Refactoring.

src/main/java/org/apache/ibatis/datasource/pooled/PooledDataSource.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,6 +15,11 @@
  */
 package org.apache.ibatis.datasource.pooled;
 
+import org.apache.ibatis.datasource.unpooled.UnpooledDataSource;
+import org.apache.ibatis.logging.Log;
+import org.apache.ibatis.logging.LogFactory;
+
+import javax.sql.DataSource;
 import java.io.PrintWriter;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Proxy;
@@ -25,12 +30,6 @@
 import java.util.Properties;
 import java.util.logging.Logger;
 
-import javax.sql.DataSource;
-
-import org.apache.ibatis.datasource.unpooled.UnpooledDataSource;
-import org.apache.ibatis.logging.Log;
-import org.apache.ibatis.logging.LogFactory;
-
 /**
  * This is a simple, synchronous, thread-safe database connection pool.
  *
@@ -439,32 +438,7 @@ private PooledConnection popConnection(String username, String password) throws
             long longestCheckoutTime = oldestActiveConnection.getCheckoutTime();
             if (longestCheckoutTime > poolMaximumCheckoutTime) {
               // Can claim overdue connection
-              state.claimedOverdueConnectionCount++;
-              state.accumulatedCheckoutTimeOfOverdueConnections += longestCheckoutTime;
-              state.accumulatedCheckoutTime += longestCheckoutTime;
-              state.activeConnections.remove(oldestActiveConnection);
-              if (!oldestActiveConnection.getRealConnection().getAutoCommit()) {
-                try {
-                  oldestActiveConnection.getRealConnection().rollback();
-                } catch (SQLException e) {
-                  /*
-                     Just log a message for debug and continue to execute the following
-                     statement like nothing happened.
-                     Wrap the bad connection with a new PooledConnection, this will help
-                     to not interrupt current executing thread and give current thread a
-                     chance to join the next competition for another valid/good database
-                     connection. At the end of this loop, bad {@link @conn} will be set as null.
-                   */
-                  log.debug("Bad connection. Could not roll back");
-                }
-              }
-              conn = new PooledConnection(oldestActiveConnection.getRealConnection(), this);
-              conn.setCreatedTimestamp(oldestActiveConnection.getCreatedTimestamp());
-              conn.setLastUsedTimestamp(oldestActiveConnection.getLastUsedTimestamp());
-              oldestActiveConnection.invalidate();
-              if (log.isDebugEnabled()) {
-                log.debug("Claimed overdue connection " + conn.getRealHashCode() + ".");
-              }
+              conn = claimOverdueConnection(oldestActiveConnection, longestCheckoutTime);
             } else {
               // Must wait
               try {
@@ -525,6 +499,37 @@ private PooledConnection popConnection(String username, String password) throws
     return conn;
   }
 
+  private PooledConnection claimOverdueConnection(PooledConnection oldestActiveConnection, long longestCheckoutTime) throws SQLException {
+    PooledConnection conn;
+    state.claimedOverdueConnectionCount++;
+    state.accumulatedCheckoutTimeOfOverdueConnections += longestCheckoutTime;
+    state.accumulatedCheckoutTime += longestCheckoutTime;
+    state.activeConnections.remove(oldestActiveConnection);
+    if (!oldestActiveConnection.getRealConnection().getAutoCommit()) {
+      try {
+        oldestActiveConnection.getRealConnection().rollback();
+      } catch (SQLException e) {
+        /*
+           Just log a message for debug and continue to execute the following
+           statement like nothing happened.
+           Wrap the bad connection with a new PooledConnection, this will help
+           to not interrupt current executing thread and give current thread a
+           chance to join the next competition for another valid/good database
+           connection. At the end of this loop, bad {@link @conn} will be set as null.
+         */
+        log.debug("Bad connection. Could not roll back");
+      }
+    }
+    conn = new PooledConnection(oldestActiveConnection.getRealConnection(), this);
+    conn.setCreatedTimestamp(oldestActiveConnection.getCreatedTimestamp());
+    conn.setLastUsedTimestamp(oldestActiveConnection.getLastUsedTimestamp());
+    oldestActiveConnection.invalidate();
+    if (log.isDebugEnabled()) {
+      log.debug("Claimed overdue connection " + conn.getRealHashCode() + ".");
+    }
+    return conn;
+  }
+
   /**
    * Method to check to see if a connection is still usable
    *

src/main/java/org/apache/ibatis/executor/loader/AbstractSerialStateHolder.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,25 +15,15 @@
  */
 package org.apache.ibatis.executor.loader;
 
