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| 1 | /* | ||
| 2 | * Copyright (c) 2008, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package sun.tracing; | ||
| 27 | |||
| 28 | import java.lang.reflect.InvocationHandler; | ||
| 29 | import java.lang.reflect.Method; | ||
| 30 | import java.lang.reflect.Proxy; | ||
| 31 | import java.lang.reflect.InvocationTargetException; | ||
| 32 | import java.lang.reflect.AnnotatedElement; | ||
| 33 | import java.lang.annotation.Annotation; | ||
| 34 | import java.util.HashMap; | ||
| 35 | import java.security.AccessController; | ||
| 36 | import java.security.PrivilegedAction; | ||
| 37 | |||
| 38 | import com.sun.tracing.Provider; | ||
| 39 | import com.sun.tracing.Probe; | ||
| 40 | import com.sun.tracing.ProviderName; | ||
| 41 | |||
| 42 | /** | ||
| 43 | * Provides a common code for implementation of {@code Provider} classes. | ||
| 44 | * | ||
| 45 | * Each tracing subsystem needs to provide three classes, a factory | ||
| 46 | * (derived from {@code ProviderFactory}, a provider (a subclass of | ||
| 47 | * {@code Provider}, and a probe type (subclass of {@code ProbeSkeleton}). | ||
| 48 | * | ||
| 49 | * The factory object takes a user-defined interface and provides an | ||
| 50 | * implementation of it whose method calls will trigger probes in the | ||
| 51 | * tracing framework. | ||
| 52 | * | ||
| 53 | * The framework's provider class, and its instances, are not seen by the | ||
| 54 | * user at all -- they usually sit in the background and receive and dispatch | ||
| 55 | * the calls to the user's provider interface. The {@code ProviderSkeleton} | ||
| 56 | * class provides almost all of the implementation needed by a framework | ||
| 57 | * provider. Framework providers must only provide a constructor and | ||
| 58 | * disposal method, and implement the {@code createProbe} method to create | ||
| 59 | * an appropriate {@code ProbeSkeleton} subclass. | ||
| 60 | * | ||
| 61 | * The framework's probe class provides the implementation of the two | ||
| 62 | * probe methods, {@code isEnabled()} and {@code uncheckedTrigger()}. Both are | ||
| 63 | * framework-dependent implementations. | ||
| 64 | * | ||
| 65 | * @since 1.7 | ||
| 66 | */ | ||
| 67 | |||
| 68 | public abstract class ProviderSkeleton implements InvocationHandler, Provider { | ||
| 69 | |||
| 70 | protected boolean active; // set to false after dispose() is called | ||
| 71 | protected Class<? extends Provider> providerType; // user's interface | ||
| 72 | protected HashMap<Method, ProbeSkeleton> probes; // methods to probes | ||
| 73 | |||
| 74 | |||
| 75 | /** | ||
| 76 | * Creates a framework-specific probe subtype. | ||
| 77 | * | ||
| 78 | * This method is implemented by the framework's provider and returns | ||
| 79 | * framework-specific probes for a method. | ||
| 80 | * | ||
| 81 | * @param method A method in the user's interface | ||
| 82 | * @return a subclass of ProbeSkeleton for the particular framework. | ||
| 83 | */ | ||
| 84 | protected abstract ProbeSkeleton createProbe(Method method); | ||
| 85 | |||
| 86 | /** | ||
| 87 | * Initializes the provider. | ||
| 88 | * | ||
| 89 | * @param type the user's interface | ||
| 90 | */ | ||
| 91 | protected ProviderSkeleton(Class<? extends Provider> type) { | ||
| 92 | this.active = false; // in case of some error during initialization | ||
| 93 | this.providerType = type; | ||
| 94 | this.probes = new HashMap<Method,ProbeSkeleton>(); | ||
| 95 | } | ||
| 96 | |||
| 97 | /** | ||
| 98 | * Post-constructor initialization routine. | ||
| 99 | * | ||
| 100 | * Subclass instances must be initialized before they can create probes. | ||
| 101 | * It is up to the factory implementations to call this after construction. | ||
| 102 | */ | ||
| 103 | public void init() { | ||
| 104 | Method[] methods = AccessController.doPrivileged(new PrivilegedAction<Method[]>() { | ||
| 105 | public Method[] run() { | ||
| 106 | return providerType.getDeclaredMethods(); | ||
| 107 | } | ||
| 108 | }); | ||
| 109 | |||
| 110 | for (Method m : methods) { | ||
| 111 | if ( m.getReturnType() != Void.TYPE ) { | ||
| 112 | throw new IllegalArgumentException( | ||
| 113 | "Return value of method is not void"); | ||
| 114 | } else { | ||
| 115 | probes.put(m, createProbe(m)); | ||
| 116 | } | ||
| 117 | } | ||
| 118 | this.active = true; | ||
| 119 | } | ||
| 120 | |||
| 121 | /** | ||
| 122 | * Magic routine which creates an implementation of the user's interface. | ||
| 123 | * | ||
| 124 | * This method creates the instance of the user's interface which is | ||
| 125 | * passed back to the user. Every call upon that interface will be | ||
| 126 | * redirected to the {@code invoke()} method of this class (until | ||
| 127 | * overridden by the VM). | ||
| 128 | * | ||
| 129 | * @return an implementation of the user's interface | ||
| 130 | */ | ||
| 131 | @SuppressWarnings("unchecked") | ||
| 132 | public <T extends Provider> T newProxyInstance() { | ||
| 133 | return (T)Proxy.newProxyInstance(providerType.getClassLoader(), | ||
