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
 
     @Override
     public PrintWriter getLogWriter() throws SQLException {
-        return this.dsQueue.peek().getLogWriter();
+        return this.dsQueue.first().getLogWriter();
     }
 
     @Override
     public int getLoginTimeout() throws SQLException {
-        return this.dsQueue.peek().getLoginTimeout();
+        return this.dsQueue.first().getLoginTimeout();
     }
 
     @Override
     public void setLogWriter(PrintWriter out) throws SQLException {
-        this.dsQueue.peek().setLogWriter(out);
+        this.dsQueue.first().setLogWriter(out);
     }
 
     @Override
     public void setLoginTimeout(int seconds) throws SQLException {
-        this.dsQueue.peek().setLoginTimeout(seconds);
+        this.dsQueue.first().setLoginTimeout(seconds);
     }
 
     public void displayState(){
         if(LOGGER.isDebugEnabled()){
             LOGGER.debug("POOLS : Active = "+dsQueue.size() + ";\t Broken = "+broken.size());
-            CachedDataSource current = dsQueue.peek();
+            CachedDataSource current = dsQueue.first();
             if(current != null) {
                 LOGGER.debug("POOL : Active name = \'"+current.getDbConnectionName()+ "\'");
             }
@@ -811,7 +827,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
                     buffer.append("<td>in recovery</td>");
                 }
                 if (dsQueue.contains(list.get(i))) {
-                    if (dsQueue.peek() == list.get(i))
+                    if (dsQueue.first() == list.get(i))
                         buffer.append("<td>active</td>");
                     else
                         buffer.append("<td>standby</td>");
@@ -827,7 +843,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
                     buffer.append("in recovery");
                 } else
                 if (dsQueue.contains(list.get(i))) {
-                    if (dsQueue.peek() == list.get(i))
+                    if (dsQueue.first() == list.get(i))
                         buffer.append("active");
                     else
                         buffer.append("standby");
@@ -859,7 +875,7 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
     }
 
     public void test(){
-        CachedDataSource obj = dsQueue.peek();
+        CachedDataSource obj = dsQueue.first();
         Exception ption = new Exception();
         try {
             for(int i=0; i<5; i++)
@@ -871,77 +887,16 @@ public class DBResourceManager implements DataSource, DataAccessor, DBResourceOb
         }
     }
 
-    public String getPreferredDSName(){
-        if(isActive()){
-            return getPreferredDataSourceName(dsSelector);
-        }
-        return "";
-    }
-
-    public String getPreferredDataSourceName(AtomicBoolean flipper) {
-
-        LinkedList<CachedDataSource> snapshot = new LinkedList<>(dsQueue);
-        if(snapshot.size() > 1){
-            CachedDataSource first = snapshot.getFirst();
-            CachedDataSource last = snapshot.getLast();
-
-            int delta = first.getMonitor().getProcessedConnectionsCount() - last.getMonitor().getProcessedConnectionsCount();
-            if(delta < 0) {
-                flipper.set(false);
-            } else if(delta > 0) {
-                flipper.set(true);
-            } else {
-                // check the last value and return !last
-                flipper.getAndSet(!flipper.get());
-            }
-
-            if (flipper.get())
-                Collections.reverse(snapshot);
-        }
-        return snapshot.peek().getDbConnectionName();
-    }
-
     @Override
     public java.util.logging.Logger getParentLogger()
             throws SQLFeatureNotSupportedException {
         return null;
     }
 
-    public String getMasterName() {
-        if(isActive()){
-            return getMasterDataSourceName(dsSelector);
-        }
-        return "";
-    }
-
-
-    private String getMasterDataSourceName(AtomicBoolean flipper) {
-
-        LinkedList<CachedDataSource> snapshot = new LinkedList<>(dsQueue);
-        if(snapshot.size() > 1){
-            CachedDataSource first = snapshot.getFirst();
-            CachedDataSource last = snapshot.getLast();
-
-            int delta = first.getMonitor().getProcessedConnectionsCount() - last.getMonitor().getProcessedConnectionsCount();
-            if(delta < 0) {
-                flipper.set(false);
-            } else if(delta > 0) {
-                flipper.set(true);
-            } else {
-                // check the last value and return !last
-                flipper.getAndSet(!flipper.get());
-            }
-
-            if (flipper.get())
-                Collections.reverse(snapshot);
-        }
-        return snapshot.peek().getDbConnectionName();
-    }
-
     class RemindTask extends TimerTask {
         @Override
         public void run() {
-            CachedDataSource ds = dsQueue.peek();
+            CachedDataSource ds = dsQueue.first();
             if(ds != null)
                 ds.getPoolInfo(false);
         }
diff --git a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DataAccessor.java b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DataAccessor.java
index fdfb47bca..93d8b6bf5 100644
--- a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DataAccessor.java
+++ b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/DataAccessor.java
@@ -25,6 +25,7 @@ import java.util.ArrayList;
 
 import javax.sql.rowset.CachedRowSet;
 