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.Externalizable;
-import java.io.IOException;
-import java.io.InvalidClassException;
-import java.io.ObjectInput;
-import java.io.ObjectInputStream;
-import java.io.ObjectOutput;
-import java.io.ObjectOutputStream;
-import java.io.ObjectStreamException;
-import java.io.StreamCorruptedException;
+import org.apache.ibatis.io.SerialFilterChecker;
+import org.apache.ibatis.reflection.factory.ObjectFactory;
+
+import java.io.*;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
-import org.apache.ibatis.io.SerialFilterChecker;
-import org.apache.ibatis.reflection.factory.ObjectFactory;
-
 /**
  * @author Eduardo Macarron
  * @author Franta Mejta
@@ -68,21 +58,21 @@ public AbstractSerialStateHolder(
   @Override
   public final void writeExternal(final ObjectOutput out) throws IOException {
     boolean firstRound = false;
-    final ByteArrayOutputStream baos = new ByteArrayOutputStream();
-    ObjectOutputStream os = stream.get();
-    if (os == null) {
-      os = new ObjectOutputStream(baos);
+    final ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
+    ObjectOutputStream objectOutputStream = stream.get();
+    if (objectOutputStream == null) {
+      objectOutputStream = new ObjectOutputStream(byteArrayOutputStream);
       firstRound = true;
-      stream.set(os);
+      stream.set(objectOutputStream);
     }
 
-    os.writeObject(this.userBean);
-    os.writeObject(this.unloadedProperties);
-    os.writeObject(this.objectFactory);
-    os.writeObject(this.constructorArgTypes);
-    os.writeObject(this.constructorArgs);
+    objectOutputStream.writeObject(this.userBean);
+    objectOutputStream.writeObject(this.unloadedProperties);
+    objectOutputStream.writeObject(this.objectFactory);
+    objectOutputStream.writeObject(this.constructorArgTypes);
+    objectOutputStream.writeObject(this.constructorArgs);
 
-    final byte[] bytes = baos.toByteArray();
+    final byte[] bytes = byteArrayOutputStream.toByteArray();
     out.writeObject(bytes);
 
     if (firstRound) {

src/main/java/org/apache/ibatis/reflection/MetaObject.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,29 +15,32 @@
  */
 package org.apache.ibatis.reflection;
 
+import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
+import org.apache.ibatis.reflection.factory.ObjectFactory;
+import org.apache.ibatis.reflection.property.PropertyTokenizer;
+import org.apache.ibatis.reflection.wrapper.*;
+
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 
-import org.apache.ibatis.reflection.factory.ObjectFactory;
-import org.apache.ibatis.reflection.property.PropertyTokenizer;
-import org.apache.ibatis.reflection.wrapper.BeanWrapper;
-import org.apache.ibatis.reflection.wrapper.CollectionWrapper;
-import org.apache.ibatis.reflection.wrapper.MapWrapper;
-import org.apache.ibatis.reflection.wrapper.ObjectWrapper;
-import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
-
 /**
  * @author Clinton Begin
  */
 public class MetaObject {
 
+  public static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();
+  public static final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory();
+  public static final MetaObject NULL_META_OBJECT = forObject(new NullObject(), DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());
   private final Object originalObject;
   private final ObjectWrapper objectWrapper;
   private final ObjectFactory objectFactory;
   private final ObjectWrapperFactory objectWrapperFactory;
   private final ReflectorFactory reflectorFactory;
 
