Package org.jline.reader.impl.history

Class DefaultHistory

java.lang.Object

org.jline.reader.impl.history.DefaultHistory

All Implemented Interfaces:

Iterable<History.Entry>, History

public class DefaultHistory
extends Object
implements History

Default implementation of History with file-based persistent storage.

This class provides a complete implementation of the History interface with the following features:

• In-memory storage of history entries with configurable size limits
• Persistent storage in a text file with configurable location and size limits
• Support for timestamped history entries
• Filtering of entries based on patterns defined in the LineReader.HISTORY_IGNORE variable
• Options to ignore duplicates, reduce blanks, and ignore commands starting with spaces
• Incremental saving of history entries
• History navigation (previous/next, first/last, etc.)

The history file format is either plain text with one command per line, or if LineReader.Option.HISTORY_TIMESTAMPED is set, each line starts with a timestamp in milliseconds since epoch, followed by a colon and the command text.

Applications using this class should install a shutdown hook to call save() to ensure history is saved to disk when the application exits.

Example usage:

 LineReader reader = LineReaderBuilder.builder()
     .variable(LineReader.HISTORY_FILE, Paths.get(System.getProperty("user.home"), ".myapp_history"))
     .build();
 // History is automatically attached to the reader

 // To save history manually:
 ((DefaultHistory) reader.getHistory()).save();
 

See Also:

• History
• LineReader.HISTORY_FILE
• LineReader.HISTORY_SIZE
• LineReader.HISTORY_FILE_SIZE
• LineReader.Option.HISTORY_TIMESTAMPED
• LineReader.Option.HISTORY_IGNORE_SPACE
• LineReader.Option.HISTORY_IGNORE_DUPS
• LineReader.Option.HISTORY_REDUCE_BLANKS

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	DefaultHistory.EntryImpl	Default implementation of the History.Entry interface.

Nested classes/interfaces inherited from interface org.jline.reader.History

History.Entry

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_HISTORY_FILE_SIZE	Default maximum number of history entries to keep in the history file.
static final int	DEFAULT_HISTORY_SIZE	Default maximum number of history entries to keep in memory.

Constructor Summary

Constructors

Constructor	Description
DefaultHistory()	Creates a new DefaultHistory instance.
DefaultHistory(LineReader reader)	Creates a new DefaultHistory instance and attaches it to the specified LineReader.

Method Summary

Modifier and Type	Method	Description
void	add(Instant time, String line)	Adds a new entry to the history.
protected void	addHistoryLine(Path path, String line)	Adds a history line to the specified history file.
protected void	addHistoryLine(Path path, String line, boolean checkDuplicates)	Adds a history line to the specified history file with an option to check for duplicates.
void	append(Path file, boolean incremental)	Appends history entries to the specified file.
void	attach(LineReader reader)	Attaches this history to a LineReader.
protected DefaultHistory.EntryImpl	createEntry(int index, Instant time, String line)	Create a history entry.
String	current()	Returns the text of the history entry at the current cursor position.
int	first()	Returns the index of the first element in the history.
String	get(int index)	Returns the history item at the specified index.
int	index()	Returns the current index in the history.
protected void	internalAdd(Instant time, String line)	Adds a line to the history with the specified timestamp.
protected void	internalAdd(Instant time, String line, boolean checkDuplicates)	Adds a line to the history with the specified timestamp and an option to check for duplicates.
boolean	isEmpty()	Checks if the history is empty.
ListIterator<History.Entry>	iterator(int index)	Returns a list iterator over the history entries starting at the specified index.
int	last()	Returns the index of the last element in the history.
void	load()	Loads history from the file specified by the LineReader.HISTORY_FILE variable.
protected boolean	matchPatterns(String patterns, String line)	Checks if a line matches any of the specified patterns.
boolean	moveTo(int index)	Moves the history cursor to the specified index.
void	moveToEnd()	Moves the history cursor to the end of the history buffer.
boolean	moveToFirst()	Moves the history cursor to the first entry.
boolean	moveToLast()	Moves the history cursor to the last entry.
boolean	next()	Moves the history cursor to the next (newer) entry.
boolean	previous()	Moves the history cursor to the previous (older) entry.
void	purge()	Clears the history and deletes the history file.
void	read(Path file, boolean checkDuplicates)	Reads history entries from the specified file and adds them to the current history.
void	resetIndex()	Reset index after remove
void	save()	Saves the history to the default history file.
int	size()	Returns the number of items in the history.
Spliterator<History.Entry>	spliterator()
String	toString()
protected void	trimHistory(Path path, int max)	Trims the history file to the specified maximum number of entries.
void	write(Path file, boolean incremental)	Writes the history to the specified file, optionally replacing the existing file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.jline.reader.History

