/*
 * Copyright 2002-2005 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.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.support;

import java.lang.reflect.Constructor;
import java.sql.SQLException;
import java.util.Arrays;

import javax.sql.DataSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.dao.CannotAcquireLockException;
import org.springframework.dao.CannotSerializeTransactionException;
import org.springframework.dao.DataAccessException;
import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.dao.DeadlockLoserDataAccessException;
import org.springframework.jdbc.BadSqlGrammarException;
import org.springframework.jdbc.InvalidResultSetAccessException;

/**
 * Implementation of SQLExceptionTranslator that uses specific vendor codes.
 * More precise than SQL state implementation, but vendor-specific.
 *
 * <p>This class applies the following matching rules:
 * <ul>
 * <li>Try custom translation implemented by any subclass. Note that this class is
 * concrete and is typically used itself, in which case this rule doesn't apply.
 * <li>Apply error code matching. Error codes are obtained from the SQLErrorCodesFactory
 * by default. This factory loads a "sql-error-codes.xml" file from the class path,
 * defining error code mappings for database names from database metadata.
 * <li>Fallback to fallback translator. SQLStateSQLExceptionTranslator is the default
 * fallback translator.
 * </ul>
 * 
 * @author Rod Johnson
 * @author Thomas Risberg
 * @author Juergen Hoeller
 * @see SQLErrorCodesFactory
 * @see SQLStateSQLExceptionTranslator
 */
public class SQLErrorCodeSQLExceptionTranslator implements SQLExceptionTranslator {

	private static final int MESSAGE_ONLY_CONSTRUCTOR = 1;
	private static final int MESSAGE_THROWABLE_CONSTRUCTOR = 2;
	private static final int MESSAGE_SQLEX_CONSTRUCTOR = 3;
	private static final int MESSAGE_SQL_THROWABLE_CONSTRUCTOR = 4;
	private static final int MESSAGE_SQL_SQLEX_CONSTRUCTOR = 5;


	protected final Log logger = LogFactory.getLog(getClass());

	/** Error codes used by this translator */
	private SQLErrorCodes sqlErrorCodes;
	
	/** Fallback translator to use if SQL error code matching doesn't work */
	private SQLExceptionTranslator fallbackTranslator = new SQLStateSQLExceptionTranslator();


	/**
	 * Constructor for use as a JavaBean.
	 * The SqlErrorCodes or DataSource property must be set.
	 */
	public SQLErrorCodeSQLExceptionTranslator() {
	}

	/**
	 * Create a SQL error code translator for the given DataSource.
	 * Invoking this constructor will cause a Connection to be obtained
	 * from the DataSource to get the metadata.
	 * @param dataSource DataSource to use to find metadata and establish
	 * which error codes are usable
	 * @see SQLErrorCodesFactory
	 */
	public SQLErrorCodeSQLExceptionTranslator(DataSource dataSource) {
		setDataSource(dataSource);
	}

	/**
	 * Create a SQL error code translator for the given database product name.
	 * Invoking this constructor will avoid obtaining a Connection from the
	 * DataSource to get the metadata.
	 * @param dbName the database product name that identifies the error codes entry
	 * @see SQLErrorCodesFactory
	 * @see java.sql.DatabaseMetaData#getDatabaseProductName()
	 */
	public SQLErrorCodeSQLExceptionTranslator(String dbName) {
		setDatabaseProductName(dbName);
	}

	/**
	 * Create a SQLErrorCode translator given these error codes.
	 * Does not require a database metadata lookup to be performed using a connection.
	 * @param sec error codes
	 */
	public SQLErrorCodeSQLExceptionTranslator(SQLErrorCodes sec) {
		this.sqlErrorCodes = sec;		
	}
	
