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30 day Evaluation Version distributed via the Maven Jar Repository. Clover is not free. You have 30 days to evaluate it. Please visit http://www.thecortex.net/clover to obtain a licensed version of Clover | |||||||||||||||||||
Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
LoggingInterceptorFactory.java | 94.4% | 97.8% | 100% | 97.5% |
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// Copyright 2004 The Apache Software Foundation
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package org.apache.hivemind.service.impl;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.Modifier;
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import java.util.Iterator;
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import java.util.List;
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import org.apache.commons.logging.Log;
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import org.apache.hivemind.ApplicationRuntimeException;
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import org.apache.hivemind.InterceptorStack;
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import org.apache.hivemind.ServiceInterceptorFactory;
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import org.apache.hivemind.internal.Module;
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import org.apache.hivemind.methodmatch.MethodMatcher;
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import org.apache.hivemind.service.BodyBuilder;
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import org.apache.hivemind.service.ClassFab;
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import org.apache.hivemind.service.ClassFabUtils;
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import org.apache.hivemind.service.ClassFactory;
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import org.apache.hivemind.service.MethodContribution;
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import org.apache.hivemind.service.MethodFab;
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import org.apache.hivemind.service.MethodIterator;
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import org.apache.hivemind.service.MethodSignature;
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/**
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* An interceptor factory that adds logging capability to a service. The logging
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* is based upon the Jakarta <a
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* href="http://jakarta.apache.org/commons/logging.html">commons-logging </a>
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* toolkit, which makes it very transportable.
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* <p>
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* The interceptor will log entry to each method and exit from the method (with
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* return value), plus log any exceptions thrown by the method. The logger used
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* is the <em>id of the service</em>, which is not necessarily the name of
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* the implementing class. Logging occurs at the debug level.
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*
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* @author Howard Lewis Ship
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*/
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public class LoggingInterceptorFactory implements ServiceInterceptorFactory |
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{ |
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private ClassFactory _factory;
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private String _serviceId;
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/**
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* Creates a method that delegates to the _inner object; this is used for
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* methods that are not logged.
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*/
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private void addPassThruMethodImplementation(ClassFab classFab, MethodSignature sig) |
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{ |
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BodyBuilder builder = new BodyBuilder();
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builder.begin(); |
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builder.add("return ($r) _inner.");
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builder.add(sig.getName()); |
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builder.addln("($$);");
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builder.end(); |
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classFab.addMethod(Modifier.PUBLIC, sig, builder.toString()); |
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} |
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protected void addServiceMethodImplementation(ClassFab classFab, MethodSignature sig) |
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{ |
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Class returnType = sig.getReturnType(); |
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String methodName = sig.getName(); |
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boolean isVoid = (returnType == void.class); |
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BodyBuilder builder = new BodyBuilder();
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builder.begin(); |
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builder.addln("boolean debug = _log.isDebugEnabled();");
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builder.addln("if (debug)");
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builder.add(" org.apache.hivemind.service.impl.LoggingUtils.entry(_log, ");
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builder.addQuoted(methodName); |
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builder.addln(", $args);");
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if (!isVoid)
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{ |
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builder.add(ClassFabUtils.getJavaClassName(returnType)); |
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builder.add(" result = ");
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} |
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builder.add("_inner.");
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builder.add(methodName); |
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builder.addln("($$);");
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if (isVoid)
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{ |
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builder.addln("if (debug)");
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builder.add(" org.apache.hivemind.service.impl.LoggingUtils.voidExit(_log, ");
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builder.addQuoted(methodName); |
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builder.addln(");");
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} |
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else
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{ |
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builder.addln("if (debug)");
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builder.add(" org.apache.hivemind.service.impl.LoggingUtils.exit(_log, ");
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builder.addQuoted(methodName); |
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builder.addln(", ($w)result);");
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builder.addln("return result;");
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} |
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builder.end(); |
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MethodFab methodFab = classFab.addMethod(Modifier.PUBLIC, sig, builder.toString()); |
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builder.clear(); |
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builder.begin(); |
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builder.add("org.apache.hivemind.service.impl.LoggingUtils.exception(_log, ");
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builder.addQuoted(methodName); |
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builder.addln(", $e);");
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builder.addln("throw $e;");
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builder.end(); |
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String body = builder.toString(); |
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Class[] exceptions = sig.getExceptionTypes(); |
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int count = exceptions.length;
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for (int i = 0; i < count; i++) |
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{ |
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methodFab.addCatch(exceptions[i], body); |
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} |
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// Catch and log any runtime exceptions, in addition to the
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// checked exceptions.
