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XLT (Xceptance LoadTest) is an extensive load and performance test tool developed and maintained by Xceptance.
/*
* Copyright (c) 2005-2022 Xceptance Software Technologies GmbH
*
* Licensed 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 com.xceptance.common.util;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import org.apache.commons.lang3.StringUtils;
import com.xceptance.common.lang.ThreadUtils;
/**
* The {@link ConsoleUiUtils} class provides utility methods to ease building console-based UIs.
*
* @author Jörg Werner (Xceptance Software Technologies GmbH)
*/
public final class ConsoleUiUtils
{
/**
* An {@link EofHandler} is called if EOF was detected while reading input from stdin.
*/
public interface EofHandler
{
/**
* Called if EOF was detected.
*/
public void onEof();
}
/**
* The list of registered {@link EofHandler} instances.
*/
private static final Set EOF_HANDLERS = new LinkedHashSet();
/**
* A reader on top of {@link System#in}.
*/
private static final BufferedReader STDIN_READER = new BufferedReader(new InputStreamReader(System.in));
/**
* Adds the passed {@link EofHandler} instance to the internal list of handlers.
*
* @param eofHandler
* the handler
*/
public static void addEofHandler(final EofHandler eofHandler)
{
ParameterCheckUtils.isNotNull(eofHandler, "eofHandler");
EOF_HANDLERS.add(eofHandler);
}
/**
* Asks the user for confirmation.
*
* @param message
* the message text presented to the user
* @return true if the user confirmed, false otherwise
*/
public static boolean confirm(String message)
{
message = message + " [y/n]";
while (true)
{
final String s = readLine(message);
if ("n".equalsIgnoreCase(s))
{
return false;
}
else if ("y".equalsIgnoreCase(s))
{
return true;
}
}
}
/**
* Presents the user a list of items from which the user might select one or more. The selected items will be
* returned. If so specified, an "All" item is added to the list, which - when chosen - selects all items at once.
*
* @param
* @param header
* the header text
* @param displayNames
* the display names of the items
* @param items
* the corresponding items
* @param allInsteadOfNone
* whether an "all" item is to be shown instead of the default "none" item
* @return the selected items (never null)
*/
public static List multiSelectItems(final String header, final List displayNames, final List items,
final boolean allInsteadOfNone)
{
return multiSelectItems(header, displayNames, items, allInsteadOfNone, null);
}
/**
* Presents the user a list of items from which the user might select one or more. The selected items will be
* returned. If so specified, an "All" item is added to the list, which - when chosen - selects all items at once.
*
* @param
* @param header
* the header text
* @param displayNames
* the display names of the items
* @param items
* the corresponding items
* @param allInsteadOfNone
* whether an "all" item is to be shown instead of the default "none" item
* @param allInsteadOfNothingLabel
* all/nothing label text. If blank there will be default labels.
* @return the selected items (never null)
*/
public static List multiSelectItems(final String header, List displayNames, final List items,
final boolean allInsteadOfNone, final String allInsteadOfNothingLabel)
{
// copy the list of display names as we will extend the list
displayNames = new ArrayList<>(displayNames);
// add the "all"/"none" item as the first item
if (StringUtils.isNotBlank(allInsteadOfNothingLabel))
{
displayNames.add(0, allInsteadOfNothingLabel);
}
else
{
displayNames.add(0, allInsteadOfNone ? "" : "");
}
// determine longest key
int maxKeyLength = String.valueOf(displayNames.size()).length();
// print the menu
System.out.println(header);
for (int i = 0; i < displayNames.size(); i++)
{
System.out.printf(" %s %s\n", StringUtils.leftPad("(" + i + ")", maxKeyLength + 2), displayNames.get(i));
}
// get the user's selection
while (true)
{
final String s = readLine();
if (StringUtils.isNotBlank(s))
{
try
{
final String[] parts = StringUtils.split(s, " ,;");
final Set result = new LinkedHashSet();
for (int i = 0; i < parts.length; i++)
{
final int n = Integer.parseInt(parts[i]);
if (n == 0)
{
// all/none item
if (allInsteadOfNone)
{
result.addAll(items);
break;
}
}
else
{
result.add(items.get(n - 1));
}
}
return new ArrayList(result);
}
catch (final IndexOutOfBoundsException e)
{
// simply retry
}
catch (final NumberFormatException e)
{
// simply retry
}
}
}
}
/**
* Asks the user to enter an integer value. The number must be greater than 0.
