1 files changed, 118 insertions, 0 deletions
diff --git a/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/springweb/AbstractAuthSourceServlet.java b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/springweb/AbstractAuthSourceServlet.java
new file mode 100644
index 00000000..095c3439
--- /dev/null
+++ b/eaaf_core/src/main/java/at/gv/egiz/eaaf/core/impl/idp/process/springweb/AbstractAuthSourceServlet.java
@@ -0,0 +1,118 @@
+/*******************************************************************************
+ *******************************************************************************/
+package at.gv.egiz.eaaf.core.impl.idp.process.springweb;
+
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
+import org.springframework.web.context.WebApplicationContext;
+import org.springframework.web.context.support.WebApplicationContextUtils;
+
+import at.gv.egiz.eaaf.core.api.idp.process.ExecutionContext;
+import at.gv.egiz.eaaf.core.api.idp.process.ProcessEngine;
+import at.gv.egiz.eaaf.core.impl.idp.process.ProcessInstance;
+
+/**
+ * Abstract HttpServlet that provides means for retrieving the process engine (Spring Web required) as well as
+ * retrieving the underlying process instance and execution context evaluating a certain request parameter.
+ * 
+ * @author tknall
+ * 
+ */
+public abstract class AbstractAuthSourceServlet extends HttpServlet {
+
+	private static final long serialVersionUID = 1L;
+
+	private ProcessEngine processEngine;
+	
+	/**
+	 * Returns the name of the request parameter representing the respective instance id.
+	 * <p/>Default is {@code processInstanceId}.
+	 * @return The request parameter name.
+	 */
+	public String getProcessInstanceIdParameterName() {
+		return "processInstanceId";
+	}
+
+	/**
+	 * Returns the underlying process engine instance.
+	 * 
+	 * @return The process engine (never {@code null}).
+	 * @throws NoSuchBeanDefinitionException
+	 *             if no {@link ProcessEngine} bean was found.
+	 * @throws NoUniqueBeanDefinitionException
+	 *             if more than one {@link ProcessEngine} bean was found.
+	 * @throws BeansException
+	 *             if a problem getting the {@link ProcessEngine} bean occurred.
+	 * @throws IllegalStateException
+	 *             if the Spring WebApplicationContext was not found, which means that the servlet is used outside a
+	 *             Spring web environment.
+	 */
+	public synchronized ProcessEngine getProcessEngine() {
+		if (processEngine == null) {
+			WebApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(getServletContext());
+			if (ctx == null) {
+				throw new IllegalStateException(
+						"Unable to find Spring WebApplicationContext. Servlet needs to be executed within a Spring web environment.");
+			}
+			processEngine = ctx.getBean(ProcessEngine.class);
+		}
+		return processEngine;
+	}
+
+	/**
+	 * Retrieves the process instance referenced by the request parameter {@link #getProcessInstanceIdParameterName()}.
+	 * 
+	 * @param request
+	 *            The HttpServletRequest.
+	 * @return The process instance (never {@code null}).
+	 * @throws NoSuchBeanDefinitionException
+	 *             if no {@link ProcessEngine} bean was found.
+	 * @throws NoUniqueBeanDefinitionException
+	 *             if more than one {@link ProcessEngine} bean was found.
+	 * @throws BeansException
+	 *             if a problem getting the {@link ProcessEngine} bean occurred.
+	 * @throws IllegalStateException
+	 *             if the Spring WebApplicationContext was not found, which means that the servlet is used outside a
+	 *             Spring web environment.
+	 * @throws IllegalArgumentException
+	 *             in case the process instance id referenced by the request parameter
+	 *             {@link #getProcessInstanceIdParameterName()} does not exist.
+	 */
+	public ProcessInstance getProcessInstance(HttpServletRequest request) {
+		String processInstanceId = StringUtils.trimToNull(request.getParameter(getProcessInstanceIdParameterName()));
+		if (processInstanceId == null) {
+			throw new IllegalArgumentException("Missing request parameter '" + getProcessInstanceIdParameterName() + "'.");
+		}
+		return getProcessEngine().getProcessInstance(processInstanceId);
+	}
+
+	/**
+	 * Retrieves the execution context for the respective process instance referenced by the request parameter
+	 * {@link #getProcessInstanceIdParameterName()}.
+	 * 
+	 * @param request
+	 *            The HttpServletRequest.
+	 * @return The execution context (never {@code null}).
+	 * @throws NoSuchBeanDefinitionException
+	 *             if no {@link ProcessEngine} bean was found.
+	 * @throws NoUniqueBeanDefinitionException
+	 *             if more than one {@link ProcessEngine} bean was found.
+	 * @throws BeansException
+	 *             if a problem getting the {@link ProcessEngine} bean occurred.
+	 * @throws IllegalStateException
+	 *             if the Spring WebApplicationContext was not found, which means that the servlet is used outside a
+	 *             Spring web environment.
+	 * @throws IllegalArgumentException
+	 *             in case the process instance id referenced by the request parameter
+	 *             {@link #getProcessInstanceIdParameterName()} does not exist.
+	 */
+	public ExecutionContext getExecutionContext(HttpServletRequest request) {
+		return getProcessInstance(request).getExecutionContext();
+	}
+
+}