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methodFab.addCatch(RuntimeException.class, body);
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} |
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protected void addServiceMethods(InterceptorStack stack, ClassFab fab, List parameters) |
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{ |
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MethodMatcher matcher = buildMethodMatcher(parameters); |
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MethodIterator mi = new MethodIterator(stack.getServiceInterface());
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while (mi.hasNext())
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{ |
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MethodSignature sig = mi.next(); |
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if (includeMethod(matcher, sig))
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addServiceMethodImplementation(fab, sig); |
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else
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addPassThruMethodImplementation(fab, sig); |
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} |
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if (!mi.getToString())
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addToStringMethod(stack, fab); |
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} |
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/**
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* Creates a toString() method that identify the interceptor service id, the
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* intercepted service id, and the service interface class name).
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*/
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protected void addToStringMethod(InterceptorStack stack, ClassFab fab) |
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{ |
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ClassFabUtils.addToStringMethod(fab, "<LoggingInterceptor for " + stack.getServiceExtensionPointId() + "(" |
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+ stack.getServiceInterface().getName() + ")>");
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} |
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private MethodMatcher buildMethodMatcher(List parameters)
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{ |
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MethodMatcher result = null;
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Iterator i = parameters.iterator(); |
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while (i.hasNext())
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{ |
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MethodContribution mc = (MethodContribution) i.next(); |
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if (result == null) |
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result = new MethodMatcher();
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result.put(mc.getMethodPattern(), mc); |
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} |
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return result;
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} |
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private Class constructInterceptorClass(InterceptorStack stack, List parameters)
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{ |
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Class serviceInterfaceClass = stack.getServiceInterface(); |
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Module module = stack.getServiceModule(); |
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String name = ClassFabUtils.generateClassName("Interceptor");
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ClassFab classFab = _factory.newClass(name, Object.class, module.getClassResolver().getClassLoader());
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classFab.addInterface(serviceInterfaceClass); |
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createInfrastructure(stack, classFab); |
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addServiceMethods(stack, classFab, parameters); |
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return classFab.createClass();
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} |
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private void createInfrastructure(InterceptorStack stack, ClassFab classFab) |
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{ |
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Class topClass = ClassFabUtils.getInstanceClass(stack.peek(), stack.getServiceInterface()); |
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classFab.addField("_log", Log.class); |
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// This is very important: since we know the instance of the top object
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// (the next
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// object in the pipeline for this service), we can build the instance
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// variable
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// and constructor to use the exact class rather than the service
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// interface.
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// That's more efficient at runtime, lowering the cost of using
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// interceptors.
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// One of the reasons I prefer Javassist over JDK Proxies.
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classFab.addField("_inner", topClass);
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classFab.addConstructor(new Class[]
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{ Log.class, topClass }, null, "{ _log = $1; _inner = $2; }"); |
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} |
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/**
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* Creates the interceptor. The class that is created is cached; if an
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* interceptor is requested for the same extension point, then the
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* previously constructed class is reused (this can happen with the threaded
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* service model, for example, when a thread-local service implementation is
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* created for different threads).
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*/
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public void createInterceptor(InterceptorStack stack, Module contributingModule, List parameters) |
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{ |
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Class interceptorClass = constructInterceptorClass(stack, parameters); |
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try
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{ |
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Object interceptor = instantiateInterceptor(stack, interceptorClass); |
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stack.push(interceptor); |
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} |
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catch (Exception ex)
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{ |
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throw new ApplicationRuntimeException(ServiceMessages.errorInstantiatingInterceptor(_serviceId, stack, |
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interceptorClass, ex), ex); |
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} |
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} |
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private boolean includeMethod(MethodMatcher matcher, MethodSignature sig) |
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{ |
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if (matcher == null) |
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return true; |
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MethodContribution mc = (MethodContribution) matcher.get(sig); |
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return mc == null || mc.getInclude(); |
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} |
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private Object instantiateInterceptor(InterceptorStack stack, Class interceptorClass) throws Exception |
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{ |
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Object stackTop = stack.peek(); |
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Constructor c = interceptorClass.getConstructors()[0]; |
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return c.newInstance(new Object[] |
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{ stack.getServiceLog(), stackTop }); |
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} |
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public void setFactory(ClassFactory factory) |
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{ |
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_factory = factory; |
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} |
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public void setServiceId(String string) |
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{ |
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_serviceId = string; |
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} |
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} |
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