header.java

图书馆检索系统

package tags;

import java.io.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;

public class Header extends TagSupport {
  private final int SKIP_SEARCH = 0;
  private final int SKIP_MEMBER = 1;
  private final int SKIP_LIBRARIAN = 2;
  private final String SEP = "    ||    ";
  private int omit = -1;

  public int getOmit() {
    return omit;
  }

  public void setOmit(int omit) {
    this.omit = omit;
  }

  public int doStartTag() throws JspException {
    String search = (getOmit() == SKIP_SEARCH) 
                  ? "Search"
                  : "<a href=\"index.jsp\">Search</a>";
    String member = (getOmit() == SKIP_MEMBER)
                  ? "Member Login"
                  : "<a href=\"member.jsp\">Member Login</a>";
    String librarian = (getOmit() == SKIP_LIBRARIAN)
                     ? "Librarian Login"
                     : "<a href=\"librarian.jsp\">Librarian Login</a>";

    try {
      pageContext.getOut().println("<img src=\"/library/images/logo.gif\" class=\"logo\">\n\n"
              + "    <div class=\"center\" style=\"width: 600\">\n"
              + "      <b class=\"smaller\">\n"
              + "        " + search + SEP + member + SEP + librarian + "\n"
              + "      </b>\n"
              + "    </div>");
    } catch (IOException ioe) {
      throw new JspException(ioe);
    }

    return SKIP_BODY;
  }
}