pkcache.java

利用java反射机制

// FIXME CONCURRENT ACCESS TO DRIVER, URL ETC...??
package org.julp;

import java.util.*;

    /** 
     * Retrieves and caches PrimaryKeys form DatabaseMetaData          
     */

public class PKCache implements java.io.Serializable, Cloneable {
      
    private PKCache() {
        if (Boolean.getBoolean("debug-julp") || Boolean.getBoolean("debug-" + getClass().getName())){
            debug = true;
        }        
    }
    
    private static PKCache instance = null;
    /*PK for each table */
    protected Map pkCache = new HashMap();    
    protected DBServices dbServices = null;
    protected String dataSourceName = null;
    protected String dbUrl = null;
    private String userName = null;
    private String password = null;
    private String driverName = null;
    private Properties optionalConnectionProp = null;
    protected boolean useDataSource = true;
    protected boolean debug = false;
    
    public static PKCache getInstance() {
        // Not completely thread-safe, but good enough?
        if (instance == null) {
            instance = new PKCache();
        }
        return instance;
    }
    
    /*
     *This method allows to set columns for a table PrimaryKey without Database connection, etc.
     *
     * Make sure to use format:  catalog + "." + schema + "." + table + "." + column
     *   or schema + "." + table + "." + column     
     */
    public synchronized void setPrimaryKey(String catalog, String schema, String table, List pk){
        String tableId = null;
        if (catalog != null && !catalog.trim().equals("")){
            tableId = catalog + "." + schema + "." + table;
        }else if (schema != null && !schema.trim().equals("")){
            tableId = schema + "." + table;
        }else if (table != null && !table.trim().equals("")){
            tableId = table;
        }else{
            throw new IllegalArgumentException("setPrimaryKey(): missing all table identifiers");
        }
        if (pk == null || pk.size() == 0){
            throw new IllegalArgumentException("setPrimaryKey(): PK list is empty");
        }
        if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::setPrimaryKey()::tableId: " + tableId + " pk: " + pk);       
        pkCache.put(tableId, pk);
    }
    
    public synchronized List getPrimaryKey(String catalog, String schema, String table){
        String tableId = null;
        if (catalog != null && !catalog.trim().equals("")){
            tableId = catalog + "." + schema + "." + table;
        }else if (schema != null && !schema.trim().equals("")){
            tableId = schema + "." + table;
        }else if (table != null && !table.trim().equals("")){
            tableId = table;
        }else{
            throw new IllegalArgumentException("setPrimaryKey(): missing all table identifiers");
        }        
        List pkFields = (List) this.pkCache.get(tableId);
        if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::tableId: " + tableId + " pkFields: " + pkFields);
        if (pkFields != null) {
            return pkFields; //it's already cached
        }else{
            pkFields = new ArrayList();
        }
        java.sql.ResultSet pkInfo = null;
        try{
            if (dbServices == null){
                dbServices = new DBServices();
            }
            
            if (this.isUseDataSource()){
                if (dbServices.getDataSourceName() == null || !dbServices.getDataSourceName().equals(this.dataSourceName)){
                    dbServices.release(true);
                    dbServices.setDataSourceName(this.dataSourceName);
                }
            }else{
                dbServices.setUseDataSource(false);
                if (dbServices.getDriverName() == null || !dbServices.getDriverName().equals(this.driverName) ||
                    dbServices.getDbUrl() == null || !dbServices.getDbUrl().equals(this.dbUrl) ||
                    dbServices.getUserName() == null || !dbServices.getUserName().equals(this.userName) ||
                    dbServices.getPassword() == null || !dbServices.getPassword().equals(this.password)){
                    dbServices.release(true);
                    dbServices.setConnectionProperties(this.optionalConnectionProp);
                    dbServices.setDriverName(this.driverName);
                    dbServices.setDbUrl(this.dbUrl);
                    dbServices.setUserName(this.userName);
                    dbServices.setPassword(this.password);
                }
            }
            java.sql.DatabaseMetaData dbmd = dbServices.getConnection().getMetaData();
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::DatabaseMetaData: " + dbmd);
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::catalog: " + catalog);
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::schema: " + schema);
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::table: " + table);
            pkInfo = dbmd.getPrimaryKeys(catalog, schema, table);
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::pkInfo: " + pkInfo);
            while(pkInfo.next()){
                if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::pkInfo.next()");
                String columnName = pkInfo.getString(4);
                pkFields.add(tableId + "." + columnName);
            }
            if (debug) System.out.println("julp ============= " + new java.util.Date() + " " + this.getClass() + "::getPrimaryKey()::pkFields: " + pkFields);
            if (pkFields.isEmpty()){
                throw new java.sql.SQLException("Cannot retrieve PrimaryKey info from DatabaseMetaData");
            }
        }catch (java.sql.SQLException sqle){
            throw new RuntimeException(sqle);
        }catch (Exception e){
            throw new RuntimeException(e);
        }finally{
            try{
                if (pkInfo != null) pkInfo.close();
                dbServices.release(true);
            }catch (java.sql.SQLException sqle){
                sqle.printStackTrace();
                throw new RuntimeException(sqle);
            }
        }
        pkCache.put(tableId, pkFields);
        return pkFields;
    }
    
