AbstractServiceServlet.java

package azkaban.webapp.servlet;

import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.codehaus.jackson.map.ObjectMapper;
import azkaban.webapp.AzkabanServer;

public class AbstractServiceServlet extends HttpServlet{
	
	private static final long serialVersionUID = 1L;
	public static final String JSON_MIME_TYPE = "application/json";
	
	private AzkabanServer application;

	@Override
	public void init(ServletConfig config) throws ServletException {
		application = (AzkabanServer) config.getServletContext().getAttribute(AzkabanServletContextListener.AZKABAN_SERVLET_CONTEXT_KEY);

		if (application == null) {
			throw new IllegalStateException(
					"No batch application is defined in the servlet context!");
		}
	}

	protected void writeJSON(HttpServletResponse resp, Object obj) throws IOException {
		resp.setContentType(JSON_MIME_TYPE);
		ObjectMapper mapper = new ObjectMapper();
		OutputStream stream = resp.getOutputStream();
		mapper.writeValue(stream, obj);
	}

	public boolean hasParam(HttpServletRequest request, String param) {
		return request.getParameter(param) != null;
	}

	public String getParam(HttpServletRequest request, String name)
			throws ServletException {
		String p = request.getParameter(name);
		if (p == null)
			throw new ServletException("Missing required parameter '" + name + "'.");
		else
			return p;
	}
	
	public String getParam(HttpServletRequest request, String name, String defaultVal ) {
		String p = request.getParameter(name);
		if (p == null) {
			return defaultVal;
		}

		return p;
	}

	public int getIntParam(HttpServletRequest request, String name) throws ServletException {
		String p = getParam(request, name);
		return Integer.parseInt(p);
	}
	
	public int getIntParam(HttpServletRequest request, String name, int defaultVal) {
		if (hasParam(request, name)) {
			try {
				return getIntParam(request, name);
			} catch (Exception e) {
				return defaultVal;
			}
		}
		return defaultVal;
	}
	
	public long getLongParam(HttpServletRequest request, String name) throws ServletException {
		String p = getParam(request, name);
		return Long.parseLong(p);
	}
	
	public long getLongParam(HttpServletRequest request, String name, long defaultVal) {
		if (hasParam(request, name)) {
			try {
				return getLongParam(request, name);
			} catch (Exception e) {
				return defaultVal;
			}
		}
		return defaultVal;
	}
	
}