+@FunctionalInterface
 public interface DataAccessor {
 
     CachedRowSet getData(String statement, ArrayList<String> arguments, String preferredDS)
diff --git a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/TerminatingCachedDataSource.java b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/TerminatingCachedDataSource.java
index b4d1ef679..92b31470e 100644..100755
--- a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/TerminatingCachedDataSource.java
+++ b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/TerminatingCachedDataSource.java
@@ -22,71 +22,71 @@ package org.onap.ccsdk.sli.core.dblib;
 
 import java.sql.SQLFeatureNotSupportedException;
 import java.util.logging.Logger;
-
+import javax.sql.DataSource;
 import org.onap.ccsdk.sli.core.dblib.config.BaseDBConfiguration;
 import org.onap.ccsdk.sli.core.dblib.pm.SQLExecutionMonitorObserver;
 
 
 public class TerminatingCachedDataSource extends CachedDataSource implements SQLExecutionMonitorObserver {
 
-	public TerminatingCachedDataSource(BaseDBConfiguration jdbcElem) throws DBConfigException {
-		super(jdbcElem);
-	}
-
-	@Override
-	protected void configure(BaseDBConfiguration jdbcElem) throws DBConfigException {
-		// no action
-	}
-
-	@Override
-	public long getInterval() {
-		return 1000;
-	}
-
-	@Override
-	public long getInitialDelay() {
-		return 1000;
-	}
-
-	@Override
-	public long getExpectedCompletionTime() {
-		return 50;
-	}
-
-	@Override
-	public void setExpectedCompletionTime(long value) {
-		
-	}
-
-	@Override
-	public void setInterval(long value) {
-		
-	}
-
-	@Override
-	public void setInitialDelay(long value) {
-		
-	}
-
-	@Override
-	public long getUnprocessedFailoverThreshold() {
-		return 3;
-	}
-
-	@Override
-	public void setUnprocessedFailoverThreshold(long value) {
-		
-	}
-	
-	public int compareTo(CachedDataSource ods)
-	{
-		return 0;
-	}
-
-	@Override
-	public Logger getParentLogger() throws SQLFeatureNotSupportedException {
-		// TODO Auto-generated method stub
-		return null;
-	}
+    public TerminatingCachedDataSource(BaseDBConfiguration jdbcElem) throws DBConfigException {
+        super(jdbcElem);
+    }
+
+    @Override
+    protected DataSource configure(BaseDBConfiguration jdbcElem) throws DBConfigException {
+        return null;
+    }
+
+    @Override
+    public long getInterval() {
+        return 1000;
+    }
+
+    @Override
+    public long getInitialDelay() {
+        return 1000;
+    }
+
+    @Override
+    public long getExpectedCompletionTime() {
+        return 50;
+    }
+
+    @Override
+    public void setExpectedCompletionTime(long value) {
+
+    }
+
+    @Override
+    public void setInterval(long value) {
+
+    }
+
+    @Override
+    public void setInitialDelay(long value) {
+
+    }
+
+    @Override
+    public long getUnprocessedFailoverThreshold() {
+        return 3;
+    }
+
+    @Override
+    public void setUnprocessedFailoverThreshold(long value) {
+
+    }
+
+    public int compareTo(CachedDataSource ods)
+    {
+        return 0;
+    }
+
+    @Override
+    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
+        // TODO Auto-generated method stub
+        return null;
+    }
 
 }
diff --git a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/jdbc/JdbcDBCachedDataSource.java b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/jdbc/JdbcDBCachedDataSource.java
index ca16834c4..a6582b9e7 100755
--- a/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/jdbc/JdbcDBCachedDataSource.java
+++ b/dblib/provider/src/main/java/org/onap/ccsdk/sli/core/dblib/jdbc/JdbcDBCachedDataSource.java
@@ -53,7 +53,7 @@ public class JdbcDBCachedDataSource extends CachedDataSource {
     }
 
