environment.java

JSP+SQL编写的人力资源管理系统

	/**
	 * Validate connection when returning connection to pool (optional, true or false)
	 */
	public static final String DBCP_VALIDATION_ONRETURN = "hibernate.dbcp.testOnReturn";
	/**
	 * Query to execute for connection validation (optional, requires either 
	 * <tt>DBCP_VALIDATION_ONBORROW</tt> or <tt>DBCP_VALIDATION_ONRETURN</tt>)
	 */
	public static final String DBCP_VALIDATION_QUERY = "hibernate.dbcp.validationQuery";
	/**
	 * Maximum number of checked out statements for DBCP
	 */
	public static final String DBCP_PS_MAXACTIVE = "hibernate.dbcp.ps.maxActive";
	/**
	 * Maximum number of idle statements for DBCP
	 */
	public static final String DBCP_PS_MAXIDLE = "hibernate.dbcp.ps.maxIdle";
	/**
	 * Maximum idle time for statements in DBCP (ms)
	 */
	public static final String DBCP_PS_MAXWAIT = "hibernate.dbcp.ps.maxWait";
	/**
	 * Action to take in case of an exhausted DBCP statement pool ( 0 = fail, 1 = block, 2= grow)
	 */
	public static final String DBCP_PS_WHENEXHAUSTED = "hibernate.dbcp.ps.whenExhaustedAction";
	
	/**
	 * Proxool/Hibernate property prefix
	 */
	public static final String PROXOOL_PREFIX = "hibernate.proxool";
	/**
	 * Proxool property to configure the Proxool Provider using an XML (<tt>/path/to/file.xml</tt>)
	 */  
	public static final String PROXOOL_XML = "hibernate.proxool.xml";
	/**
	 * Proxool property to configure the Proxool Provider  using a properties file (<tt>/path/to/proxool.properties</tt>)
	 */    
	public static final String PROXOOL_PROPERTIES = "hibernate.proxool.properties";
	/**
	 * Proxool property to configure the Proxool Provider from an already existing pool (<tt>true</tt> / <tt>false</tt>)
	 */    
	public static final String PROXOOL_EXISTING_POOL = "hibernate.proxool.existing_pool";
	/**
	 * Proxool property with the Proxool pool alias to use
	 * (Required for <tt>PROXOOL_EXISTING_POOL</tt>, <tt>PROXOOL_PROPERTIES</tt>, or 
	 * <tt>PROXOOL_XML</tt>)
	 */  
	public static final String PROXOOL_POOL_ALIAS = "hibernate.proxool.pool_alias";  	

	/**
	 * <tt>TransactionFactory</tt> implementor to use for creating <tt>Transaction</tt>s
	 */
	public static final String TRANSACTION_STRATEGY = "hibernate.transaction.factory_class";
	/**
	 * <tt>TransactionManagerLookup</tt> implementor to use for obtaining the <tt>TransactionManager</tt>
	 */
	public static final String TRANSACTION_MANAGER_STRATEGY = "hibernate.transaction.manager_lookup_class";
	/**
	 * JNDI name of JTA <tt>UserTransaction</tt> object
	 */
	public static final String USER_TRANSACTION = "jta.UserTransaction";
	
	/**
	 * The <tt>CacheProvider</tt> implementation class
	 */
	public static final String CACHE_PROVIDER = "hibernate.cache.provider_class";
	/**
	 * The <tt>CacheProvider</tt> implementation class
	 */
	public static final String USE_QUERY_CACHE = "hibernate.cache.use_query_cache";
	/**
	 * The <tt>CacheProvider</tt> region name prefix
	 */
	public static final String CACHE_REGION_PREFIX = "hibernate.cache.region_prefix";
	/**
	 * Optimize the cache for mimimal puts instead of minimal gets
	 */
	public static final String USE_MINIMAL_PUTS = "hibernate.cache.use_minimal_puts";

	/**
	 * Use CGLIB <tt>MetaClass</tt> to optimize property access
	 */
	public static final String USE_REFLECTION_OPTIMIZER = "hibernate.cglib.use_reflection_optimizer";
	
	/**
	 * A comma-seperated list of token substitutions to use when translating a Hibernate
	 * query to SQL
	 */
	public static final String QUERY_SUBSTITUTIONS = "hibernate.query.substitutions";
	/**
	 * A comma-seperated list of packages that need not be specified in a query
	 * @deprecated
	 */
	public static final String QUERY_IMPORTS = "hibernate.query.imports";
	/**
	 * Auto export/update schema using hbm2ddl tool. Valid values are <tt>update</tt>, <tt>create</tt>
	 * and <tt>create-drop</tt>.
	 */
	public static final String HBM2DDL_AUTO = "hibernate.hbm2ddl.auto";
	
