Java tutorial
/* * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. 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. 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For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ package org.apache.jk.common; import java.io.IOException; import javax.management.ObjectName; import org.apache.commons.modeler.Registry; import org.apache.jk.apr.AprImpl; import org.apache.jk.core.JkHandler; import org.apache.jk.core.Msg; import org.apache.jk.core.MsgContext; import org.apache.tomcat.util.buf.ByteChunk; import org.apache.tomcat.util.buf.C2BConverter; import org.apache.tomcat.util.buf.MessageBytes; /** * Base class for components using native code ( libjkjni.so ). * It allows to access the jk_env and wrap ( 'box' ? ) a native * jk component, and call it's methods. * * Note that get/setAttribute are expensive ( Strings, etc ), * invoke() is were all optimizations are done. We do recycle * all memory on both C and java sides ( the only exception is * when we attempt pinning but the VM doesn't support it ). The * low level optimizations from ByteBuffer, etc are used to * reduce the overhead of passing strings. * * @author Costin Manolache */ public class JniHandler extends JkHandler { protected AprImpl apr; // The native side handler protected long nativeJkHandlerP; protected String jkHome; // Dispatch table codes. Hardcoded for now, will change when we have more handlers. public static final int JK_HANDLE_JNI_DISPATCH = 0x15; public static final int JK_HANDLE_SHM_DISPATCH = 0x16; public static final int MSG_NOTE = 0; public static final int C2B_NOTE = 1; public static final int MB_NOTE = 2; public JniHandler() { } /** */ public void setJkHome(String s) { jkHome = s; } public String getJkHome() { return jkHome; } /** You must call initNative() inside the component init() */ public void init() throws IOException { // static field init, temp } protected void initNative(String nativeComponentName) { apr = (AprImpl) wEnv.getHandler("apr"); if (apr == null) { // In most cases we can just load it automatically. // that requires all libs to be installed in standard places // ( LD_LIBRARY_PATH, /usr/lib try { apr = new AprImpl(); wEnv.addHandler("apr", apr); apr.init(); if (oname != null) { ObjectName aprname = new ObjectName(oname.getDomain() + ":type=JkHandler, name=apr"); Registry.getRegistry().registerComponent(apr, aprname, null); } } catch (Throwable t) { log.debug("Can't load apr", t); apr = null; } } if (apr == null || !apr.isLoaded()) { if (log.isDebugEnabled()) log.debug("No apr, disabling jni proxy "); apr = null; return; } try { long xEnv = apr.getJkEnv(); nativeJkHandlerP = apr.getJkHandler(xEnv, nativeComponentName); if (nativeJkHandlerP == 0) { log.debug("Component not found, creating it " + nativeComponentName); nativeJkHandlerP = apr.createJkHandler(xEnv, nativeComponentName); } log.debug("Native proxy " + nativeJkHandlerP); apr.releaseJkEnv(xEnv); } catch (Throwable t) { apr = null; log.info("Error calling apr ", t); } } public void appendString(Msg msg, String s, C2BConverter charsetDecoder) throws IOException { ByteChunk bc = charsetDecoder.getByteChunk(); charsetDecoder.recycle(); charsetDecoder.convert(s); charsetDecoder.flushBuffer(); msg.appendByteChunk(bc); } /** Create a msg context to be used with the shm channel */ public MsgContext createMsgContext() { if (nativeJkHandlerP == 0 || apr == null) return null; try { MsgContext msgCtx = new MsgContext(); MsgAjp msg = new MsgAjp(); msgCtx.setSource(this); msgCtx.setWorkerEnv(wEnv); msgCtx.setNext(this); msgCtx.setMsg(MSG_NOTE, msg); // XXX Use noteId C2BConverter c2b = new C2BConverter("UTF8"); msgCtx.setNote(C2B_NOTE, c2b); MessageBytes tmpMB = new MessageBytes(); msgCtx.setNote(MB_NOTE, tmpMB); return msgCtx; } catch (Exception ex) { ex.printStackTrace(); return null; } } public void setNativeAttribute(String name, String val) throws IOException { if (apr == null) return; if (nativeJkHandlerP == 0) { log.error("Unitialized component " + name + " " + val); return; } long xEnv = apr.getJkEnv(); apr.jkSetAttribute(xEnv, nativeJkHandlerP, name, val); apr.releaseJkEnv(xEnv); } public void initJkComponent() throws IOException { if (apr == null) return; if (nativeJkHandlerP == 0) { log.error("Unitialized component "); return; } long xEnv = apr.getJkEnv(); apr.jkInit(xEnv, nativeJkHandlerP); apr.releaseJkEnv(xEnv); } public void destroyJkComponent() throws IOException { if (apr == null) return; if (nativeJkHandlerP == 0) { log.error("Unitialized component "); return; } long xEnv = apr.getJkEnv(); apr.jkDestroy(xEnv, nativeJkHandlerP); apr.releaseJkEnv(xEnv); } protected void setNativeEndpoint(MsgContext msgCtx) { long xEnv = apr.getJkEnv(); msgCtx.setJniEnv(xEnv); long epP = apr.createJkHandler(xEnv, "endpoint"); log.debug("create ep " + epP); if (epP == 0) return; apr.jkInit(xEnv, epP); msgCtx.setJniContext(epP); } protected void recycleNative(MsgContext ep) { apr.jkRecycle(ep.getJniEnv(), ep.getJniContext()); } /** send and get the response in the same buffer. This calls the * method on the wrapped jk_bean object. */ protected int nativeDispatch(Msg msg, MsgContext ep, int code, int raw) throws IOException { if (log.isDebugEnabled()) log.debug("Sending packet " + code + " " + raw); if (raw == 0) { msg.end(); if (log.isTraceEnabled()) msg.dump("OUT:"); } // Create ( or reuse ) the jk_endpoint ( the native pair of // MsgContext ) long xEnv = ep.getJniEnv(); long nativeContext = ep.getJniContext(); if (nativeContext == 0 || xEnv == 0) { setNativeEndpoint(ep); xEnv = ep.getJniEnv(); nativeContext = ep.getJniContext(); } if (xEnv == 0 || nativeContext == 0 || nativeJkHandlerP == 0) { log.error("invokeNative: Null pointer "); return -1; } // Will process the message in the current thread. // No wait needed to receive the response, if any int status = apr.jkInvoke(xEnv, nativeJkHandlerP, nativeContext, code, msg.getBuffer(), 0, msg.getLen(), raw); if (status != 0 && status != 2) { log.error("nativeDispatch: error " + status, new Throwable()); } if (log.isDebugEnabled()) log.debug("Sending packet - done " + status); return status; } /** Base implementation for invoke. Dispatch the action to the native * code, where invoke() is called on the wrapped jk_bean. */ public int invoke(Msg msg, MsgContext ep) throws IOException { long xEnv = ep.getJniEnv(); int type = ep.getType(); int status = nativeDispatch(msg, ep, type, 0); apr.jkRecycle(xEnv, ep.getJniContext()); apr.releaseJkEnv(xEnv); return status; } private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(JniHandler.class); }