//    public void setMetaData(String objectClassName, MetaData metaData){
//        metaDataMap.put(objectClassName, metaData);
//    }
//    
//    public MetaData getMetaData(String objectClassName){
//        return (MetaData) metaDataMap.get(objectClassName);
//    }
    
    /** Getter for property dbServices.
     * @return Value of property dbServices.
     *
     */
    public org.julp.DBServices getDbServices() {
        return dbServices;
    }
    
    /** Setter for property dbServices.
     * @param dbServices New value of property dbServices.
     *
     */
    public void setDbServices(org.julp.DBServices dbServices) {
        this.dbServices = dbServices;
    }
    
    /** Getter for property dataSourceName.
     * @return Value of property dataSourceName.
     *
     */
    public java.lang.String getDataSourceName() {
        return dataSourceName;
    }
    
    /** Setter for property dataSourceName.
     * @param dataSourceName New value of property dataSourceName.
     *
     */
    public void setDataSourceName(java.lang.String dataSourceName) {
        this.dataSourceName = dataSourceName;
    }
    
    /** Getter for property dbUrl.
     * @return Value of property dbUrl.
     *
     */
    public java.lang.String getDbUrl() {
        return dbUrl;
    }
    
    /** Setter for property dbUrl.
     * @param dbUrl New value of property dbUrl.
     *
     */
    public void setDbUrl(java.lang.String dbUrl) {
        this.dbUrl = dbUrl;
    }
    
    /** Getter for property userName.
     * @return Value of property userName.
     *
     */
    public java.lang.String getUserName() {
        return userName;
    }
    
    /** Setter for property userName.
     * @param userName New value of property userName.
     *
     */
    public void setUserName(java.lang.String userName) {
        this.userName = userName;
    }
    
    /** Getter for property password.
     * @return Value of property password.
     *
     */
    public java.lang.String getPassword() {
        return password;
    }
    
    /** Setter for property password.
     * @param password New value of property password.
     *
     */
    public void setPassword(java.lang.String password) {
        this.password = password;
    }
    
    /** Getter for property useDataSource.
     * @return Value of property useDataSource.
     *
     */
    public boolean isUseDataSource() {
        return useDataSource;
    }
    
    /** Setter for property useDataSource.
     * @param useDataSource New value of property useDataSource.
     *
     */
    public void setUseDataSource(boolean useDataSource) {
        this.useDataSource = useDataSource;
    }
    
    /** Getter for property driverName.
     * @return Value of property driverName.
     *
     */
    public java.lang.String getDriverName() {
        return driverName;
    }
    
    /** Setter for property driverName.
     * @param driverName New value of property driverName.
     *
     */
    public void setDriverName(java.lang.String driverName) {
        this.driverName = driverName;
    }    
    
    /** Getter for property optionalConnectionProp.
     * @return Value of property optionalConnectionProp.
     *
     */
    public java.util.Properties getOptionalConnectionProp() {
        return optionalConnectionProp;
    }
    
    /** Setter for property optionalConnectionProp.
     * @param optionalConnectionProp New value of property optionalConnectionProp.
     *
     */
    public void setOptionalConnectionProp(java.util.Properties optionalConnectionProp) {
        this.optionalConnectionProp = optionalConnectionProp;
    }
    
}