	/**
	 * Set the DataSource for this translator.
	 * <p>Setting this property will cause a Connection to be obtained from
	 * the DataSource to get the metadata.
	 * @param dataSource DataSource to use to find metadata and establish
	 * which error codes are usable
	 * @see SQLErrorCodesFactory#getErrorCodes(javax.sql.DataSource)
	 * @see java.sql.DatabaseMetaData#getDatabaseProductName()
	 */
	public void setDataSource(DataSource dataSource) {
		this.sqlErrorCodes = SQLErrorCodesFactory.getInstance().getErrorCodes(dataSource);
	}

	/**
	 * Set the database product name for this translator.
	 * <p>Setting this property will avoid obtaining a Connection from the DataSource
	 * to get the metadata.
	 * @param dbName the database product name that identifies the error codes entry
	 * @see SQLErrorCodesFactory#getErrorCodes(String)
	 * @see java.sql.DatabaseMetaData#getDatabaseProductName()
	 */
	public void setDatabaseProductName(String dbName) {
		this.sqlErrorCodes = SQLErrorCodesFactory.getInstance().getErrorCodes(dbName);
	}

	/**
	 * Set custom error codes to be used for translation.
	 * @param sec custom error codes to use
	 */
	public void setSqlErrorCodes(SQLErrorCodes sec) {
		this.sqlErrorCodes = sec;
	}

	/**
	 * Return the error codes used by this translator.
	 * Usually determined via a DataSource.
	 * @see #setDataSource
	 */
	public SQLErrorCodes getSqlErrorCodes() {
		return sqlErrorCodes;
	}

	/**
	 * Override the default SQL state fallback translator.
	 * @param fallback custom fallback exception translator to use if error code
	 * translation fails
	 * @see SQLStateSQLExceptionTranslator
	 */
	public void setFallbackTranslator(SQLExceptionTranslator fallback) {
		this.fallbackTranslator = fallback;
	}

	/**
	 * Return the fallback exception translator.
	 */
	public SQLExceptionTranslator getFallbackTranslator() {
		return fallbackTranslator;
	}


	public DataAccessException translate(String task, String sql, SQLException sqlEx) {
		if (task == null) {
			task = "";
		}
		if (sql == null) {
			sql = "";
		}
		
		// First, try custom translation from overridden method.
		DataAccessException dex = customTranslate(task, sql, sqlEx);
		if (dex != null) {
			return dex;
		}

		// Check SQLErrorCodes with corresponding error code, if available.
		if (this.sqlErrorCodes != null) {
			String errorCode = null;
			if (this.sqlErrorCodes.isUseSqlStateForTranslation()) {
				errorCode = sqlEx.getSQLState();
			}
			else {
				errorCode = Integer.toString(sqlEx.getErrorCode());
			}

			if (errorCode != null) {

				// Look for defined custom translations first.
				CustomSQLErrorCodesTranslation[] customTranslations = this.sqlErrorCodes.getCustomTranslations();
				if (customTranslations != null) {
					for (int i = 0; i < customTranslations.length; i++) {
						CustomSQLErrorCodesTranslation customTranslation = customTranslations[i];
						if (Arrays.binarySearch(customTranslation.getErrorCodes(), errorCode) >= 0) {
							if (customTranslation.getExceptionClass() != null) {
								DataAccessException customException = createCustomException(
										task, sql, sqlEx, customTranslation.getExceptionClass());
								if (customException != null) {
									logTranslation(task, sql, sqlEx, true);
									return customException;
								}
							}
						}
					}
				}

				// Next, look for grouped error codes.
				if (Arrays.binarySearch(this.sqlErrorCodes.getBadSqlGrammarCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new BadSqlGrammarException(task, sql, sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getInvalidResultSetAccessCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new InvalidResultSetAccessException(task, sql, sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getDataAccessResourceFailureCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new DataAccessResourceFailureException(buildMessage(task, sql, sqlEx), sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getDataIntegrityViolationCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new DataIntegrityViolationException(buildMessage(task, sql, sqlEx), sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getCannotAcquireLockCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new CannotAcquireLockException(buildMessage(task, sql, sqlEx), sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getDeadlockLoserCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new DeadlockLoserDataAccessException(buildMessage(task, sql, sqlEx), sqlEx);
				}
				else if (Arrays.binarySearch(this.sqlErrorCodes.getCannotSerializeTransactionCodes(), errorCode) >= 0) {
					logTranslation(task, sql, sqlEx, false);
					return new CannotSerializeTransactionException(buildMessage(task, sql, sqlEx), sqlEx);
				}
			}
		}

