Github user sudheeshkatkam commented on a diff in the pull request:
https://github.com/apache/drill/pull/495#discussion_r63597486
--- Diff:
common/src/main/java/org/apache/drill/exec/util/SystemPropertyUtil.java ---
@@ -0,0 +1,189 @@
+/**
+ * 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.drill.exec.util;
+
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.regex.Pattern;
+
+/**
+ * A collection of utility methods to retrieve and parse the values of
Java system properties.
+ *
+ * This is a modified version of Netty's internal system property utility
class.
+ */
+public final class SystemPropertyUtil {
+ private static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(SystemPropertyUtil.class);
+
+ private static final Pattern INTEGER_PATTERN =
Pattern.compile("-?[0-9]+");
+
+ /**
+ * Returns {@code true} if and only if the system property with the
specified {@code key}
+ * exists.
+ */
+ public static boolean contains(String key) {
+ return get(key) != null;
+ }
+
+ /**
+ * Returns the value of the Java system property with the specified
+ * {@code key}, while falling back to {@code null} if the property
access fails.
+ *
+ * @return the property value or {@code null}
+ */
+ public static String get(String key) {
+ return get(key, null);
+ }
+
+ /**
+ * Returns the value of the Java system property with the specified
+ * {@code key}, while falling back to the specified default value if
+ * the property access fails.
+ *
+ * @return the property value.
+ * {@code def} if there's no such property or if an access to the
+ * specified property is not allowed.
+ */
+ public static String get(final String key, String def) {
+ if (key == null) {
+ throw new NullPointerException("key");
+ }
+ if (key.isEmpty()) {
+ throw new IllegalArgumentException("key must not be empty.");
+ }
+
+ String value = null;
+ try {
+ if (System.getSecurityManager() == null) {
+ value = System.getProperty(key);
+ } else {
+ value = AccessController.doPrivileged(new
PrivilegedAction<String>() {
+ @Override
+ public String run() {
+ return System.getProperty(key);
+ }
+ });
+ }
+ } catch (Exception e) {
+ logger.warn("Unable to retrieve a system property '" + key + "';
default values will be used.", e);
+ }
+
+ if (value == null) {
+ return def;
+ }
+
+ return value;
+ }
+
+ /**
+ * Returns the value of the Java system property with the specified
+ * {@code key}, while falling back to the specified default value if
+ * the property access fails.
+ *
+ * @return the property value.
+ * {@code def} if there's no such property or if an access to the
+ * specified property is not allowed.
+ */
+ public static boolean getBoolean(String key, boolean def) {
+ String value = get(key);
+ if (value == null) {
+ return def;
+ }
+
+ value = value.trim().toLowerCase();
+ if (value.isEmpty()) {
+ return true;
+ }
+
+ if ("true".equals(value) || "yes".equals(value) || "1".equals(value)) {
+ return true;
+ }
+
+ if ("false".equals(value) || "no".equals(value) || "0".equals(value)) {
+ return false;
+ }
+
+ logger.warn("Unable to parse the boolean system property '{}':{} -
using the default value: {}",
+ key, value, def);
+
+ return def;
+ }
+
+ /**
+ * Returns the value of the Java system property with the specified
+ * {@code key}, while falling back to the specified default value if
+ * the property access fails.
+ *
+ * @return the property value.
+ * {@code def} if there's no such property or if an access to the
+ * specified property is not allowed.
+ */
+ public static int getInt(String key, int def) {
+ String value = get(key);
+ if (value == null) {
+ return def;
+ }
+
+ value = value.trim().toLowerCase();
+ if (INTEGER_PATTERN.matcher(value).matches()) {
--- End diff --
I am not sure why the pattern matcher was in place. The difference I see is
"+1729" is allowed by `Integer.parseInt(...)` but not this matcher.
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