Merge pull request #14 from BorderTech/touchfile

Touchfile

Author: jonathanaustin

pom.xml

@@ -10,7 +10,7 @@
 	<parent>
 		<groupId>com.github.bordertech.common</groupId>
 		<artifactId>qa-parent</artifactId>
-		<version>1.0.9</version>
+		<version>1.0.10</version>
 	</parent>
 
 	<packaging>jar</packaging>
@@ -64,4 +64,5 @@
 		</dependency>
 	</dependencies>
 
+
 </project>

spotbugs-exclude-filter.xml

@@ -3,7 +3,6 @@
 
 	<!-- False Positive on Loading Property Filenames -->
 	<Match>
-		<Class name="com.github.bordertech.config.DefaultConfiguration"/>
 		<Bug pattern="PATH_TRAVERSAL_IN" />
 	</Match>
 

src/main/java/com/github/bordertech/config/Config.java

@@ -11,6 +11,7 @@
 import org.apache.commons.configuration.CompositeConfiguration;
 import org.apache.commons.configuration.Configuration;
 import org.apache.commons.configuration.MapConfiguration;
+import org.apache.commons.lang.StringUtils;
 
 /**
  * The Config class is the central access point to the configuration mechanism, and is used to read or modify the
@@ -34,22 +35,46 @@
  * <li><code>bordertech-local.properties</code> - local developer properties</li>
  * </ul>
  *
+ * <p>
+ * A touchfile can be set via the parameter <code>bordertech.config.touchfile</code>. The touchfile is checked when
+ * {@link #getInstance()} is called. To avoid excessive IO an interval (in milli seconds) between checks can be set via
+ * <code>bordertech.config.touchfile.interval</code> and defaults to <code>10000</code>.
+ * </p>
+ *
  * @author Joshua Barclay
  * @author Jonathan Austin
  * @since 1.0.0
+ *
+ * @see DefaultConfiguration
+ * @see InitHelper
+ * @see ConfigurationLoader
  */
 public final class Config {
 
 	/**
-	 * The current configuration.
+	 * Used to lock the config.
 	 */
-	private static Configuration configuration = loadConfiguration();
+	private static final Object LOCK = new Object();
 
 	/**
 	 * Contains the complete set of property change listeners that have registered with this class.
 	 */
 	private static final Set<PropertyChangeListener> PROPERTY_CHANGE_LISTENERS = new HashSet<>();
 
+	/**
+	 * The current configuration.
+	 */
+	private static Configuration configuration;
+
+	/**
+	 * Touchfile (if configured).
+	 */
+	private static Touchfile touchfile;
+
+	static {
+		loadConfiguration();
+	}
+
 	/**
 	 * Prevent instantiation of this utility class.
 	 */
@@ -60,16 +85,41 @@ private Config() {
 	 * @return the current configuration.
 	 */
 	public static Configuration getInstance() {
+		// If a touchfile has been set, check if it has changed and reload if necessary
+		if (touchfile != null) {
+			synchronized (LOCK) {
+				if (touchfile.hasChanged()) {
+					loadConfiguration();
+				}
+			}
+		}
 		return configuration;
 	}
 
 	/**
 	 * Resets the configuration back to the default internal configuration. All configuration changes which have been
 	 * made will be lost. This method is primarily intended for unit testing.
 	 */
-	public static synchronized void reset() {
-		configuration = loadConfiguration();
-		notifyListeners();
+	public static void reset() {
+		synchronized (LOCK) {
+			loadConfiguration();
+		}
+	}
+
+	/**
+	 * <p>
+	 * Sets the current configuration.</p>
+	 * <p>
+	 * <b>Warning: </b> this will ignore any defined ConfigurationLoaders</p>
+	 *
+	 * @param configuration the configuration to set.
+	 */
+	public static void setConfiguration(final Configuration configuration) {
+		synchronized (LOCK) {
+			Config.configuration = configuration;
+			configTouchfile();
+			notifyListeners();
+		}
 	}
 