     @Override
-    protected void configure(BaseDBConfiguration xmlElem) throws DBConfigException {
+    protected DataSource configure(BaseDBConfiguration xmlElem) throws DBConfigException {
         BaseDBConfiguration jdbcConfig = xmlElem;
         if (jdbcConfig.getConnTimeout() > 0) {
             this.connReqTimeout = jdbcConfig.getConnTimeout();
@@ -90,23 +90,23 @@ public class JdbcDBCachedDataSource extends CachedDataSource {
         minLimit = jdbcConfig.getDbMinLimit();
 //        if (minLimit == null)
 //        {
-//        	String errorMsg =  "Invalid XML contents: JDBC Connection missing minLimit attribute";
-//        	LOGGER.error(AS_CONF_ERROR + errorMsg);
-//        	throw new DBConfigException(errorMsg);
+//            String errorMsg =  "Invalid XML contents: JDBC Connection missing minLimit attribute";
+//            LOGGER.error(AS_CONF_ERROR + errorMsg);
+//            throw new DBConfigException(errorMsg);
 //        }
         maxLimit = jdbcConfig.getDbMaxLimit();
 //        if (maxLimit == null)
 //        {
-//        	String errorMsg =  "Invalid XML contents: JDBC Connection missing maxLimit attribute";
-//        	LOGGER.error(AS_CONF_ERROR + errorMsg);
-//        	throw new DBConfigException(errorMsg);
+//            String errorMsg =  "Invalid XML contents: JDBC Connection missing maxLimit attribute";
+//            LOGGER.error(AS_CONF_ERROR + errorMsg);
+//            throw new DBConfigException(errorMsg);
 //        }
         initialLimit = jdbcConfig.getDbInitialLimit();
 //        if (initialLimit == null)
 //        {
-//        	String errorMsg =  "Invalid XML contents: JDBC Connection missing initialLimit attribute";
-//        	LOGGER.error(AS_CONF_ERROR + errorMsg);
-//        	throw new DBConfigException(errorMsg);
+//            String errorMsg =  "Invalid XML contents: JDBC Connection missing initialLimit attribute";
+//            LOGGER.error(AS_CONF_ERROR + errorMsg);
+//            throw new DBConfigException(errorMsg);
 //        }
 
         dbUrl = jdbcConfig.getDbUrl();
@@ -142,20 +142,19 @@ public class JdbcDBCachedDataSource extends CachedDataSource {
             p.setJdbcInterceptors("org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;"
                 + "org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer");
 
-            DataSource dataSource = new DataSource(p);
+            final DataSource dataSource = new DataSource(p);
 
             synchronized (this) {
-                this.ds = dataSource;
-
                 initialized = true;
+            }
                 LOGGER.info(String.format("JdbcDBCachedDataSource <%s> configured successfully. Using URL: %s",
                     dbConnectionName, dbUrl));
-            }
+            return dataSource;
         } catch (Exception exc) {
             initialized = false;
             LOGGER.error(String.format("AS_CONF_ERROR: Failed to initialize MySQLCachedDataSource <%s>. Reason: %s",
                 dbConnectionName, exc.getMessage()));
-//    		throw new DBConfigException(e.getMessage());
+            return null;
         }
     }
 
diff --git a/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/DBLibExceptionTest.java b/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/DBLibExceptionTest.java
new file mode 100644
index 000000000..cab24042c
--- /dev/null
+++ b/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/DBLibExceptionTest.java
@@ -0,0 +1,14 @@
+package org.onap.ccsdk.sli.core.dblib;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class DBLibExceptionTest {
+
+    @Test
+    public void testDBLibException() {
+        assertNotNull(new DBLibException("test"));
+    }
+
+}
diff --git a/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/NoAvailableConnectionsExceptionTest.java b/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/NoAvailableConnectionsExceptionTest.java
new file mode 100644
index 000000000..2fdacb922
--- /dev/null
+++ b/dblib/provider/src/test/java/org/onap/ccsdk/sli/core/dblib/NoAvailableConnectionsExceptionTest.java
@@ -0,0 +1,16 @@
+package org.onap.ccsdk.sli.core.dblib;
+
+import static org.junit.Assert.*;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class NoAvailableConnectionsExceptionTest {
+
+    @Test
+    public void testNoAvailableConnectionsException() {
+        assertNotNull(new NoAvailableConnectionsException(new Exception("test")));
+    }
+
+}
diff --git a/sli/common/src/main/antlr4/org/onap/ccsdk/sli/core/sli/ExprGrammar.g4 b/sli/common/src/main/antlr4/org/onap/ccsdk/sli/core/sli/ExprGrammar.g4
index 1b026bb1a..42563168c 100755
--- a/sli/common/src/main/antlr4/org/onap/ccsdk/sli/core/sli/ExprGrammar.g4
+++ b/sli/common/src/main/antlr4/org/onap/ccsdk/sli/core/sli/ExprGrammar.g4
@@ -16,7 +16,7 @@ MULTOP : '/' | '*';
 
 NUMBER : ('0'..'9')+;
 
-STRING : '\'' ~[\']* '\'';
+STRING : '\'' ~[']* '\'';
 
 IDENTIFIER : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_'|'-')*;