+  private static class NullObject {
+  }
+
   private MetaObject(Object object, ObjectFactory objectFactory, ObjectWrapperFactory objectWrapperFactory, ReflectorFactory reflectorFactory) {
     this.originalObject = object;
     this.objectFactory = objectFactory;
@@ -59,7 +62,7 @@ private MetaObject(Object object, ObjectFactory objectFactory, ObjectWrapperFact
 
   public static MetaObject forObject(Object object, ObjectFactory objectFactory, ObjectWrapperFactory objectWrapperFactory, ReflectorFactory reflectorFactory) {
     if (object == null) {
-      return SystemMetaObject.NULL_META_OBJECT;
+      return NULL_META_OBJECT;
     } else {
       return new MetaObject(object, objectFactory, objectWrapperFactory, reflectorFactory);
     }
@@ -113,7 +116,7 @@ public Object getValue(String name) {
     PropertyTokenizer prop = new PropertyTokenizer(name);
     if (prop.hasNext()) {
       MetaObject metaValue = metaObjectForProperty(prop.getIndexedName());
-      if (metaValue == SystemMetaObject.NULL_META_OBJECT) {
+      if (metaValue == NULL_META_OBJECT) {
         return null;
       } else {
         return metaValue.getValue(prop.getChildren());
@@ -127,7 +130,7 @@ public void setValue(String name, Object value) {
     PropertyTokenizer prop = new PropertyTokenizer(name);
     if (prop.hasNext()) {
       MetaObject metaValue = metaObjectForProperty(prop.getIndexedName());
-      if (metaValue == SystemMetaObject.NULL_META_OBJECT) {
+      if (metaValue == NULL_META_OBJECT) {
         if (value == null) {
           // don't instantiate child path if value is null
           return;

src/main/java/org/apache/ibatis/reflection/SystemMetaObject.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,29 +15,17 @@
  */
 package org.apache.ibatis.reflection;
 
-import org.apache.ibatis.reflection.factory.DefaultObjectFactory;
-import org.apache.ibatis.reflection.factory.ObjectFactory;
-import org.apache.ibatis.reflection.wrapper.DefaultObjectWrapperFactory;
-import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
-
 /**
  * @author Clinton Begin
  */
 public final class SystemMetaObject {
 
-  public static final ObjectFactory DEFAULT_OBJECT_FACTORY = new DefaultObjectFactory();
-  public static final ObjectWrapperFactory DEFAULT_OBJECT_WRAPPER_FACTORY = new DefaultObjectWrapperFactory();
-  public static final MetaObject NULL_META_OBJECT = MetaObject.forObject(new NullObject(), DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());
-
   private SystemMetaObject() {
     // Prevent Instantiation of Static Class
   }
 
-  private static class NullObject {
-  }
-
   public static MetaObject forObject(Object object) {
-    return MetaObject.forObject(object, DEFAULT_OBJECT_FACTORY, DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());
+    return MetaObject.forObject(object, MetaObject.DEFAULT_OBJECT_FACTORY, MetaObject.DEFAULT_OBJECT_WRAPPER_FACTORY, new DefaultReflectorFactory());
   }
 
 }

src/main/java/org/apache/ibatis/reflection/wrapper/BaseWrapper.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2009-2021 the original author or authors.
+ *    Copyright 2009-2022 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -15,13 +15,13 @@
  */
 package org.apache.ibatis.reflection.wrapper;
 
-import java.util.List;
-import java.util.Map;
-
 import org.apache.ibatis.reflection.MetaObject;
 import org.apache.ibatis.reflection.ReflectionException;
 import org.apache.ibatis.reflection.property.PropertyTokenizer;
 
+import java.util.List;
+import java.util.Map;
+
 /**
  * @author Clinton Begin
  */
@@ -104,4 +104,18 @@ protected void setCollectionValue(PropertyTokenizer prop, Object collection, Obj
     }
   }
 
+  @Override
+  public boolean isCollection() {
+    return false;
+  }
+
+  @Override
+  public void add(Object element) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public <E> void addAll(List<E> list) {
+    throw new UnsupportedOperationException();
+  }
 }