	//Obsolete properties:
	
	private static final String OUTPUT_STYLESHEET_OLD ="hibernate.output_stylesheet";
	private static final String CONNECTION_PROVIDER_OLD ="hibernate.connection_provider";
	private static final String DRIVER_OLD ="hibernate.driver";
	private static final String ISOLATION_OLD ="hibernate.isolation";
	private static final String USER_OLD ="hibernate.username";
	private static final String PASS_OLD ="hibernate.password";
	private static final String POOL_SIZE_OLD ="hibernate.pool_size";
	private static final String STATEMENT_CACHE_SIZE_OLD ="hibernate.statement_cache_size";
	private static final String DATASOURCE_OLD ="hibernate.datasource";
	private static final String TRANSACTION_STRATEGY_OLD = "hibernate.transaction_factory";
	private static final String URL_OLD ="hibernate.url";
	private static final String USE_STREAMS_FOR_BINARY_OLD = "hibernate.use_streams_for_binary";
	private static final String STATEMENT_FETCH_SIZE_OLD = "hibernate.statement.fetch_size";
	private static final String USE_SCROLLABLE_RESULTSET_OLD = "hibernate.use_scrollable_resultset";
	/**
	 * Use JDBC2 batch updates
	 * @deprecated
	 */
	public static final String USE_JDBC_BATCH = "hibernate.use_jdbc_batch";
	
	private static final boolean ENABLE_BINARY_STREAMS;
	private static final boolean ENABLE_REFLECTION_OPTIMIZER;
	private static final boolean JVM_SUPPORTS_LINKED_HASH_COLLECTIONS;
	private static final boolean JVM_HAS_TIMESTAMP_BUG;
	private static final boolean JVM_SUPPORTS_GET_GENERATED_KEYS;
	
	private static final Properties GLOBAL_PROPERTIES;
	private static final HashMap ISOLATION_LEVELS = new HashMap();
	private static final Map OBSOLETE_PROPERTIES = new HashMap();
	
	private static final Log log = LogFactory.getLog(Environment.class);
	
	/**
	 * Issues warnings to the user when any obsolete property names are used.
	 */
	public static void verifyProperties(Properties props) {
		Iterator iter = props.keySet().iterator();
		while ( iter.hasNext() ) {
			Object oldProp = iter.next();
			Object newProp = OBSOLETE_PROPERTIES.get(oldProp);
			if ( newProp!=null ) log.warn("Usage of obsolete property: " + oldProp + " no longer supported, use: " + newProp);
		}
	}
	
	static {
		
		log.info("Hibernate " + VERSION);
		
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_NONE), "NONE" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_READ_UNCOMMITTED), "READ_UNCOMMITTED" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_READ_COMMITTED), "READ_COMMITTED" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_REPEATABLE_READ), "REPEATABLE_READ" );
		ISOLATION_LEVELS.put( new Integer(Connection.TRANSACTION_SERIALIZABLE), "SERIALIZABLE" );
		
		OBSOLETE_PROPERTIES.put(CONNECTION_PROVIDER_OLD, CONNECTION_PROVIDER);
		OBSOLETE_PROPERTIES.put(DRIVER_OLD, DRIVER);
		OBSOLETE_PROPERTIES.put(ISOLATION_OLD, ISOLATION);
		OBSOLETE_PROPERTIES.put(URL_OLD, URL);
		OBSOLETE_PROPERTIES.put(PASS_OLD, PASS);
		OBSOLETE_PROPERTIES.put(USER_OLD, USER);
		OBSOLETE_PROPERTIES.put(POOL_SIZE_OLD, POOL_SIZE);
		OBSOLETE_PROPERTIES.put(STATEMENT_CACHE_SIZE_OLD, STATEMENT_CACHE_SIZE);
		OBSOLETE_PROPERTIES.put(DATASOURCE_OLD, DATASOURCE);
		OBSOLETE_PROPERTIES.put(TRANSACTION_STRATEGY_OLD, TRANSACTION_STRATEGY);
		OBSOLETE_PROPERTIES.put(OUTPUT_STYLESHEET_OLD, OUTPUT_STYLESHEET);
		OBSOLETE_PROPERTIES.put(USE_JDBC_BATCH, STATEMENT_BATCH_SIZE);
		OBSOLETE_PROPERTIES.put(USE_SCROLLABLE_RESULTSET_OLD, USE_SCROLLABLE_RESULTSET);
		OBSOLETE_PROPERTIES.put(USE_STREAMS_FOR_BINARY_OLD, USE_STREAMS_FOR_BINARY);
		OBSOLETE_PROPERTIES.put(STATEMENT_FETCH_SIZE_OLD, STATEMENT_FETCH_SIZE);
		
		GLOBAL_PROPERTIES = new Properties();
		GLOBAL_PROPERTIES.setProperty( USE_REFLECTION_OPTIMIZER, Boolean.TRUE.toString() );
		
