MySimpleTag.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2013-2017 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://oss.oracle.com/licenses/CDDL+GPL-1.1
 * or LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package mypack;

import java.io.IOException;
import java.io.StringWriter;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.JspFragment;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;


public class MySimpleTag extends SimpleTagSupport {
	
  private boolean pConstructed = false;
  private PageContext pageContext;

  public void doTag() {

    this.pageContext = (PageContext) getJspContext();
    if (pConstructed) {
        pageContext.setAttribute("InjectMessage", "==PostConstruct==");
    }
    JspWriter out = pageContext.getOut();
    StringWriter sw = new StringWriter();
    try {
      JspFragment body = getJspBody();
      body.invoke(sw);
      out.println(sw.toString());
    } catch (IOException | JspException e) {
      e.printStackTrace();
    }
  }

  @PostConstruct
  public void myPostConstruct () {
     pConstructed = true;
  }

  @PreDestroy
  public void myPreDestroy () {
      pageContext.setAttribute("InjectMessage", "==PreDestroy==");
  }
}