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MySQL JDBC Type 4 driver
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/*
 Copyright (c) 2005, 2012, Oracle and/or its affiliates. All rights reserved.
 

  The MySQL Connector/J is licensed under the terms of the GPLv2
  , like most MySQL Connectors.
  There are special exceptions to the terms and conditions of the GPLv2 as it is applied to
  this software, see the FLOSS License Exception
  .

  This program is free software; you can redistribute it and/or modify it under the terms
  of the GNU General Public License as published by the Free Software Foundation; version 2
  of the License.

  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with this
  program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
  Floor, Boston, MA 02110-1301  USA

 */

package com.mysql.jdbc;

import java.sql.ParameterMetaData;
import java.sql.SQLException;
import java.sql.Types;

public class MysqlParameterMetadata implements ParameterMetaData {
	boolean returnSimpleMetadata = false;

	ResultSetMetaData metadata = null;

	int parameterCount = 0;

	private ExceptionInterceptor exceptionInterceptor;
	
	MysqlParameterMetadata(Field[] fieldInfo, int parameterCount, ExceptionInterceptor exceptionInterceptor) {
		this.metadata = new ResultSetMetaData(fieldInfo, false, exceptionInterceptor);

		this.parameterCount = parameterCount;
		this.exceptionInterceptor = exceptionInterceptor;
	}

	/**
	 * Used for "fake" basic metadata for client-side prepared statements when
	 * we don't know the parameter types.
	 * 
	 * @param parameterCount
	 */
	MysqlParameterMetadata(int count) {
		this.parameterCount = count;
		this.returnSimpleMetadata = true;
	}

	public int getParameterCount() throws SQLException {
		return this.parameterCount;
	}

	public int isNullable(int arg0) throws SQLException {
		checkAvailable();

		return this.metadata.isNullable(arg0);
	}

	private void checkAvailable() throws SQLException {
		if (this.metadata == null || this.metadata.fields == null) {
			throw SQLError.createSQLException(
					"Parameter metadata not available for the given statement",
					SQLError.SQL_STATE_DRIVER_NOT_CAPABLE, this.exceptionInterceptor);
		}
	}

	public boolean isSigned(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return false;
		}

		checkAvailable();

		return (this.metadata.isSigned(arg0));
	}

	public int getPrecision(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return 0;
		}

		checkAvailable();

		return (this.metadata.getPrecision(arg0));
	}

	public int getScale(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return 0;
		}

		checkAvailable();

		return (this.metadata.getScale(arg0));
	}

	public int getParameterType(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return Types.VARCHAR;
		}

		checkAvailable();

		return (this.metadata.getColumnType(arg0));
	}

	public String getParameterTypeName(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return "VARCHAR";
		}

		checkAvailable();

		return (this.metadata.getColumnTypeName(arg0));
	}

	public String getParameterClassName(int arg0) throws SQLException {
		if (this.returnSimpleMetadata) {
			checkBounds(arg0);

			return "java.lang.String";
		}

		checkAvailable();

		return (this.metadata.getColumnClassName(arg0));
	}

	public int getParameterMode(int arg0) throws SQLException {
		return parameterModeIn;
	}

	private void checkBounds(int paramNumber) throws SQLException {
		if (paramNumber < 1) {
			throw SQLError.createSQLException("Parameter index of '"
					+ paramNumber + "' is invalid.",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
		}

		if (paramNumber > this.parameterCount) {
			throw SQLError.createSQLException("Parameter index of '"
					+ paramNumber
					+ "' is greater than number of parameters, which is '"
					+ this.parameterCount + "'.",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);

		}
	}
	
	/**
     * Returns true if this either implements the interface argument or is directly or indirectly a wrapper
     * for an object that does. Returns false otherwise. If this implements the interface then return true,
     * else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped
     * object. If this does not implement the interface and is not a wrapper, return false.
     * This method should be implemented as a low-cost operation compared to unwrap so that
     * callers can use this method to avoid expensive unwrap calls that may fail. If this method
     * returns true then calling unwrap with the same argument should succeed.
     *
     * @param interfaces a Class defining an interface.
     * @return true if this implements the interface or directly or indirectly wraps an object that does.
     * @throws java.sql.SQLException  if an error occurs while determining whether this is a wrapper
     * for an object with the given interface.
     * @since 1.6
     */
	public boolean isWrapperFor(Class iface) throws SQLException {

		// This works for classes that aren't actually wrapping
		// anything
		return iface.isInstance(this);
	}

    /**
     * Returns an object that implements the given interface to allow access to non-standard methods,
     * or standard methods not exposed by the proxy.
     * The result may be either the object found to implement the interface or a proxy for that object.
     * If the receiver implements the interface then that is the object. If the receiver is a wrapper
     * and the wrapped object implements the interface then that is the object. Otherwise the object is
     *  the result of calling unwrap recursively on the wrapped object. If the receiver is not a
     * wrapper and does not implement the interface, then an SQLException is thrown.
     *
     * @param iface A Class defining an interface that the result must implement.
     * @return an object that implements the interface. May be a proxy for the actual implementing object.
     * @throws java.sql.SQLException If no object found that implements the interface 
     * @since 1.6
     */
	public Object unwrap(Class iface) throws java.sql.SQLException {
    	try {
    		// This works for classes that aren't actually wrapping
    		// anything
    		return Util.cast(iface, this);
        } catch (ClassCastException cce) {
            throw SQLError.createSQLException("Unable to unwrap to " + iface.toString(), 
            		SQLError.SQL_STATE_ILLEGAL_ARGUMENT, this.exceptionInterceptor);
        }
    }
}