Add implementation for methods "isWrapperFor()" and "unwrap()" in JdbcDatabaseMetaData,

JdbcParameterMetaData,JdbcResultSet,JdbcResultSetMetaData,JdbcStatement

h2/src/main/org/h2/jdbc/JdbcDatabaseMetaData.java

@@ -13,6 +13,7 @@ import java.sql.RowIdLifetime;
 import java.sql.SQLException;
 import org.h2.engine.Constants;
 import org.h2.engine.SysProperties;
+import org.h2.message.DbException;
 import org.h2.message.Trace;
 import org.h2.message.TraceObject;
 import org.h2.tools.SimpleResultSet;
@@ -3072,19 +3073,29 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     }
 
     /**
-     * [Not supported] Return an object of this class if possible.
+     * Return an object of this class if possible.
+     *
+     * @param iface the class
+     * @return this
      */
     @Override
+    @SuppressWarnings("unchecked")
     public <T> T unwrap(Class<T> iface) throws SQLException {
-        throw unsupported("unwrap");
+        if (isWrapperFor(iface)) {
+            return (T) this;
+        }
+        throw DbException.getInvalidValueException("iface", iface);
     }
 
     /**
-     * [Not supported] Checks if unwrap can return an object of this class.
+     * Checks if unwrap can return an object of this class.
+     *
+     * @param iface the class
+     * @return whether or not the interface is assignable from this class
      */
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        throw unsupported("isWrapperFor");
+        return iface != null && iface.isAssignableFrom(getClass());
     }
 
     /**

h2/src/main/org/h2/jdbc/JdbcParameterMetaData.java

@@ -219,19 +219,29 @@ public class JdbcParameterMetaData extends TraceObject implements
     }
 
     /**
-     * [Not supported] Return an object of this class if possible.
+     * Return an object of this class if possible.
+     *
+     * @param iface the class
+     * @return this
      */
     @Override
+    @SuppressWarnings("unchecked")
     public <T> T unwrap(Class<T> iface) throws SQLException {
-        throw unsupported("unwrap");
+        if (isWrapperFor(iface)) {
+            return (T) this;
+        }
+        throw DbException.getInvalidValueException("iface", iface);
     }
 
     /**
-     * [Not supported] Checks if unwrap can return an object of this class.
+     * Checks if unwrap can return an object of this class.
+     *
+     * @param iface the class
+     * @return whether or not the interface is assignable from this class
      */
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        throw unsupported("isWrapperFor");
+        return iface != null && iface.isAssignableFrom(getClass());
     }
 
     /**

h2/src/main/org/h2/jdbc/JdbcResultSet.java

@@ -27,7 +27,6 @@ import java.sql.Timestamp;
 import java.util.Calendar;
 import java.util.HashMap;
 import java.util.Map;
-
 import org.h2.api.ErrorCode;
 import org.h2.engine.SysProperties;
 import org.h2.message.DbException;
@@ -3646,19 +3645,29 @@ public class JdbcResultSet extends TraceObject implements ResultSet {
     }
 
     /**
-     * [Not supported] Return an object of this class if possible.
+     * Return an object of this class if possible.
+     *
+     * @param iface the class
+     * @return this
      */
     @Override
+    @SuppressWarnings("unchecked")
     public <T> T unwrap(Class<T> iface) throws SQLException {
-        throw unsupported("unwrap");
+        if (isWrapperFor(iface)) {
+            return (T) this;
+        }
+        throw DbException.getInvalidValueException("iface", iface);
     }
 
     /**
-     * [Not supported] Checks if unwrap can return an object of this class.
+     * Checks if unwrap can return an object of this class.
+     *
+     * @param iface the class
+     * @return whether or not the interface is assignable from this class
      */
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        throw unsupported("isWrapperFor");
+        return iface != null && iface.isAssignableFrom(getClass());
     }
 
     /**

h2/src/main/org/h2/jdbc/JdbcResultSetMetaData.java

@@ -7,7 +7,6 @@ package org.h2.jdbc;
 
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
-
 import org.h2.message.DbException;
 import org.h2.message.Trace;
 import org.h2.message.TraceObject;
@@ -450,19 +449,29 @@ public class JdbcResultSetMetaData extends TraceObject implements
     }
 
     /**
-     * [Not supported] Return an object of this class if possible.
+     * Return an object of this class if possible.
+     *
+     * @param iface the class
+     * @return this
      */
     @Override
+    @SuppressWarnings("unchecked")
     public <T> T unwrap(Class<T> iface) throws SQLException {
-        throw unsupported("unwrap");
+        if (isWrapperFor(iface)) {
+            return (T) this;
+        }
+        throw DbException.getInvalidValueException("iface", iface);
     }
 
     /**
-     * [Not supported] Checks if unwrap can return an object of this class.
+     * Checks if unwrap can return an object of this class.
+     *
+     * @param iface the class
+     * @return whether or not the interface is assignable from this class
      */
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        throw unsupported("isWrapperFor");
+        return iface != null && iface.isAssignableFrom(getClass());
     }
 
     /**

h2/src/main/org/h2/jdbc/JdbcStatement.java

@@ -11,7 +11,6 @@ import java.sql.SQLException;
 import java.sql.SQLWarning;
 import java.sql.Statement;
 import java.util.ArrayList;
-
 import org.h2.api.ErrorCode;
 import org.h2.command.CommandInterface;
 import org.h2.engine.SessionInterface;
@@ -1060,19 +1059,29 @@ public class JdbcStatement extends TraceObject implements Statement {
     }
 
     /**
-     * [Not supported] Return an object of this class if possible.
+     * Return an object of this class if possible.
+     *
+     * @param iface the class
+     * @return this
      */
     @Override
+    @SuppressWarnings("unchecked")
     public <T> T unwrap(Class<T> iface) throws SQLException {
-        throw unsupported("unwrap");
+        if (isWrapperFor(iface)) {
+            return (T) this;
+        }
+        throw DbException.getInvalidValueException("iface", iface);
     }
 
     /**
-     * [Not supported] Checks if unwrap can return an object of this class.
+     * Checks if unwrap can return an object of this class.
+     *
+     * @param iface the class
+     * @return whether or not the interface is assignable from this class
      */
     @Override
     public boolean isWrapperFor(Class<?> iface) throws SQLException {
-        throw unsupported("isWrapperFor");
+        return iface != null && iface.isAssignableFrom(getClass());
     }
 
     /**