limit history commands size

pom.xml

@@ -50,11 +50,10 @@
 			<artifactId>log4j</artifactId>
 			<version>1.2.14</version>
 		</dependency>
-		<!-- consider removing dependency on commons-io -->
 		<dependency>
 			<groupId>commons-io</groupId>
 			<artifactId>commons-io</artifactId>
-			<version>1.4</version>
+			<version>2.3</version>
 		</dependency>
 
 		<!-- External modules -->

src/main/java/org/springframework/shell/JLineShell.java

@@ -27,6 +27,7 @@ import jline.ANSIBuffer.ANSICodes;
 import jline.ConsoleReader;
 import jline.WindowsTerminal;
 
+import org.apache.commons.io.input.ReversedLinesFileReader;
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactoryUtils;
 import org.springframework.context.ApplicationContext;
@@ -40,7 +41,6 @@ import org.springframework.roo.shell.event.ShellStatus.Status;
 import org.springframework.roo.shell.event.ShellStatusListener;
 import org.springframework.roo.support.util.Assert;
 import org.springframework.roo.support.util.ClassUtils;
-import org.springframework.roo.support.util.FileCopyUtils;
 import org.springframework.roo.support.util.IOUtils;
 import org.springframework.roo.support.util.OsUtils;
 import org.springframework.roo.support.util.StringUtils;
@@ -63,8 +63,7 @@ import org.springframework.shell.plugin.PromptProvider;
  * @author Jarred Li
  * @since 1.0
  */
-public abstract class JLineShell extends AbstractShell 
+public abstract class JLineShell extends AbstractShell implements CommandMarker, Shell, Runnable {
-				implements CommandMarker, Shell, Runnable {
 
 	// Constants
 	private static final String ANSI_CONSOLE_CLASSNAME = "org.fusesource.jansi.AnsiConsole";
@@ -134,21 +133,10 @@ public abstract class JLineShell extends AbstractShell
 		openFileLogIfPossible();
 
 		// Try to build previous command history from the project's log
-		try {
+
-			String logFileContents = FileCopyUtils.copyToString(new File(this.historyFileName));
+		String[] filteredLogEntries = filterLogEntry();
-			String[] logEntries = logFileContents.split(StringUtils.LINE_SEPARATOR);
+		for (String logEntry : filteredLogEntries) {
-			// LIFO
+			reader.getHistory().addToHistory(logEntry);
-			int size = 0;
-			for (String logEntry : logEntries) {
-				if (!logEntry.startsWith("//")) {
-					reader.getHistory().addToHistory(logEntry);
-					size++;
-					if(size > historySize){
-						break;
-					}
-				}
-			}
-		} catch (IOException ignored) {
 		}
 
 		flashMessageRenderer();
@@ -190,8 +178,37 @@ public abstract class JLineShell extends AbstractShell
 
 	}
 
-	public void printBannerAndWelcome(){
+	/**
-		if(printBanner){
+	 * read history commands from history log. the history size if determined by --histsize options. 
+	 * 
+	 * @return history commands
+	 */
+	private String[] filterLogEntry() {
+		ArrayList<String> entries = new ArrayList<String>();		
+		try {
+			ReversedLinesFileReader reader = new ReversedLinesFileReader(new File(this.historyFileName));
+			int size = 0;
+			String line = null;
+			while ((line = reader.readLine()) != null) {
+				if (!line.startsWith("//")) {
+					size++;
+					if (size > historySize) {
+						break;
+					}
+					else {
+						entries.add(line);
+					}
+				}
+			}
+		} catch (IOException e) {
+			logger.warning("read history file failed");
+		}
+		Collections.reverse(entries);
+		return entries.toArray(new String[0]);
+	}
+
+	public void printBannerAndWelcome() {
+		if (printBanner) {
 			logger.info(this.version);
 			logger.info(getWelcomeMessage());
 		}
@@ -546,7 +563,7 @@ public abstract class JLineShell extends AbstractShell
 		this.applicatonContext = applicationContext;
 	}
 
-	public void costomizePlugin(){
+	public void costomizePlugin() {
 		this.historyFileName = getHistoryFileName();
 		this.promptText = getPromptText();
 		this.version = getBannerText()[0];
@@ -569,7 +586,7 @@ public abstract class JLineShell extends AbstractShell
 	 * 
 	 * @return prompt text
 	 */
-	private String getPromptText(){
+	private String getPromptText() {
 		return getHighestPriorityProvider(PromptProvider.class).getPromptText();
 	}
 
@@ -579,7 +596,7 @@ public abstract class JLineShell extends AbstractShell
 	 * @return BannerText[0]: Banner
 	 *         BannerText[1]: Welcome Message.
 	 */
-	private String[] getBannerText(){
+	private String[] getBannerText() {
 		String[] bannerText = new String[2];
 		BannerProvider provider = getHighestPriorityProvider(BannerProvider.class);
 		bannerText[0] = provider.getBanner();
@@ -588,9 +605,8 @@ public abstract class JLineShell extends AbstractShell
 	}
 
 
-	private <T extends PluginProvider> T getHighestPriorityProvider(Class<T> t){
+	private <T extends PluginProvider> T getHighestPriorityProvider(Class<T> t) {
-		Map<String, T> providers = BeanFactoryUtils.beansOfTypeIncludingAncestors(
+		Map<String, T> providers = BeanFactoryUtils.beansOfTypeIncludingAncestors(this.applicatonContext, t);
-				this.applicatonContext, t);
 		List<T> sortedProviders = new ArrayList<T>(providers.values());
 		Collections.sort(sortedProviders, annocationOrderComparator);
 		T highestPriorityProvider = sortedProviders.get(0);
@@ -602,7 +618,7 @@ public abstract class JLineShell extends AbstractShell
 	 * 
 	 */
 	@Override
-	public String version(String text){
+	public String version(String text) {
 		return this.version;
 	}
 
@@ -611,7 +627,7 @@ public abstract class JLineShell extends AbstractShell
 	 * 
 	 * @return welcome message
 	 */
-	public String getWelcomeMessage(){
+	public String getWelcomeMessage() {
 		return this.welcomeMessage;
 	}