/**
 * <copyright> Copyright 2006 by Know-Center, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 */
package at.knowcenter.wag.egov.egiz.ldap.api;

import java.util.Hashtable;

import org.apache.log4j.Logger;

import at.knowcenter.wag.egov.egiz.ldap.client.LDAPIssuerNameFilter;
import at.knowcenter.wag.egov.egiz.sig.LDAPAPI;

/**
 * @author <a href="mailto:thomas.knall@iaik.tugraz.at">Thomas Knall</a>
 */
public class LDAPAPIFactoryImpl extends LDAPAPIFactory {

	private static final Logger log = Logger.getLogger(LDAPAPIFactoryImpl.class);

	// mapping <full qualified class name, LDAPAPI implementation>
//	private Hashtable<String, LDAPAPI> ldapImpls;
	private Hashtable ldapImpls;
	
	private LDAPIssuerNameFilter ldapIssuerNameFilter;
	
	protected LDAPAPIFactoryImpl(LDAPIssuerNameFilter ldapIssuerNameFilter) {
		this.ldapImpls = new Hashtable();
		this.ldapIssuerNameFilter = ldapIssuerNameFilter;
	}

	private LDAPAPI instantiatelAPIImpl(String implClassURI) throws LDAPAPIException {
		if (implClassURI == null) {
			throw new NullPointerException("URI of implementing class must not be null.");
		}
		if (implClassURI.length() == 0) {
			throw new IllegalArgumentException("URI of implementing class must not be empty.");
		}
		log.info("Trying to instantiate \"" + LDAPAPI.class.getName() + "\" implementation \"" + implClassURI + "\"...");
		LDAPAPI ldapAPIImpl = null;
		try {
			Class clazz = Class.forName(implClassURI);
			Object ldapAPIImplObj = clazz.newInstance();
			if (!(ldapAPIImplObj instanceof LDAPAPI)) {
				throw new LDAPAPIException("Declared class does not implement \""	+ LDAPAPI.class.getName() + "\".");
			}
			ldapAPIImpl = (LDAPAPI) ldapAPIImplObj;
			log.info("LDAPAPI implementation successfully instantiated.");
			ldapAPIImpl.setIssuerNameFilter(this.ldapIssuerNameFilter);
		} catch (InstantiationException e) {
			throw new LDAPAPIException("Declared implementation of \"" + LDAPAPI.class.getName() + "\" cannot be instantiated.");
		} catch (IllegalAccessException e) {
			throw new LDAPAPIException("Declared implementation of \"" + LDAPAPI.class.getName() + "\" cannot be instantiated (illegal access).");
		} catch (ClassNotFoundException e) {
			throw new LDAPAPIException("Unable to find class \"" + implClassURI + "\" as implementation of \"" + LDAPAPI.class.getName() + "\".");
		}
		return ldapAPIImpl;
	}
	
	public synchronized LDAPAPI createLDAPAPI(String implClassURI) throws LDAPAPIException {
		if (implClassURI == null || implClassURI.length() == 0) {
			// use internal implementation
			implClassURI = LDAPAPIImpl.class.getName();
		}
		LDAPAPI impl = (LDAPAPI) this.ldapImpls.get(implClassURI);
		if (impl == null) {
			impl = this.instantiatelAPIImpl(implClassURI);
			this.ldapImpls.put(implClassURI, impl);
		}
		return impl;
	}

}