*
* @param message
* the message text
* @return the value entered
*/
public static int readInt(final String message)
{
while (true)
{
final String s = readLine(message);
try
{
final int i = Integer.parseInt(s);
if (i >= 1)
{
return i;
}
}
catch (final NumberFormatException e)
{
// simply retry
}
}
}
/**
* Reads a line of text from the console.
*
* @return the line just read (never null)
*/
public static String readLine()
{
return readLine(null);
}
/**
* Reads a line of text from the console.
*
* @param message
* the message text to show
* @return the line just read (never null)
*/
public static String readLine(final String message)
{
final StringBuilder prompt = new StringBuilder();
if (!StringUtils.isBlank(message))
{
prompt.append(message).append(' ');
}
prompt.append("=> ");
System.out.print(prompt);
try
{
final String s = STDIN_READER.readLine();
// EOF handling
if (s == null)
{
// give some visual feedback
System.out.println();
// execute any registered EOF handlers
runEofHandlers();
// block this thread until regular shutdown is complete
ThreadUtils.sleep();
}
return s;
}
catch (final IOException e)
{
throw new RuntimeException("Failed to read input from stdin", e);
}
}
/**
* Removes the passed {@link EofHandler} instance from the internal list of handlers.
*
* @param eofHandler
* the handler
*/
public static void removeEofHandler(final EofHandler eofHandler)
{
ParameterCheckUtils.isNotNull(eofHandler, "eofHandler");
EOF_HANDLERS.remove(eofHandler);
}
/**
* Asks the user to select an item from a list of items.
*
* @param
* @param header
* the header line
* @param keys
* the keys used to select the respective items (maybe null, in which case numbers will be
* used)
* @param displayNames
* the display names for the items
* @param items
* the list of items
* @return the selected item (never null)
*/
public static T selectItem(final String header, List keys, final List displayNames, final List items)
{
// build the list of keys if none was specified
if (keys == null)
{
keys = new ArrayList();
for (int i = 0; i < displayNames.size(); i++)
{
keys.add(String.valueOf(i + 1));
}
}
// parameter check
if (keys.size() != displayNames.size())
{
throw new IllegalArgumentException("The count of display names and keys has to be equal!");
}
if (keys.size() != items.size())
{
throw new IllegalArgumentException("The count of items and keys has to be equal!");
}
// determine longest key
int maxKeyLength = 0;
for (String key : keys)
{
maxKeyLength = Math.max(maxKeyLength, key.length());
}
// print the menu
System.out.println(header);
for (int i = 0; i < displayNames.size(); i++)
{
System.out.printf(" %s %s\n", StringUtils.leftPad("(" + keys.get(i) + ")", maxKeyLength + 2), displayNames.get(i));
}
// let the user choose an item
while (true)
{
// read the key
final String key = readLine();
// search the key in the list of keys and return the corresponding item
for (int i = 0; i < keys.size(); i++)
{
if (keys.get(i).equals(key))
{
return items.get(i);
}
}
}
}
/**
* Asks the user to select an item from a list of items.
*
* @param
* @param header
* the header line
* @param displayNames
* the display names for the items
* @param items
* the list of items
* @return the selected item (never null)
*/
public static T selectItem(final String header, final List displayNames, final List items)
{
// parameter check
if (displayNames.size() != items.size())
{
throw new IllegalArgumentException("The count of display names and items has to be equal!");
}
return selectItem(header, null, displayNames, items);
}
/**
* Checks whether the ENTER key was pressed.
*
* @return true if the ENTER key was pressed, false otherwise
*/
public static boolean wasEnterKeyPressed()
{
try
{
if (STDIN_READER.ready())
{
// consume a line of input
STDIN_READER.readLine();
return true;
}
else
{
// no input available
return false;
}
}
catch (final IOException e)
{
// should never happen
throw new RuntimeException("Failed to read input from stdin", e);
}
}
/**
* Runs the registered {@link EofHandler} instances in the order they were added.
*/
private static void runEofHandlers()
{
for (final EofHandler eofHandler : EOF_HANDLERS)
{
eofHandler.onEof();
}
}
/**
* Constructor. Declared private to avoid instantiation.
*/
private ConsoleUiUtils()
{
}
}