 	/**
@@ -79,7 +129,7 @@ public static synchronized void reset() {
 	 * @return a copy of the given configuration.
 	 */
 	public static Configuration copyConfiguration(final Configuration original) {
-		Configuration copy = new MapConfiguration(new HashMap<String, Object>());
+		Configuration copy = new MapConfiguration(new HashMap<>());
 
 		for (Iterator<?> i = original.getKeys(); i.hasNext();) {
 			String key = (String) i.next();
@@ -91,23 +141,9 @@ public static Configuration copyConfiguration(final Configuration original) {
 
 			copy.setProperty(key, value);
 		}
-
 		return copy;
 	}
 
-	/**
-	 * <p>
-	 * Sets the current configuration.</p>
-	 * <p>
-	 * <b>Warning: </b> this will ignore any defined ConfigurationLoaders</p>
-	 *
-	 * @param configuration the configuration to set.
-	 */
-	public static synchronized void setConfiguration(final Configuration configuration) {
-		Config.configuration = configuration;
-		notifyListeners();
-	}
-
 	/**
 	 * This method notifies all the {@link PropertyChangeListener}s that have registered with this object that a change
 	 * has occurred.
@@ -147,11 +183,42 @@ public static void addPropertyChangeListener(final PropertyChangeListener listen
 	}
 
 	/**
-	 * @return the configuration to use.
+	 * Load the configuration.
 	 */
-	private static synchronized Configuration loadConfiguration() {
+	private static void loadConfiguration() {
 		Configuration config = checkSLIConfiguration();
-		return config == null ? getDefaultConfiguration() : config;
+		if (config == null) {
+			config = getDefaultConfiguration();
+		}
+		Config.configuration = config;
+		configTouchfile();
+		notifyListeners();
+	}
+
+	/**
+	 * Configure the touchfile (if provided).
+	 */
+	private static void configTouchfile() {
+		String file = getTouchFileName();
+		if (StringUtils.isEmpty(file)) {
+			touchfile = null;
+		} else {
+			touchfile = new Touchfile(file, getTouchFileInterval());
+		}
+	}
+
+	/**
+	 * @return the touch file name
+	 */
+	private static String getTouchFileName() {
+		return configuration.getString("bordertech.config.touchfile");
+	}
+
+	/**
+	 * @return the touch file interval (in milli seconds)
+	 */
+	private static long getTouchFileInterval() {
+		return configuration.getLong("bordertech.config.touchfile.interval", 10000);
 	}
 
 	/**
@@ -170,7 +237,7 @@ private static Configuration checkSLIConfiguration() {
 
 		// Use a CompositeConfiguration if there are custom ConfigurationLoader implementations.
 		if (iterator.hasNext()) {
-			CompositeConfiguration compositeConfig = new CompositeConfiguration(new MapConfiguration(new HashMap<String, Object>()));
+			CompositeConfiguration compositeConfig = new CompositeConfiguration(new MapConfiguration(new HashMap<>()));
 			while (iterator.hasNext()) {
 				compositeConfig.addConfiguration(iterator.next().getConfiguration());
 			}

src/main/java/com/github/bordertech/config/DefaultConfiguration.java

@@ -39,6 +39,8 @@
  *
  * @author Jonathan Austin
  * @since 1.0.0
+ *
+ * @see Config
  */
 public class DefaultConfiguration implements Configuration {
 
@@ -316,7 +318,7 @@ private String getDebuggingInfo() {
 				codesourceStr = codesource == null ? "" : " code location of ConfigImpl: " + codesource.getLocation();
 			}
 		} catch (Exception failed) {
-			codesourceStr = "Could not determine location of ConfigImpl.";
+			codesourceStr = "Could not determine location of ConfigImpl [" + failed.getMessage() + "].";
 		}
 
