//
// ========================================================================
// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under
// the terms of the Eclipse Public License 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0
//
// This Source Code may also be made available under the following
// Secondary Licenses when the conditions for such availability set
// forth in the Eclipse Public License, v. 2.0 are satisfied:
// the Apache License v2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//

package org.eclipse.jetty.server.handler;

import java.io.IOException;
import java.util.Arrays;
import java.util.List;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.HandlerContainer;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.component.LifeCycle;

A HandlerWrapper acts as a Handler but delegates the handle method and life cycle events to a delegate. This is primarily used to implement the Decorator pattern.
/** * A <code>HandlerWrapper</code> acts as a {@link Handler} but delegates the {@link Handler#handle handle} method and * {@link LifeCycle life cycle} events to a delegate. This is primarily used to implement the <i>Decorator</i> pattern. */
@ManagedObject("Handler wrapping another Handler") public class HandlerWrapper extends AbstractHandlerContainer { protected Handler _handler; /** * */ public HandlerWrapper() { }
Returns:Returns the handlers.
/** * @return Returns the handlers. */
@ManagedAttribute(value = "Wrapped Handler", readonly = true) public Handler getHandler() { return _handler; }
Returns:Returns the handlers.
/** * @return Returns the handlers. */
@Override public Handler[] getHandlers() { if (_handler == null) return new Handler[0]; return new Handler[]{_handler}; }
Params:
  • handler – Set the Handler which should be wrapped.
/** * @param handler Set the {@link Handler} which should be wrapped. */
public void setHandler(Handler handler) { if (isStarted()) throw new IllegalStateException(getState()); // check for loops if (handler == this || (handler instanceof HandlerContainer && Arrays.asList(((HandlerContainer)handler).getChildHandlers()).contains(this))) throw new IllegalStateException("setHandler loop"); if (handler != null) handler.setServer(getServer()); Handler old = _handler; _handler = handler; updateBean(old, _handler, true); }
Replace the current handler with another HandlerWrapper linked to the current handler.

This is equivalent to:

  wrapper.setHandler(getHandler());
  setHandler(wrapper);
Params:
  • wrapper – the wrapper to insert
/** * Replace the current handler with another HandlerWrapper * linked to the current handler. * <p> * This is equivalent to: * <pre> * wrapper.setHandler(getHandler()); * setHandler(wrapper); * </pre> * * @param wrapper the wrapper to insert */
public void insertHandler(HandlerWrapper wrapper) { if (wrapper == null) throw new IllegalArgumentException(); HandlerWrapper tail = wrapper; while (tail.getHandler() instanceof HandlerWrapper) { tail = (HandlerWrapper)tail.getHandler(); } if (tail.getHandler() != null) throw new IllegalArgumentException("bad tail of inserted wrapper chain"); Handler next = getHandler(); setHandler(wrapper); tail.setHandler(next); } @Override public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { Handler handler = _handler; if (handler != null) handler.handle(target, baseRequest, request, response); } @Override protected void expandChildren(List<Handler> list, Class<?> byClass) { expandHandler(_handler, list, byClass); } @Override public void destroy() { if (!isStopped()) throw new IllegalStateException("!STOPPED"); Handler child = getHandler(); if (child != null) { setHandler(null); child.destroy(); } super.destroy(); } }