src/org/apache/xml/security/keys/keyresolver/KeyResolverSpi.java

/*
 * Copyright  1999-2004 The Apache Software Foundation.
 *
 *  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.apache.xml.security.keys.keyresolver;



import java.security.PublicKey;
import java.security.cert.X509Certificate;

import javax.crypto.SecretKey;

import org.apache.xml.security.keys.storage.StorageResolver;
import org.w3c.dom.Element;


/**
 * This class is abstract class for a child KeyInfo Elemnet.
 *
 * If you want the your KeyResolver, at firstly you must extand this class, and register
 * as following in config.xml
 * <PRE>
 *  &lt;KeyResolver URI="http://www.w3.org/2000/09/xmldsig#KeyValue"
 *   JAVACLASS="MyPackage.MyKeyValueImpl"//gt;
 * </PRE>
 *
 * @author $Author$
 * @version $Revision$
 */
public abstract class KeyResolverSpi {

   /** {@link org.apache.commons.logging} logging facility */
    static org.apache.commons.logging.Log log = 
        org.apache.commons.logging.LogFactory.getLog(KeyResolverSpi.class.getName());

   /**
    * This method helps the {@link org.apache.xml.security.utils.resolver.ResourceResolver} to decide whether a
    * {@link org.apache.xml.security.utils.resolver.ResourceResolverSpi} is able to perform the requested action.
    *
    * @param element
    * @param BaseURI
    * @param storage
    * @return true if can resolve the key in the element
    */
   abstract public boolean engineCanResolve(Element element, String BaseURI,
                                            StorageResolver storage);

   /**
    * Method engineResolvePublicKey
    *
    * @param element
    * @param BaseURI
    * @param storage
    * @return resolved public key from the registered from the element.
    * 
    * @throws KeyResolverException
    */
   abstract public PublicKey engineResolvePublicKey(
      Element element, String BaseURI, StorageResolver storage)
         throws KeyResolverException;

   /**
    * Method engineResolveCertificate
    *
    * @param element
    * @param BaseURI
    * @param storage
    * @return resolved X509Certificate key from the registered from the elements
    *
    * @throws KeyResolverException
    */
   abstract public X509Certificate engineResolveX509Certificate(
      Element element, String BaseURI, StorageResolver storage)
         throws KeyResolverException;

   /**
    * Method engineResolveSecretKey
    *
    * @param element
    * @param BaseURI
    * @param storage
    * @return resolved SecretKey key from the registered from the elements
    *
    * @throws KeyResolverException
    */
   abstract public SecretKey engineResolveSecretKey(
      Element element, String BaseURI, StorageResolver storage)
         throws KeyResolverException;

   /** Field _properties */
   protected java.util.Map _properties = new java.util.HashMap(10);

   /**
    * Method engineSetProperty
    *
    * @param key
    * @param value
    */
   public void engineSetProperty(String key, String value) {

      java.util.Iterator i = this._properties.keySet().iterator();

      while (i.hasNext()) {
         String c = (String) i.next();

         if (c.equals(key)) {
            key = c;

            break;
         }
      }

      this._properties.put(key, value);
   }

   /**
    * Method engineGetProperty
    *
    * @param key
    * @return obtain the property appointed by key
    */
   public String engineGetProperty(String key) {

      java.util.Iterator i = this._properties.keySet().iterator();

      while (i.hasNext()) {
         String c = (String) i.next();

         if (c.equals(key)) {
            key = c;

            break;
         }
      }

      return (String) this._properties.get(key);
   }

   /**
    * Method engineGetPropertyKeys
    *
    * @return the keys of properties known by this resolver
    */
   public String[] engineGetPropertyKeys() {
      return new String[0];
   }

   /**
    * Method understandsProperty
    *
    * @param propertyToTest
    * @return true if understood the property
    */
   public boolean understandsProperty(String propertyToTest) {

      String[] understood = this.engineGetPropertyKeys();

      if (understood != null) {
         for (int i = 0; i < understood.length; i++) {
            if (understood[i].equals(propertyToTest)) {
               return true;
            }
         }
      }

      return false;
   }
}