svn commit: r1884972 - /pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java

[rw...@apache.org]

Author: rwhitcomb
Date: Wed Dec 30 23:28:13 2020
New Revision: 1884972

URL: http://svn.apache.org/viewvc?rev=1884972&view=rev
Log:
Add ExceptionUtils class to help with formatting exception messages.

Added:
    pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java

Added: pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java
URL: http://svn.apache.org/viewvc/pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java?rev=1884972&view=auto
==============================================================================
--- pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java (added)
+++ pivot/trunk/core/src/org/apache/pivot/util/ExceptionUtils.java Wed Dec 30 23:28:13 2020
@@ -0,0 +1,133 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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.
+ */
+package org.apache.pivot.util;
+
+import java.io.FileNotFoundException;
+import java.net.UnknownHostException;
+import java.nio.charset.CharacterCodingException;
+import java.nio.file.NoSuchFileException;
+
+
+/**
+ * Utility class that has various methods to help with exception handling
+ * and display.
+ */
+public final class ExceptionUtils {
+    /** Private constructor since this is a utility class. */
+    private ExceptionUtils() {
+    }
+
+    /**
+     * Standalone function to produce a reasonable string of the given
+     * exception, including the message and cause (all the way up to
+     * the original exception thrown).
+     *
+     * @param ex  Any old exception we want to report on.
+     * @return    A string representation of the error.
+     */
+    public static String toString(final Throwable ex) {
+        StringBuilder buf = new StringBuilder();
+        toString(ex, buf);
+        return buf.toString();
+    }
+
+    /**
+     * Standalone version to do a "pure" string (using spaces instead of newlines).
+     *
+     * @param ex        The exception to report.
+     * @param useSpaces Whether to use spaces instead of newlines to separate
+     *                  the chain of causal exceptions.
+     * @return          String representation of the exception.
+     */
+    public static String toString(final Throwable ex, final boolean useSpaces) {
+        StringBuilder buf = new StringBuilder();
+        toString(ex, buf, false, useSpaces, false);
+        return buf.toString();
+    }
+
+    /**
+     * Incremental version which allows for prepended or appended
+     * content by being passed the buffer in which to work.
+     *
+     * @param    ex    The exception to report.
+     * @param    buf   The buffer used to build the content.
+     */
+    public static void toString(final Throwable ex, final StringBuilder buf) {
+        toString(ex, buf, false, false, false);
+    }
+
+    /**
+     * Incremental version with more options.
+     *
+     * @param    ex          The exception to report.
+     * @param    buf         The buffer to build the string representation in.
+     * @param    useToString <tt>true</tt> to format using the {@link Throwable#toString}
+     *                       method instead of the {@link Throwable#getMessage} for the text.
+     * @param    useSpaces   <tt>true</tt> to use spaces instead of newlines to separate
+     *                       the chained exceptions.
+     * @param    convertTabs Convert any tab characters to single spaces (for use in controls
+     *                       that don't deal with tabs correctly; some do).
+     */
+    public static void toString(
+        final Throwable ex,
+        final StringBuilder buf,
+        final boolean useToString,
+        final boolean useSpaces,
+        final boolean convertTabs) {
+
+        for (Throwable next = ex; next != null;) {
+            String msg, className;
+
+            if (useToString) {
+                msg = next.toString();
+            } else {
+                msg       = next.getLocalizedMessage();
+                className = next.getClass().getSimpleName();
+
+                if (msg == null) {
+                    msg = className;
+                } else if ((next instanceof UnknownHostException)
+                        || (next instanceof NoClassDefFoundError)
+                        || (next instanceof ClassNotFoundException)
+                        || (next instanceof NullPointerException)
+                        || (next instanceof CharacterCodingException)
+                        || (next instanceof FileNotFoundException)
+                        || (next instanceof NoSuchFileException)
+                        || (next instanceof UnsupportedOperationException)
+                        || (next instanceof NumberFormatException)) {
+                    msg = String.format("%1$s: %2$s", className, msg);
+                }
+            }
+            buf.append(msg);
+
+            next = next.getCause();
+
+            if (next != null) {
+                buf.append(useSpaces ? ' ' : '\n');
+            }
+        }
+
+        if (convertTabs) {
+            int ix = 0;
+            while ((ix = buf.indexOf("\t", ix)) >= 0) {
+                buf.setCharAt(ix++, ' ');
+            }
+        }
+    }
+
+}
+