		InputStream stream = Environment.class.getResourceAsStream("/hibernate.properties");
		if ( stream==null ) {
			log.info("hibernate.properties not found");
		}
		else {
			try {
				GLOBAL_PROPERTIES.load(stream);
				log.info("loaded properties from resource hibernate.properties: " + GLOBAL_PROPERTIES);
			}
			catch (Exception e) {
				log.error("problem loading properties from hibernate.properties");
			} 
			finally {
				try{
					stream.close();
				} 
				catch (IOException ioe){
					log.error("could not close stream on hibernate.properties", ioe);	
				}
			}
		}
		
		GLOBAL_PROPERTIES.putAll( System.getProperties() );
		
		verifyProperties(GLOBAL_PROPERTIES);
		
		ENABLE_BINARY_STREAMS = PropertiesHelper.getBoolean(USE_STREAMS_FOR_BINARY, GLOBAL_PROPERTIES);
		ENABLE_REFLECTION_OPTIMIZER = PropertiesHelper.getBoolean(USE_REFLECTION_OPTIMIZER, GLOBAL_PROPERTIES);
		
		if (ENABLE_BINARY_STREAMS) log.info("using java.io streams to persist binary types");
		if (ENABLE_REFLECTION_OPTIMIZER) log.info("using CGLIB reflection optimizer");

		boolean getGeneratedKeysSupport;
		try {
			Statement.class.getDeclaredMethod("getGeneratedKeys", null);
			getGeneratedKeysSupport = true;
		}
		catch (NoSuchMethodException nsme) {
			getGeneratedKeysSupport = false;
		}		
		JVM_SUPPORTS_GET_GENERATED_KEYS = getGeneratedKeysSupport;
		if (!JVM_SUPPORTS_GET_GENERATED_KEYS) log.info("JVM does not support Statement.getGeneratedKeys()");
		
		boolean linkedHashSupport;
		try {
			Class.forName("java.util.LinkedHashSet");
			linkedHashSupport = true;
		}
		catch (ClassNotFoundException cnfe) {
			linkedHashSupport = false;
		}
		JVM_SUPPORTS_LINKED_HASH_COLLECTIONS = linkedHashSupport;
		if (!JVM_SUPPORTS_LINKED_HASH_COLLECTIONS) log.info("JVM does not support LinkedHasMap, LinkedHashSet - ordered maps and sets disabled");
		
		JVM_HAS_TIMESTAMP_BUG = new Timestamp(123456789).getTime() != 123456789;
		if (JVM_HAS_TIMESTAMP_BUG) log.info("using workaround for JVM bug in java.sql.Timestamp");
	}
	
	/**
	 * Does this JVM support dynamic proxies. (Now return true because CGLIB
	 * proxies work on all supported JDK)
	 */
	public static boolean jvmSupportsProxies() {
		return true;//jvmSupportsProxies;
	}
	
	/**
	 * Does this JVM have the IBM JDK 1.3.1. The bug is <tt>new Timestamp(x).getTime()!=x</tt>.
	 */
	public static boolean jvmHasTimestampBug() {
		return JVM_HAS_TIMESTAMP_BUG;
	}
	
	/**
	 * Does this JVM support <tt>LinkedHashSet</tt>, <tt>LinkedHashMap</tt>.
	 * @see java.util.LinkedHashSet
	 * @see java.util.LinkedHashMap
	 */
	public static boolean jvmSupportsLinkedHashCollections() {
		return JVM_SUPPORTS_LINKED_HASH_COLLECTIONS;
	}
	
	public static boolean jvmSupportsGetGeneratedKeys() {
		return JVM_SUPPORTS_GET_GENERATED_KEYS;
	}
	
	/**
	 * Should we use streams to bind binary types to JDBC IN parameters.
	 * Property <tt>hibernate.jdbc.use_streams_for_binary</tt>.
	 * @see Environment#USE_STREAMS_FOR_BINARY
	 */
	public static boolean useStreamsForBinary() {
		return ENABLE_BINARY_STREAMS;
	}
	
	/**
	 * Should we use CGLIB reflection optimizer.
	 * Property <tt>hibernate.jdbc.use_refection_optimizer</tt>.
	 * @see Environment#USE_REFLECTION_OPTIMIZER
	 */
	public static boolean useReflectionOptimizer() {
		return ENABLE_REFLECTION_OPTIMIZER;
	}
	
	private Environment() { throw new UnsupportedOperationException(); }
	
	/**
	 * Return <tt>System</tt> properties, extended by any properties specified
	 * in <tt>hibernate.properties</tt>.
	 * @return Properties
	 */
	public static Properties getProperties() {
		Properties copy = new Properties();
		copy.putAll(GLOBAL_PROPERTIES);
		return copy;
	}
	
	/**
	 * Get the name of a JDBC transaction isolation level
	 *
	 * @see java.sql.Connection
	 * @param isolation as defined by <tt>java.sql.Connection</tt>
	 * @return a human-readable name
	 */
	public static String isolationLevelToString(int isolation) {
		return (String) ISOLATION_LEVELS.get( new Integer(isolation) );
	}
	
}