diff --git a/src/main/java/edu/caltech/nanodb/client/ExclusiveClient.java b/src/main/java/edu/caltech/nanodb/client/ExclusiveClient.java
index 5ec1918c231b82e8d4867b822a0258ed63b0ee40..afabd40c580fc1d889af6143c318fed7deb23f9d 100755
--- a/src/main/java/edu/caltech/nanodb/client/ExclusiveClient.java
+++ b/src/main/java/edu/caltech/nanodb/client/ExclusiveClient.java
@@ -53,19 +53,7 @@ public class ExclusiveClient extends InteractiveClient {
@Override
public CommandResult handleCommand(String command) {
- CommandResult result = server.doCommand(command, false);
-
- if (result.failed()) {
- Exception e = result.getFailure();
- if (e instanceof ParseCancellationException) {
- System.out.println("ERROR: Could not parse command");
- }
- else {
- System.out.println("ERROR: " + e.getMessage());
- }
- }
-
- return result;
+ return server.doCommand(command, false);
}
diff --git a/src/main/java/edu/caltech/nanodb/client/InteractiveClient.java b/src/main/java/edu/caltech/nanodb/client/InteractiveClient.java
index 032820edf0af663814234a3d8d1e393518670490..45c01492d4d1a79b927ab92b7d669d4792f93c64 100644
--- a/src/main/java/edu/caltech/nanodb/client/InteractiveClient.java
+++ b/src/main/java/edu/caltech/nanodb/client/InteractiveClient.java
@@ -2,12 +2,16 @@ package edu.caltech.nanodb.client;
import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
import java.io.InputStreamReader;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
import edu.caltech.nanodb.server.CommandResult;
+import org.antlr.v4.runtime.misc.ParseCancellationException;
/**
@@ -29,11 +33,25 @@ public abstract class InteractiveClient {
/** The buffer that accumulates each command's text. */
private StringBuilder enteredText;
+ /** A flag that records if we are exiting the interactive client. */
+ private boolean exiting;
+
+ /**
+ * Start up the interactive client. The specific way the client
+ * interacts with the server dictates how this startup mechanism
+ * will work.
+ *
+ * @throws Exception if any error occurs during startup
+ */
public abstract void startup() throws Exception;
- public void mainloop() {
+ /**
+ * This is the interactive mainloop that handles input from the standard
+ * input stream of the program.
+ */
+ protected void mainloop() {
// We don't use the console directly, since we can't read/write it
// if someone redirects a file onto the client's input-stream.
boolean hasConsole = (System.console() != null);
@@ -43,13 +61,13 @@ public abstract class InteractiveClient {
"Welcome to NanoDB. Exit with EXIT or QUIT command.\n");
}
- boolean exiting = false;
- BufferedReader bufReader = new BufferedReader(new InputStreamReader(System.in));
+ exiting = false;
+ BufferedReader bufReader =
+ new BufferedReader(new InputStreamReader(System.in));
while (!exiting) {
enteredText = new StringBuilder();
boolean firstLine = true;
-getcmd:
while (true) {
try {
if (hasConsole) {
@@ -73,21 +91,9 @@ getcmd:
enteredText.append(line).append('\n');
- // Process any commands in the entered text.
- while (true) {
- String command = getCommandString();
- if (command == null)
- break; // No more complete commands.
-
- // if (logger.isDebugEnabled())
- // logger.debug("Command string:\n" + command);
-
- CommandResult result = handleCommand(command);
- if (result.isExit()) {
- exiting = true;
- break getcmd;
- }
- }
+ processEnteredText();
+ if (exiting)
+ break;
if (enteredText.length() == 0)
firstLine = true;
@@ -102,6 +108,111 @@ getcmd:
}
+ /**
+ * This helper function processes the contents of the {@link #enteredText}
+ * field, consuming comments, handling client "shell commands" and
+ * regular commands that are handled by the
+ * {@link edu.caltech.nanodb.server.NanoDBServer}. Whatever command or
+ * comment is processed will also be removed from the {@code enteredText}
+ * buffer by this function. Note also that multiple commands will be
+ * processed, if present.
+ */
+ private void processEnteredText() {
+ // Process any commands in the entered text.
+ while (true) {
+ // Consume leading whitespace
+ while (enteredText.length() > 0 &&
+ Character.isWhitespace(enteredText.charAt(0))) {
+ enteredText.deleteCharAt(0);
+ }
+
+ // Consume comments
+ if (enteredText.length() >= 2) {
+ if ("--".equals(enteredText.substring(0, 2))) {
+ // Consume single-line comment
+ int endIdx = 2;
+
+ // Look for the end of the line.
+ while (endIdx < enteredText.length() &&
+ enteredText.charAt(endIdx) != '\n') {
+ endIdx++;
+ }
+
+ if (endIdx == enteredText.length()) {
+ // Didn't find newline character. Can't consume this
+ // comment yet.
+ return;
+ }
+
+ endIdx++; // Skip the newline character as well.
