THRIFT-1608 Allow servlet to be supplied TProcessor and TProtocolFactory after the init() method has finished
Patch: Kiril Raychev
git-svn-id: https://svn.apache.org/repos/asf/thrift/trunk@1351848 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/java/src/org/apache/thrift/server/TExtensibleServlet.java b/lib/java/src/org/apache/thrift/server/TExtensibleServlet.java
new file mode 100644
index 0000000..6bb215a
--- /dev/null
+++ b/lib/java/src/org/apache/thrift/server/TExtensibleServlet.java
@@ -0,0 +1,152 @@
+package org.apache.thrift.server;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Map;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.thrift.TException;
+import org.apache.thrift.TProcessor;
+import org.apache.thrift.protocol.TProtocol;
+import org.apache.thrift.protocol.TProtocolFactory;
+import org.apache.thrift.transport.TIOStreamTransport;
+import org.apache.thrift.transport.TTransport;
+
+/**
+ * Servlet implementation class ThriftServer, that allows {@link TProcessor} and
+ * {@link TProtocolFactory} to be supplied after the {@link #init()} method has
+ * finished. <br>
+ * Subclasses must implement the abstract methods that return the TProcessor and
+ * two TProtocolFactory. Those methods are guaranteed to be called exactly once,
+ * and that {@link ServletContext} is available.
+ */
+public abstract class TExtensibleServlet extends HttpServlet {
+ private static final long serialVersionUID = 1L;
+
+ private TProcessor processor;
+
+ private TProtocolFactory inFactory;
+
+ private TProtocolFactory outFactory;
+
+ private Collection<Map.Entry<String, String>> customHeaders;
+
+ /**
+ * Returns the appropriate {@link TProcessor}. This will be called <b>once</b> just
+ * after the {@link #init()} method
+ *
+ * @return
+ */
+ protected abstract TProcessor getProcessor();
+
+ /**
+ * Returns the appropriate in {@link TProtocolFactory}. This will be called
+ * <b>once</b> just after the {@link #init()} method
+ *
+ * @return
+ */
+ protected abstract TProtocolFactory getInProtocolFactory();
+
+ /**
+ * Returns the appropriate out {@link TProtocolFactory}. This will be called
+ * <b>once</b> just after the {@link #init()} method
+ *
+ * @return
+ */
+ protected abstract TProtocolFactory getOutProtocolFactory();
+
+ @Override
+ public final void init(ServletConfig config) throws ServletException {
+ super.init(config); //no-args init() happens here
+ this.processor = getProcessor();
+ this.inFactory = getInProtocolFactory();
+ this.outFactory = getOutProtocolFactory();
+ this.customHeaders = new ArrayList<Map.Entry<String, String>>();
+
+ if (processor == null) {
+ throw new ServletException("processor must be set");
+ }
+ if (inFactory == null) {
+ throw new ServletException("inFactory must be set");
+ }
+ if (outFactory == null) {
+ throw new ServletException("outFactory must be set");
+ }
+ }
+
+ /**
+ * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
+ * response)
+ */
+ @Override
+ protected void doPost(HttpServletRequest request, HttpServletResponse response)
+ throws ServletException, IOException {
+ TTransport inTransport = null;
+ TTransport outTransport = null;
+
+ try {
+ response.setContentType("application/x-thrift");
+
+ if (null != this.customHeaders) {
+ for (Map.Entry<String, String> header : this.customHeaders) {
+ response.addHeader(header.getKey(), header.getValue());
+ }
+ }
+
+ InputStream in = request.getInputStream();
+ OutputStream out = response.getOutputStream();
+
+ TTransport transport = new TIOStreamTransport(in, out);
+ inTransport = transport;
+ outTransport = transport;
+
+ TProtocol inProtocol = inFactory.getProtocol(inTransport);
+ TProtocol outProtocol = inFactory.getProtocol(outTransport);
+
+ processor.process(inProtocol, outProtocol);
+ out.flush();
+ } catch (TException te) {
+ throw new ServletException(te);
+ }
+ }
+
+ /**
+ * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
+ * response)
+ */
+ @Override
+ protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+ throws ServletException, IOException {
+ doPost(req, resp);
+ }
+
+ public void addCustomHeader(final String key, final String value) {
+ this.customHeaders.add(new Map.Entry<String, String>() {
+ public String getKey() {
+ return key;
+ }
+
+ public String getValue() {
+ return value;
+ }
+
+ public String setValue(String value) {
+ return null;
+ }
+ });
+ }
+
+ public void setCustomHeaders(Collection<Map.Entry<String, String>> headers) {
+ this.customHeaders.clear();
+ this.customHeaders.addAll(headers);
+ }
+}