| 134 | new Class<?>[] { providerType }, this); | ||
| 135 | } | ||
| 136 | |||
| 137 | /** | ||
| 138 | * Triggers a framework probe when a user interface method is called. | ||
| 139 | * | ||
| 140 | * This method dispatches a user interface method call to the appropriate | ||
| 141 | * probe associated with this framework. | ||
| 142 | * | ||
| 143 | * If the invoked method is not a user-defined member of the interface, | ||
| 144 | * then it is a member of {@code Provider} or {@code Object} and we | ||
| 145 | * invoke the method directly. | ||
| 146 | * | ||
| 147 | * @param proxy the instance whose method was invoked | ||
| 148 | * @param method the method that was called | ||
| 149 | * @param args the arguments passed in the call. | ||
| 150 | * @return always null, if the method is a user-defined probe | ||
| 151 | */ | ||
| 152 | public Object invoke(Object proxy, Method method, Object[] args) { | ||
| 153 | if (method.getDeclaringClass() != providerType) { | ||
| 154 | try { | ||
| 155 | return method.invoke(this, args); | ||
| 156 | } catch (IllegalAccessException e) { | ||
| 157 | assert false; | ||
| 158 | } catch (InvocationTargetException e) { | ||
| 159 | assert false; | ||
| 160 | } | ||
| 161 | } else if (active) { | ||
| 162 | ProbeSkeleton p = probes.get(method); | ||
| 163 | if (p != null) { | ||
| 164 | // Skips argument check -- already done by javac | ||
| 165 | p.uncheckedTrigger(args); | ||
| 166 | } | ||
| 167 | } | ||
| 168 | return null; | ||
| 169 | } | ||
| 170 | |||
| 171 | /** | ||
| 172 | * Direct accessor for {@code Probe} objects. | ||
| 173 | * | ||
| 174 | * @param m the method corresponding to a probe | ||
| 175 | * @return the method associated probe object, or null | ||
| 176 | */ | ||
| 177 | public Probe getProbe(Method m) { | ||
| 178 | return active ? probes.get(m) : null; | ||
| 179 | } | ||
| 180 | |||
| 181 | /** | ||
| 182 | * Default provider disposal method. | ||
| 183 | * | ||
| 184 | * This is overridden in subclasses as needed. | ||
| 185 | */ | ||
| 186 | public void dispose() { | ||
| 187 | active = false; | ||
| 188 | probes.clear(); | ||
| 189 | } | ||
| 190 | |||
| 191 | /** | ||
| 192 | * Gets the user-specified provider name for the user's interface. | ||
| 193 | * | ||
| 194 | * If the user's interface has a {@ProviderName} annotation, that value | ||
| 195 | * is used. Otherwise we use the simple name of the user interface's class. | ||
| 196 | * @return the provider name | ||
| 197 | */ | ||
| 198 | protected String getProviderName() { | ||
| 199 | return getAnnotationString( | ||
| 200 | providerType, ProviderName.class, providerType.getSimpleName()); | ||
| 201 | } | ||
| 202 | |||
| 203 | /** | ||
| 204 | * Utility method for getting a string value from an annotation. | ||
| 205 | * | ||
| 206 | * Used for getting a string value from an annotation with a 'value' method. | ||
| 207 | * | ||
| 208 | * @param element the element that was annotated, either a class or method | ||
| 209 | * @param annotation the class of the annotation we're interested in | ||
| 210 | * @param defaultValue the value to return if the annotation doesn't | ||
| 211 | * exist, doesn't have a "value", or the value is empty. | ||
| 212 | */ | ||
| 213 | protected static String getAnnotationString( | ||
| 214 | AnnotatedElement element, Class<? extends Annotation> annotation, | ||
| 215 | String defaultValue) { | ||
| 216 | String ret = (String)getAnnotationValue( | ||
| 217 | element, annotation, "value", defaultValue); | ||
| 218 | return ret.isEmpty() ? defaultValue : ret; | ||
| 219 | } | ||
| 220 | |||
| 221 | /** | ||
| 222 | * Utility method for calling an arbitrary method in an annotation. | ||
| 223 | * | ||
| 224 | * @param element the element that was annotated, either a class or method | ||
| 225 | * @param annotation the class of the annotation we're interested in | ||
| 226 | * @param methodName the name of the method in the annotation we wish | ||
| 227 | * to call. | ||
| 228 | * @param defaultValue the value to return if the annotation doesn't | ||
| 229 | * exist, or we couldn't invoke the method for some reason. | ||
| 230 | * @return the result of calling the annotation method, or the default. | ||
| 231 | */ | ||
| 232 | protected static Object getAnnotationValue( | ||
| 233 | AnnotatedElement element, Class<? extends Annotation> annotation, | ||
| 234 | String methodName, Object defaultValue) { | ||
| 235 | Object ret = defaultValue; | ||
| 236 | try { | ||
| 237 | Method m = annotation.getMethod(methodName); | ||
| 238 | Annotation a = element.getAnnotation(annotation); | ||
| 239 | ret = m.invoke(a); | ||
| 240 | } catch (NoSuchMethodException e) { | ||
| 241 | assert false; | ||
| 242 | } catch (IllegalAccessException e) { | ||
| 243 | assert false; | ||
| 244 | } catch (InvocationTargetException e) { | ||
| 245 | assert false; | ||
| 246 | } catch (NullPointerException e) { | ||
| 247 | assert false; | ||
| 248 | } | ||
| 249 | return ret; | ||
| 250 | } | ||
| 251 | } | ||