/**
    * Copyright 2005-2011 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.rice.ksb.security;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.security.Signature;
  
  import javax.servlet.ServletOutputStream;
  import javax.servlet.http.HttpServletResponse;
  import javax.servlet.http.HttpServletResponseWrapper;
  
  import org.kuali.rice.ksb.service.KSBServiceLocator;
  
  /**
   * An HttpServletResponseWrapper which wraps the underlying response's OutputStream in a 
   * SignatureSingingOutputStream which will generate a digital signature for the outgoing message.
   *  
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class SignatureSigningResponseWrapper extends HttpServletResponseWrapper {
  
  	private DigitalSigner signer;
  	private ServletOutputStream outputStream;
  	private PrintWriter writer;
  	
  	public SignatureSigningResponseWrapper(HttpServletResponse response) {
  		super(response);
  		try {		
  			Signature signature = KSBServiceLocator.getDigitalSignatureService().getSignatureForSigning();
  			String alias = KSBServiceLocator.getJavaSecurityManagementService().getModuleKeyStoreAlias();	
  			this.signer = new ResponseHeaderDigitalSigner(signature, alias, response);
  		} catch (Exception e) {
  			throw new RuntimeException("Failed to initialize digital signature verification.", e);
  		}
  	}
  
  	@Override
  	public ServletOutputStream getOutputStream() throws IOException {
  		if (this.outputStream == null) {
  		    this.outputStream = new SignatureSigningOutputStream(this.signer, super.getOutputStream(), true);
  		}
  		return this.outputStream;
  	}
  
  	@Override
  	public PrintWriter getWriter() throws IOException {
  		if (this.writer == null) {
  		    this.writer =  new PrintWriter(getOutputStream());
  		}
  		return this.writer;
  	}
  	
  }