+ enteredText.delete(0, endIdx);
+
+ // Go back and try to find more commands.
+ continue;
+ }
+ else if ("/*".equals(enteredText.substring(0, 2))) {
+ // Consume block comment
+
+ int endIdx = 2;
+
+ // Look for the end of the block comment.
+ while (endIdx + 1 < enteredText.length() &&
+ (enteredText.charAt(endIdx) != '*' ||
+ enteredText.charAt(endIdx + 1) != '/')) {
+ endIdx++;
+ }
+
+ if (endIdx + 1 == enteredText.length()) {
+ // Didn't find end of block comment. Can't consume
+ // this comment yet.
+ return;
+ }
+
+ endIdx += 2; // Skip the end of the block-comment.
+ enteredText.delete(0, endIdx);
+
+ // Go back and try to find more commands.
+ continue;
+ }
+ }
+
+ // Look for shell commands
+ if (enteredText.length() > 0 && enteredText.charAt(0) == '\\') {
+ // This is a shell command, which continues to the
+ // end of the current line.
+ int endIdx = 0;
+ while (endIdx < enteredText.length() &&
+ enteredText.charAt(endIdx) != '\n') {
+ endIdx++;
+ }
+ endIdx++; // Include the newline character too
+
+ String shellCommand = enteredText.substring(0, endIdx);
+ enteredText.delete(0, endIdx);
+
+ handleShellCommand(shellCommand);
+ continue;
+ }
+
+ String command = getCommandString();
+ if (command == null)
+ break; // Couldn't find a complete command.
+
+ // if (logger.isDebugEnabled())
+ // logger.debug("Command string:\n" + command);
+
+ CommandResult result = handleCommand(command);
+ if (result.isExit()) {
+ exiting = true;
+ break;
+ }
+ else {
+ outputCommandResult(result);
+ }
+ }
+ }
+
+
/**
* This helper method goes through the {@link #enteredText} buffer, trying
* to identify the extent of the next command string. This is done using
@@ -165,6 +276,99 @@ getcmd:
public abstract CommandResult handleCommand(String command);
+ /**
+ * Handle "shell commands," which are commands that the client itself
+ * handles on behalf of the user. Shell commands start with a backslash
+ * "\" character.
+ *
+ * @param shellCommand the command to handle.
+ */
+ private void handleShellCommand(String shellCommand) {
+ // Split the shell command into parts
+ String[] parts = shellCommand.split("\\s+", 2);
+ parts[0] = parts[0].toLowerCase();
+
+ if ("\\source".equals(parts[0])) {
+ // Source the requested SQL file.
+
+ StringBuilder oldText = enteredText;
+ enteredText = new StringBuilder();
+ String filename = parts[1].strip();
+
+ // Open the file with a try-with-resources so it will always be
+ // closed when we are done with the file.
+ try (BufferedReader reader =
+ new BufferedReader(new FileReader(filename))) {
+
+ while (true) {
+ String line = reader.readLine();
+ if (line == null)
+ break;
+
+ // Inject the line of the file into the buffer.
+ enteredText.append(line).append('\n');
+
+ // Attempt to process any operations in the entered text.
+ // If there are no complete commands, this will be a
+ // no-op. If there are multiple complete commands, they
+ // will all be processed.
+ processEnteredText();
+ }
+ }
+ catch (FileNotFoundException e) {
+ System.out.println("ERROR: Could not open file \"" +
+ filename + "\"");
+ }
+ catch (IOException e) {
+ System.out.println("ERROR: Could not read file \"" +
+ filename + "\": " + e.getMessage());
+ }
+
+ enteredText = oldText;
+ }
+ else if ("\\help".equals(parts[0])) {
+ // Show help information.
+ System.out.println("You can enter any NanoDB SQL command, or " +
+ "the following built-in commands.");
+ System.out.println("EXIT; or QUIT; will exit the NanoDB client.");
+ System.out.println();
+ System.out.println("\\help");
+ System.out.println("\tDisplays this help information.");
+ System.out.println();
+ System.out.println("\\source filename.sql");
+ System.out.println("\tLoads and executes the contents of \"filename.sql\".");
+ System.out.println();
+ }
+ else {
+ System.out.println("ERROR: Unrecognized shell command \"" +
+ parts[0] + "\"");
+ }
+
+ }
+
+
+ /**
+ * Outputs relevant information from the command-result object.
+ *
+ * @param result the command-result object to output
+ */
+ private void outputCommandResult(CommandResult result) {
+ // TODO: Right now we only print out error information. In the
+ // future we will want to output other details. This
+ // functionality also needs to be integrated with the tuple-
+ // output code from the server. Need to think about this more.
+ if (result.failed()) {
+ Exception e = result.getFailure();
+ if (e instanceof ParseCancellationException) {
+ System.out.println("ERROR: Could not parse command");
+ }
+ else {
+ System.out.println("ERROR: " + e.getMessage());
+ }
+ }
+ }
+
+
/**
* Shut down the interactive client. The specific way the client
* interacts with the server dictates how this shutdown mechanism