 		StringBuilder info = new StringBuilder();
@@ -325,8 +327,7 @@ private String getDebuggingInfo() {
 		info.append(codesourceStr);
 		info.append("\nWorking directory is ");
 		info.append(workingDir);
-		info.append(
-				"\nParameters have loaded, there is a full parameter dump in log4j FILE appender at ");
+		info.append("\nParameters have loaded, there is a full parameter dump in log4j FILE appender at ");
 		info.append(get(paramsFile));
 		info.append("\nTo dump all params to stdout set ");
 		info.append(DUMP);

src/main/java/com/github/bordertech/config/InitHelper.java

@@ -29,6 +29,8 @@
  *
  * @author Jonathan Austin
  * @since 1.0.0
+ *
+ * @see Config
  */
 public final class InitHelper {
 

src/main/java/com/github/bordertech/config/Touchfile.java

@@ -0,0 +1,103 @@
+package com.github.bordertech.config;
+
+import java.io.File;
+
+/**
+ * Monitor a touchfile to check if it has changed.
+ */
+public class Touchfile {
+
+	/**
+	 * Touchfile name.
+	 */
+	private final String filename;
+
+	/**
+	 * The touch file.
+	 */
+	private final File touchfile;
+
+	/**
+	 * Check interval in milli seconds.
+	 */
+	private final long checkInterval;
+
+	/**
+	 * The last time the file was checked.
+	 */
+	private long lastChecked;
+
+	/**
+	 * The files last modified time.
+	 */
+	private long lastModified;
+
+	/**
+	 * @param filename the touch file name
+	 * @param checkInterval the interval to check the file in milli seconds
+	 */
+	public Touchfile(final String filename, final long checkInterval) {
+		if (filename == null || filename.isEmpty()) {
+			throw new IllegalArgumentException("A touch filename must be provided.");
+		}
+		this.filename = filename;
+		this.touchfile = new File(filename);
+		this.checkInterval = checkInterval < 0 ? 0 : checkInterval;
+		this.lastChecked = System.currentTimeMillis();
+		this.lastModified = touchfile.lastModified();
+	}
+
+	/**
+	 *
+	 * @return true if touch file has changed
+	 */
+	public boolean hasChanged() {
+
+		// Has the check interval passed?
+		long now = System.currentTimeMillis();
+		if (now - lastChecked < checkInterval) {
+			return false;
+		}
+		lastChecked = now;
+
+		// Has the file changed?
+		long modified = touchfile.lastModified();
+		if (lastModified == modified) {
+			// No Change
+			return false;
+		}
+
+		// Has changed so save new file details
+		lastModified = modified;
+		return true;
+	}
+
+	/**
+	 * @return the file name
+	 */
+	public final String getFilename() {
+		return filename;
+	}
+
+	/**
+	 * @return the check interval
+	 */
+	public final long getCheckInterval() {
+		return checkInterval;
+	}
+
+	/**
+	 * @return the last checked time
+	 */
+	public final long getLastChecked() {
+		return lastChecked;
+	}
+
+	/**
+	 * @return the file last modified
+	 */
+	public final long getLastModified() {
+		return lastModified;
+	}
+
+}

src/test/java/com/github/bordertech/config/ConfigTest.java

@@ -6,29 +6,27 @@
 
 /**
  * Ensure the Config class does what it says.
+ *
  * @author Rick Brown
  */
 public class ConfigTest {
 
 	@Test
 	public void testGetInstance() {
-		System.out.println("getInstance");
 		Configuration expResult = Config.getInstance();
 		Configuration result = Config.getInstance();
 		Assert.assertSame("The singleton should return the same instance", expResult, result);
 	}
 
 	@Test
 	public void testCopyConfiguration() {
-		System.out.println("copyConfiguration");
 		Configuration config = Config.getInstance();
 		Configuration result = Config.copyConfiguration(config);
 		Assert.assertNotSame("Copy should return a new instance", config, result);
 	}
 
 	@Test
 	public void testCopyConfigurationWithProps() {
-		System.out.println("copyConfiguration");
 		Configuration config = Config.getInstance();
 		final String expected = "kungfu";
 		config.setProperty("kung.fu", expected);