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      1 /*
      2  *  Licensed to the Apache Software Foundation (ASF) under one or more
      3  *  contributor license agreements.  See the NOTICE file distributed with
      4  *  this work for additional information regarding copyright ownership.
      5  *  The ASF licenses this file to You under the Apache License, Version 2.0
      6  *  (the "License"); you may not use this file except in compliance with
      7  *  the License.  You may obtain a copy of the License at
      8  *
      9  *     http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  *  Unless required by applicable law or agreed to in writing, software
     12  *  distributed under the License is distributed on an "AS IS" BASIS,
     13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  *  See the License for the specific language governing permissions and
     15  *  limitations under the License.
     16  */
     17 
     18 /**
     19 * @author Boris V. Kuznetsov
     20 * @version $Revision$
     21 */
     22 
     23 package org.apache.harmony.security.fortress;
     24 
     25 import java.security.NoSuchAlgorithmException;
     26 import java.security.Provider;
     27 import org.apache.harmony.security.Util;
     28 
     29 
     30 /**
     31  *
     32  * This class implements common functionality for all engine classes
     33  *
     34  */
     35 public class Engine {
     36 
     37     // Service name
     38     private final String serviceName;
     39 
     40     // for getInstance(String algorithm, Object param) optimization:
     41     // previous result
     42     private Provider.Service returnedService;
     43 
     44     // previous parameter
     45     private String lastAlgorithm;
     46 
     47     private int refreshNumber;
     48 
     49     /**
     50      * Provider
     51      */
     52     public Provider provider;
     53 
     54     /**
     55      * SPI instance
     56      */
     57     public Object spi;
     58 
     59     /**
     60      * Access to package visible api in java.security
     61      */
     62     public static SecurityAccess door;
     63 
     64     /**
     65      * Creates a Engine object
     66      *
     67      * @param service
     68      */
     69     public Engine(String service) {
     70         this.serviceName = service;
     71     }
     72 
     73     /**
     74      *
     75      * Finds the appropriate service implementation and creates instance of the
     76      * class that implements corresponding Service Provider Interface.
     77      *
     78      * @param algorithm
     79      * @param service
     80      * @throws NoSuchAlgorithmException
     81      */
     82     public synchronized void getInstance(String algorithm, Object param)
     83             throws NoSuchAlgorithmException {
     84         Provider.Service serv;
     85 
     86         if (algorithm == null) {
     87             throw new NoSuchAlgorithmException("Null algorithm name");
     88         }
     89         Services.refresh();
     90         if (returnedService != null
     91                 && Util.equalsIgnoreCase(algorithm, lastAlgorithm)
     92                 && refreshNumber == Services.refreshNumber) {
     93             serv = returnedService;
     94         } else {
     95             if (Services.isEmpty()) {
     96                 throw notFound(serviceName, algorithm);
     97             }
     98             serv = Services.getService(new StringBuilder(128)
     99                     .append(serviceName).append(".").append(
    100                             Util.toUpperCase(algorithm)).toString());
    101             if (serv == null) {
    102                 throw notFound(serviceName, algorithm);
    103             }
    104             returnedService = serv;
    105             lastAlgorithm = algorithm;
    106             refreshNumber = Services.refreshNumber;
    107         }
    108         spi = serv.newInstance(param);
    109         this.provider = serv.getProvider();
    110     }
    111 
    112     private NoSuchAlgorithmException notFound(String serviceName, String algorithm) throws NoSuchAlgorithmException {
    113         throw new NoSuchAlgorithmException(serviceName + " " + algorithm + " implementation not found");
    114     }
    115 
    116     /**
    117      *
    118      * Finds the appropriate service implementation and creates instance of the
    119      * class that implements corresponding Service Provider Interface.
    120      *
    121      * @param algorithm
    122      * @param service
    123      * @param provider
    124      * @throws NoSuchAlgorithmException
    125      */
    126     public synchronized void getInstance(String algorithm, Provider provider,
    127             Object param) throws NoSuchAlgorithmException {
    128 
    129         Provider.Service serv = null;
    130         if (algorithm == null) {
    131             throw new NoSuchAlgorithmException("algorithm == null");
    132         }
    133         serv = provider.getService(serviceName, algorithm);
    134         if (serv == null) {
    135             throw notFound(serviceName, algorithm);
    136         }
    137         spi = serv.newInstance(param);
    138         this.provider = provider;
    139     }
    140 
    141 }
    142