Java tutorial
/* * The Apache Software License, Version 1.1 * * Copyright (c) 2001-2004 Caucho Technology, Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Caucho Technology (http://www.caucho.com/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "Hessian", "Resin", and "Caucho" must not be used to * endorse or promote products derived from this software without prior * written permission. For written permission, please contact * info@caucho.com. * * 5. Products derived from this software may not be called "Resin" * nor may "Resin" appear in their names without prior written * permission of Caucho Technology. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * @author Scott Ferguson */ package com.wills.clientproxy; import com.caucho.hessian.client.HessianConnection; import com.caucho.hessian.client.HessianRuntimeException; import com.caucho.hessian.io.*; import com.caucho.services.server.*; import java.io.*; import java.util.concurrent.locks.ReentrantLock; import java.util.concurrent.locks.ReentrantReadWriteLock; import java.util.logging.*; import java.lang.reflect.InvocationHandler; import java.lang.reflect.Method; import java.lang.reflect.Proxy; import java.util.WeakHashMap; import java.net.URL; import java.net.URLConnection; import org.apache.http.entity.ContentProducer; /** * HessianProxy,??? * @author huangsiping * */ public class HessianLBProxy implements InvocationHandler, Serializable { /** * */ private static final long serialVersionUID = 4178433512046319789L; private static final Logger log = Logger.getLogger(HessianLBProxy.class.getName()); protected HessianLBProxyFactory _factory; private WeakHashMap<Method, String> _mangleMap = new WeakHashMap<Method, String>(); private Class<?> _type; private ClusterNodeManager _cm; //private URL currentURL ; private ReentrantReadWriteLock lock = new ReentrantReadWriteLock(); private ThreadLocal<URL> threadLocal = new ThreadLocal<URL>(); public HessianLBProxy(ClusterNodeManager cm, HessianLBProxyFactory factory, Class<?> type) { _factory = factory; _cm = cm; _type = type; } /** * Handles the object invocation. * * @param proxy * the proxy object to invoke * @param method * the method to call * @param args * the arguments to the proxy object */ public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { String mangleName; HessianClusterNode hcn = _cm.getAvailableNodeByStraitegy(); if (hcn == null) { throw new Exception("no available server node found!"); } if (hcn == null || hcn.getNode() == null) { throw new Exception("no server available"); } threadLocal.set(new URL(hcn.getURL() + this._type.getSimpleName())); try { lock.readLock().lock(); mangleName = _mangleMap.get(method); } finally { lock.readLock().unlock(); } if (mangleName == null) { String methodName = method.getName(); Class<?>[] params = method.getParameterTypes(); // equals and hashCode are special cased if (methodName.equals("equals") && params.length == 1 && params[0].equals(Object.class)) { Object value = args[0]; if (value == null || !Proxy.isProxyClass(value.getClass())) return Boolean.FALSE; Object proxyHandler = Proxy.getInvocationHandler(value); if (!(proxyHandler instanceof HessianLBProxy)) return Boolean.FALSE; HessianLBProxy handler = (HessianLBProxy) proxyHandler; return new Boolean(false); } else if (methodName.equals("hashCode") && params.length == 0) return new Integer(_cm.hashCode()); else if (methodName.equals("getHessianType")) return proxy.getClass().getInterfaces()[0].getName(); else if (methodName.equals("getHessianURL")) return threadLocal.get().toString(); else if (methodName.equals("toString") && params.length == 0) return "HessianProxy[" + threadLocal.get() + "]"; if (!_factory.isOverloadEnabled()) mangleName = method.getName(); else mangleName = mangleName(method); try { lock.writeLock().lock(); _mangleMap.put(method, mangleName); } finally { lock.writeLock().unlock(); } } InputStream is = null; HessianConnection conn = null; try { if (log.isLoggable(Level.FINER)) log.finer("Hessian[" + threadLocal.get() + "] calling " + mangleName); conn = sendRequest(mangleName, args, threadLocal.get()); if (conn.getStatusCode() != 200) { throw new HessianProtocolException("http code is " + conn.getStatusCode()); } is = conn.getInputStream(); if (log.isLoggable(Level.FINEST)) { PrintWriter dbg = new PrintWriter(new LogWriter(log)); HessianDebugInputStream dIs = new HessianDebugInputStream(is, dbg); dIs.startTop2(); is = dIs; } AbstractHessianInput in; int code = is.read(); if (code == 'H') { int major = is.read(); int minor = is.read(); in = _factory.getHessian2Input(is); Object value = in.readReply(method.getReturnType()); return value; } else if (code == 'r') { int major = is.read(); int minor = is.read(); in = _factory.getHessianInput(is); in.startReplyBody(); Object value = in.readObject(method.getReturnType()); if (value instanceof InputStream) { value = new ResultInputStream(conn, is, in, (InputStream) value); is = null; conn = null; } else in.completeReply(); return value; } else throw new HessianProtocolException("'" + (char) code + "' is an unknown code"); } catch (HessianProtocolException e) { throw new HessianRuntimeException(e); } finally { try { if (is != null) is.close(); } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } try { if (conn != null) conn.destroy(); } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } } } protected String mangleName(Method method) { Class<?>[] param = method.getParameterTypes(); if (param == null || param.length == 0) return method.getName(); else return AbstractSkeleton.mangleName(method, false); } /** * Sends the HTTP request to the Hessian connection. */ protected HessianConnection sendRequest(final String methodName, final Object[] args, final URL currentUrl) throws IOException { HessianConnection conn = null; boolean isValid = false; try { conn = _factory.getConnectionFactory().open(currentUrl); addRequestHeaders(conn); ContentProducer contentProducer = new ContentProducer() { public void writeTo(OutputStream outstream) throws IOException { try { AbstractHessianOutput out = _factory.getHessianOutput(outstream); out.call(methodName, args); out.flush(); } catch (Exception e) { throw new HessianRuntimeException(e); } } }; conn.setContentProducer(contentProducer); conn.sendRequest(); isValid = true; } catch (Exception ex) { ex.printStackTrace(); } finally { if (!isValid && conn != null) conn.destroy(); } return conn; } /** * Method that allows subclasses to add request headers such as cookies. * Default implementation is empty. */ protected void addRequestHeaders(HessianConnection conn) { conn.addHeader("Content-Type", "x-application/hessian"); String basicAuth = _factory.getBasicAuth(); if (basicAuth != null) conn.addHeader("Authorization", basicAuth); } /** * Method that allows subclasses to parse response headers such as cookies. * Default implementation is empty. * * @param conn */ protected void parseResponseHeaders(URLConnection conn) { } public Object writeReplace() { return new HessianRemote(_type.getName(), threadLocal.get().toString()); } static class ResultInputStream extends InputStream { private HessianConnection _conn; private InputStream _connIs; private AbstractHessianInput _in; private InputStream _hessianIs; ResultInputStream(HessianConnection conn, InputStream is, AbstractHessianInput in, InputStream hessianIs) { _conn = conn; _connIs = is; _in = in; _hessianIs = hessianIs; } public int read() throws IOException { if (_hessianIs != null) { int value = _hessianIs.read(); if (value < 0) close(); return value; } else return -1; } public int read(byte[] buffer, int offset, int length) throws IOException { if (_hessianIs != null) { int value = _hessianIs.read(buffer, offset, length); if (value < 0) close(); return value; } else return -1; } public void close() throws IOException { HessianConnection conn = _conn; _conn = null; InputStream connIs = _connIs; _connIs = null; AbstractHessianInput in = _in; _in = null; InputStream hessianIs = _hessianIs; _hessianIs = null; try { if (hessianIs != null) hessianIs.close(); } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } try { if (in != null) { in.completeReply(); in.close(); } } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } try { if (connIs != null) { connIs.close(); } } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } try { if (conn != null) { conn.close(); } } catch (Exception e) { log.log(Level.FINE, e.toString(), e); } } } static class LogWriter extends Writer { private Logger _log; private Level _level = Level.FINEST; private StringBuilder _sb = new StringBuilder(); LogWriter(Logger log) { _log = log; } public void write(char ch) { if (ch == '\n' && _sb.length() > 0) { _log.fine(_sb.toString()); _sb.setLength(0); } else _sb.append((char) ch); } public void write(char[] buffer, int offset, int length) { for (int i = 0; i < length; i++) { char ch = buffer[offset + i]; if (ch == '\n' && _sb.length() > 0) { _log.log(_level, _sb.toString()); _sb.setLength(0); } else _sb.append((char) ch); } } public void flush() { } public void close() { if (_sb.length() > 0) _log.log(_level, _sb.toString()); } } }