History

My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/sun/tracing/ProviderSkeleton.java (1 of 18352 files). Show all

Unified · Split

java/pkg/sun/tracing/ProviderSkeleton.java+251−0
@@ -0,0 +1,251 @@
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+}