moved examples under doc per Erik

1 files changed, 123 insertions, 0 deletions

diff --git a/docs/dist/doc/examples/tracing/version2/Trace.java b/docs/dist/doc/examples/tracing/version2/Trace.java
new file mode 100644
index 000000000..cd631e278
--- /dev/null
+++ b/docs/dist/doc/examples/tracing/version2/Trace.java
@@ -0,0 +1,123 @@
+/*
+
+Copyright (c) Xerox Corporation 1998-2002.  All rights reserved.
+
+Use and copying of this software and preparation of derivative works based
+upon this software are permitted.  Any distribution of this software or
+derivative works must comply with all applicable United States export control
+laws.
+
+This software is made available AS IS, and Xerox Corporation makes no warranty
+about the software, its performance or its conformity to any specification.
+
+|<---            this code is formatted to fit into 80 columns             --->|
+|<---            this code is formatted to fit into 80 columns             --->|
+|<---            this code is formatted to fit into 80 columns             --->|
+
+*/
+
+package tracing.version2;
+
+import java.io.PrintStream;
+
+/**
+ *
+ * This class provides support for printing trace messages into a stream.
+ * Trace messages are printed before and after constructors and methods
+ * are executed.
+ * It defines one abstract crosscut for injecting that tracing functionality 
+ * into any application classes.
+ * To use it, provide a subclass that concretizes the abstract crosscut.
+ */
+abstract aspect Trace {
+
+    /*
+     * Functional part
+     */
+
+    /**
+     * There are 3 trace levels (values of TRACELEVEL):
+     * 0 - No messages are printed
+     * 1 - Trace messages are printed, but there is no indentation 
+     *     according to the call stack
+     * 2 - Trace messages are printed, and they are indented
+     *     according to the call stack
+     */
+    public static int TRACELEVEL = 2;
+    protected static PrintStream stream = System.err;
+    protected static int callDepth = 0;
+
+    /**
+     * Initialization.
+     */
+    public static void initStream(PrintStream s) {
+        stream = s;
+    }
+
+    protected static void traceEntry(String str) {
+        if (TRACELEVEL == 0) return;
+        if (TRACELEVEL == 2) callDepth++;
+        printEntering(str);
+    }
+
+    protected static void traceExit(String str) {
+        if (TRACELEVEL == 0) return;
+        printExiting(str);
+        if (TRACELEVEL == 2) callDepth--;
+    }
+
+    private static void printEntering(String str) {
+        printIndent();
+        stream.println("--> " + str);
+    }
+
+    private static void printExiting(String str) {
+        printIndent();
+        stream.println("<-- " + str);
+    }
+
+
+    private static void printIndent() {
+        for (int i = 0; i < callDepth; i++)
+            stream.print("  ");
+    }
+
+
+    /*
+     * Crosscut part
+     */
+
+    /**
+     * Application classes - left unspecified.
+     * Subclasses should concretize this pointcut with class names.
+     */
+    abstract pointcut myClass();
+    /**
+     * The constructors in those classes.
+     */
+    pointcut myConstructor(): myClass() && execution(new(..));
+    /**
+     * The methods of those classes.
+     */
+    pointcut myMethod(): myClass() && execution(* *(..));
+
+    /**
+     * Prints trace messages before and after executing constructors.
+     */
+    before(): myConstructor() {
+        traceEntry("" + thisJoinPointStaticPart.getSignature());
+    }
+    after(): myConstructor() {
+        traceExit("" + thisJoinPointStaticPart.getSignature());
+    }
+
+    /**
+     * Prints trace messages before and after executing methods.
+     */
+    before(): myMethod() {
+        traceEntry("" + thisJoinPointStaticPart.getSignature());
+    }
+    after(): myMethod() {
+        traceExit("" + thisJoinPointStaticPart.getSignature());
+    }
+}