		// We couldn't identify it more precisely - let's hand it over to the SQLState fallback translator.
		if (logger.isDebugEnabled()) {
			logger.debug("Unable to translate SQLException with errorCode '" + sqlEx.getErrorCode() +
					"', will now try the fallback translator");
		}
		return this.fallbackTranslator.translate(task, sql, sqlEx);
	}

	/**
	 * Build a message String for the given SQLException.
	 * Called when creating an instance of a generic DataAccessException class.
	 * @param task readable text describing the task being attempted
	 * @param sql SQL query or update that caused the problem. May be <code>null</code>.
	 * @param sqlEx the offending SQLException
	 * @return the message String to use
	 */
	protected String buildMessage(String task, String sql, SQLException sqlEx) {
		return task + "; SQL [" + sql + "]; " + sqlEx.getMessage();
	}

	/**
	 * Subclasses can override this method to attempt a custom mapping from SQLException
	 * to DataAccessException.
	 * @param task readable text describing the task being attempted
	 * @param sql SQL query or update that caused the problem. May be <code>null</code>.
	 * @param sqlEx the offending SQLException
	 * @return null if no custom translation was possible, otherwise a DataAccessException
	 * resulting from custom translation. This exception should include the sqlEx parameter
	 * as a nested root cause. This implementation always returns null, meaning that
	 * the translator always falls back to the default error codes.
	 */
	protected DataAccessException customTranslate(String task, String sql, SQLException sqlEx) {
		return null;
	}

	/**
	 * Create a custom DataAccessException, based on a given exception
	 * class from a CustomSQLErrorCodesTranslation definition.
	 * @param task readable text describing the task being attempted
	 * @param sql SQL query or update that caused the problem. May be <code>null</code>.
	 * @param sqlEx the offending SQLException
	 * @param exceptionClass the exception class to use, as defined in the
	 * CustomSQLErrorCodesTranslation definition
	 * @return null if the custom exception could not be created, otherwise
	 * the resulting DataAccessException. This exception should include the
	 * sqlEx parameter as a nested root cause.
	 * @see CustomSQLErrorCodesTranslation#setExceptionClass
	 */
	protected DataAccessException createCustomException(
			String task, String sql, SQLException sqlEx, Class exceptionClass) {

		// find appropriate constructor
		try {
			int constructorType = 0;
			Constructor[] constructors = exceptionClass.getConstructors();
			for (int i = 0; i < constructors.length; i++) {
				Class[] parameterTypes = constructors[i].getParameterTypes();
				if (parameterTypes.length == 1 && parameterTypes[0].equals(String.class)) {
					if (constructorType < MESSAGE_ONLY_CONSTRUCTOR)
						constructorType = MESSAGE_ONLY_CONSTRUCTOR;
				}
				if (parameterTypes.length == 2 && parameterTypes[0].equals(String.class) &&
						parameterTypes[1].equals(Throwable.class)) {
					if (constructorType < MESSAGE_THROWABLE_CONSTRUCTOR)
						constructorType = MESSAGE_THROWABLE_CONSTRUCTOR;
				}
				if (parameterTypes.length == 2 && parameterTypes[0].equals(String.class) &&
						parameterTypes[1].equals(SQLException.class)) {
					if (constructorType < MESSAGE_SQLEX_CONSTRUCTOR)
						constructorType = MESSAGE_SQLEX_CONSTRUCTOR;
				}
				if (parameterTypes.length == 3 && parameterTypes[0].equals(String.class) &&
						parameterTypes[1].equals(String.class) && parameterTypes[2].equals(Throwable.class)) {
					if (constructorType < MESSAGE_SQL_THROWABLE_CONSTRUCTOR)
						constructorType = MESSAGE_SQL_THROWABLE_CONSTRUCTOR;
				}
				if (parameterTypes.length == 3 && parameterTypes[0].equals(String.class) &&
						parameterTypes[1].equals(String.class) && parameterTypes[2].equals(SQLException.class)) {
					if (constructorType < MESSAGE_SQL_SQLEX_CONSTRUCTOR)
						constructorType = MESSAGE_SQL_SQLEX_CONSTRUCTOR;
				}
			}

