Fix inconsistency between `isWrapperFor` and `unwrap` (#2243)

Closes GH-2237

src/main/java/com/zaxxer/hikari/pool/ProxyCallableStatement.java

@@ -19,7 +19,7 @@ package com.zaxxer.hikari.pool;
 import java.sql.CallableStatement;
 
 /**
- * This is the proxy class for java.sql.CallableStatement.
+ * This is the proxy class for {@link CallableStatement}.
  *
  * @author Brett Wooldridge
  */

src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java

@@ -30,7 +30,7 @@ import java.util.concurrent.Executor;
 import static com.zaxxer.hikari.SQLExceptionOverride.Override.DO_NOT_EVICT;
 
 /**
- * This is the proxy class for java.sql.Connection.
+ * This is the proxy class for {@link Connection}.
  *
  * @author Brett Wooldridge
  */

src/main/java/com/zaxxer/hikari/pool/ProxyDatabaseMetaData.java

@@ -5,6 +5,12 @@ import java.sql.DatabaseMetaData;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 
+/**
+ * This is the proxy class for {@link DatabaseMetaData}.
+ *
+ * @author Brett Wooldridge
+ * @author Yanming Zhou
+ */
 public abstract class ProxyDatabaseMetaData implements DatabaseMetaData
 {
    protected final ProxyConnection connection;
@@ -302,6 +308,13 @@ public abstract class ProxyDatabaseMetaData implements DatabaseMetaData
       return ProxyFactory.getProxyResultSet(connection, (ProxyStatement) statement, resultSet);
    }
 
+   /** {@inheritDoc} */
+   @Override
+   public final boolean isWrapperFor(Class<?> iface) throws SQLException
+   {
+      return iface.isInstance(delegate) || (delegate != null && delegate.isWrapperFor(iface));
+   }
+
    /** {@inheritDoc} */
    @Override
    @SuppressWarnings("unchecked")

src/main/java/com/zaxxer/hikari/pool/ProxyPreparedStatement.java

@@ -21,7 +21,7 @@ import java.sql.ResultSet;
 import java.sql.SQLException;
 
 /**
- * This is the proxy class for java.sql.PreparedStatement.
+ * This is the proxy class for {@link PreparedStatement}.
  *
  * @author Brett Wooldridge
  */

src/main/java/com/zaxxer/hikari/pool/ProxyResultSet.java

@@ -21,9 +21,10 @@ import java.sql.SQLException;
 import java.sql.Statement;
 
 /**
- * This is the proxy class for java.sql.ResultSet.
+ * This is the proxy class for {@link ResultSet}.
  *
  * @author Brett Wooldridge
+ * @author Yanming Zhou
  */
 public abstract class ProxyResultSet implements ResultSet
 {
@@ -85,6 +86,13 @@ public abstract class ProxyResultSet implements ResultSet
       delegate.deleteRow();
    }
 
+   /** {@inheritDoc} */
+   @Override
+   public final boolean isWrapperFor(Class<?> iface) throws SQLException
+   {
+      return iface.isInstance(delegate) || (delegate != null && delegate.isWrapperFor(iface));
+   }
+
    /** {@inheritDoc} */
    @Override
    @SuppressWarnings("unchecked")

src/main/java/com/zaxxer/hikari/pool/ProxyStatement.java

@@ -22,9 +22,10 @@ import java.sql.SQLException;
 import java.sql.Statement;
 
 /**
- * This is the proxy class for java.sql.Statement.
+ * This is the proxy class for {@link Statement}.
  *
  * @author Brett Wooldridge
+ * @author Yanming Zhou
  */
 public abstract class ProxyStatement implements Statement
 {
@@ -233,6 +234,13 @@ public abstract class ProxyStatement implements Statement
       return proxyResultSet;
    }
 
+   /** {@inheritDoc} */
+   @Override
+   public final boolean isWrapperFor(Class<?> iface) throws SQLException
+   {
+      return iface.isInstance(delegate) || (delegate != null && delegate.isWrapperFor(iface));
+   }
+
    /** {@inheritDoc} */
    @Override
    @SuppressWarnings("unchecked")