Move ExceptionWithContext to Util module

util/src/main/java/org/jf/util/ExceptionWithContext.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * As per the Apache license requirements, this file has been modified
+ * from its original state.
+ *
+ * Such modifications are Copyright (C) 2010 Ben Gruver, and are released
+ * under the original license
+ */
+
+package org.jf.util;
+
+import java.io.PrintStream;
+import java.io.PrintWriter;
+
+/**
+ * Exception which carries around structured context.
+ */
+public class ExceptionWithContext
+        extends RuntimeException {
+    /** non-null; human-oriented context of the exception */
+    private StringBuffer context;
+
+    /**
+     * Augments the given exception with the given context, and return the
+     * result. The result is either the given exception if it was an
+     * {@link ExceptionWithContext}, or a newly-constructed exception if it
+     * was not.
+     *
+     * @param ex non-null; the exception to augment
+     * @param str non-null; context to add
+     * @return non-null; an appropriate instance
+     */
+    public static ExceptionWithContext withContext(Throwable ex, String str) {
+        ExceptionWithContext ewc;
+
+        if (ex instanceof ExceptionWithContext) {
+            ewc = (ExceptionWithContext) ex;
+        } else {
+            ewc = new ExceptionWithContext(ex);
+        }
+
+        ewc.addContext(str);
+        return ewc;
+    }
+
+    /**
+     * Constructs an instance.
+     *
+     * @param message human-oriented message
+     */
+    public ExceptionWithContext(String message) {
+        this(message, null);
+    }
+
+    /**
+     * Constructs an instance.
+     *
+     * @param cause null-ok; exception that caused this one
+     */
+    public ExceptionWithContext(Throwable cause) {
+        this(null, cause);
+    }
+
+    /**
+     * Constructs an instance.
+     *
+     * @param message human-oriented message
+     * @param cause null-ok; exception that caused this one
+     */
+    public ExceptionWithContext(String message, Throwable cause) {
+        super((message != null) ? message :
+              (cause != null) ? cause.getMessage() : null,
+              cause);
+
+        if (cause instanceof ExceptionWithContext) {
+            String ctx = ((ExceptionWithContext) cause).context.toString();
+            context = new StringBuffer(ctx.length() + 200);
+            context.append(ctx);
+        } else {
+            context = new StringBuffer(200);
+        }
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void printStackTrace(PrintStream out) {
+        super.printStackTrace(out);
+        out.println(context);
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public void printStackTrace(PrintWriter out) {
+        super.printStackTrace(out);
+        out.println(context);
+    }
+
+    /**
+     * Adds a line of context to this instance.
+     *
+     * @param str non-null; new context
+     */
+    public void addContext(String str) {
+        if (str == null) {
+            throw new NullPointerException("str == null");
+        }
+
+        context.append(str);
+        if (!str.endsWith("\n")) {
+            context.append('\n');
+        }
+    }
+
+    /**
+     * Gets the context.
+     *
+     * @return non-null; the context
+     */
+    public String getContext() {
+        return context.toString();
+    }
+
+    /**
+     * Prints the message and context.
+     *
+     * @param out non-null; where to print to
+     */
+    public void printContext(PrintStream out) {
+        out.println(getMessage());
+        out.print(context);
+    }
+
+    /**
+     * Prints the message and context.
+     *
+     * @param out non-null; where to print to
+     */
+    public void printContext(PrintWriter out) {
+        out.println(getMessage());
+        out.print(context);
+    }
+}