			// invoke constructor
			Constructor exceptionConstructor = null;
			switch (constructorType) {
				case MESSAGE_SQL_SQLEX_CONSTRUCTOR:
					Class[] messageAndSqlAndSqlExArgsClass = new Class[] {String.class, String.class, SQLException.class};
					Object[] messageAndSqlAndSqlExArgs = new Object[] {task, sql, sqlEx};
					exceptionConstructor = exceptionClass.getConstructor(messageAndSqlAndSqlExArgsClass);
					return (DataAccessException) exceptionConstructor.newInstance(messageAndSqlAndSqlExArgs);
				case MESSAGE_SQL_THROWABLE_CONSTRUCTOR:
					Class[] messageAndSqlAndThrowableArgsClass = new Class[] {String.class, String.class, Throwable.class};
					Object[] messageAndSqlAndThrowableArgs = new Object[] {task, sql, sqlEx};
					exceptionConstructor = exceptionClass.getConstructor(messageAndSqlAndThrowableArgsClass);
					return (DataAccessException) exceptionConstructor.newInstance(messageAndSqlAndThrowableArgs);
				case MESSAGE_SQLEX_CONSTRUCTOR:
					Class[] messageAndSqlExArgsClass = new Class[] {String.class, SQLException.class};
					Object[] messageAndSqlExArgs = new Object[] {task + ": " + sqlEx.getMessage(), sqlEx};
					exceptionConstructor = exceptionClass.getConstructor(messageAndSqlExArgsClass);
					return (DataAccessException) exceptionConstructor.newInstance(messageAndSqlExArgs);
				case MESSAGE_THROWABLE_CONSTRUCTOR:
					Class[] messageAndThrowableArgsClass = new Class[] {String.class, Throwable.class};
					Object[] messageAndThrowableArgs = new Object[] {task + ": " + sqlEx.getMessage(), sqlEx};
					exceptionConstructor = exceptionClass.getConstructor(messageAndThrowableArgsClass);
					return (DataAccessException)exceptionConstructor.newInstance(messageAndThrowableArgs);
				case MESSAGE_ONLY_CONSTRUCTOR:
					Class[] messageOnlyArgsClass = new Class[] {String.class};
					Object[] messageOnlyArgs = new Object[] {task + ": " + sqlEx.getMessage()};
					exceptionConstructor = exceptionClass.getConstructor(messageOnlyArgsClass);
					return (DataAccessException) exceptionConstructor.newInstance(messageOnlyArgs);
				default:
					logger.warn("Unable to find appropriate constructor of custom exception class [" +
							exceptionClass.getName() + "]");
					return null;
				}
		}
		catch (Exception ex) {
			if (logger.isWarnEnabled()) {
				logger.warn("Unable to instantiate custom exception class [" + exceptionClass.getName() + "]", ex);
			}
			return null;
		}
	}

	private void logTranslation(String task, String sql, SQLException sqlEx, boolean custom) {
		if (logger.isDebugEnabled()) {
			String intro = custom ? "Custom translation of" : "Translating";
			logger.debug(intro + " SQLException with SQLState '" + sqlEx.getSQLState() +
					"' and errorCode '" + sqlEx.getErrorCode() + "' and message [" + sqlEx.getMessage() +
					"]; SQL was [" + sql + "] for task [" + task + "]");
		}
	}

}