add, isPersistable, iterator, reverseIterator, reverseIterator

Methods inherited from interface java.lang.Iterable

forEach

Field Details

DEFAULT_HISTORY_SIZE

public static final int DEFAULT_HISTORY_SIZE

Default maximum number of history entries to keep in memory. This value is used when the LineReader.HISTORY_SIZE variable is not set.

See Also:

• Constant Field Values

DEFAULT_HISTORY_FILE_SIZE

public static final int DEFAULT_HISTORY_FILE_SIZE

Default maximum number of history entries to keep in the history file. This value is used when the LineReader.HISTORY_FILE_SIZE variable is not set.

See Also:

• Constant Field Values

Constructor Details

DefaultHistory

public DefaultHistory()

Creates a new DefaultHistory instance.

DefaultHistory

public DefaultHistory(LineReader reader)

Creates a new DefaultHistory instance and attaches it to the specified LineReader.

Parameters:

reader - the LineReader to attach to

Method Details

attach

public void attach(LineReader reader)

Attaches this history to a LineReader.

This method associates the history with a LineReader and loads the history from the file specified by the LineReader.HISTORY_FILE variable. If the history is already attached to the given reader, this method does nothing.

Specified by:

attach in interface History

Parameters:

reader - the LineReader to attach this history to

load

public void load()
          throws IOException

Loads history from the file specified by the LineReader.HISTORY_FILE variable.

This method clears the current history and loads entries from the history file. If the file doesn't exist or can't be read, the history will be cleared. If individual lines in the history file are malformed, they will be skipped.

Specified by:

load in interface History

Throws:

IOException - if an I/O error occurs while reading the history file

read

public void read(Path file,
 boolean checkDuplicates)
          throws IOException

Reads history entries from the specified file and adds them to the current history.

Unlike load(), this method does not clear the existing history before adding entries from the file. If the file doesn't exist or can't be read, the history will be cleared. If individual lines in the history file are malformed, they will be skipped.

Specified by:

read in interface History

Parameters:

file - the file to read history from, or null to use the default history file

checkDuplicates - whether to check for and skip duplicate entries

Throws:

IOException - if an I/O error occurs while reading the history file

addHistoryLine

protected void addHistoryLine(Path path,
 String line)

Adds a history line to the specified history file.

Parameters:

path - the path to the history file

line - the line to add

addHistoryLine

protected void addHistoryLine(Path path,
 String line,
 boolean checkDuplicates)

Adds a history line to the specified history file with an option to check for duplicates.

Parameters:

path - the path to the history file

line - the line to add

checkDuplicates - whether to check for duplicate entries

purge

public void purge()
           throws IOException

Clears the history and deletes the history file.

This method removes all history entries from memory and deletes the history file if it exists.

Specified by:

purge in interface History

Throws:

IOException - if an I/O error occurs while deleting the history file

write

public void write(Path file,
 boolean incremental)
           throws IOException

Writes the history to the specified file, optionally replacing the existing file.

If the file exists, it will be deleted and recreated. If incremental is true, only entries that haven't been saved before will be written.

Specified by:

write in interface History

Parameters:

file - the file to write history to, or null to use the default history file

incremental - whether to write only new entries (true) or all entries (false)

Throws:

IOException - if an I/O error occurs while writing the history file

append

public void append(Path file,
 boolean incremental)
            throws IOException

Appends history entries to the specified file.

Unlike write(Path, boolean), this method does not delete the existing file before writing. If incremental is true, only entries that haven't been saved before will be appended.

Specified by:

append in interface History

Parameters:

file - the file to append history to, or null to use the default history file

incremental - whether to append only new entries (true) or all entries (false)

Throws:

IOException - if an I/O error occurs while appending to the history file

save

public void save()
          throws IOException

Saves the history to the default history file.

This method appends any new history entries (those that haven't been saved before) to the history file. It's typically called when the application exits to ensure that history is preserved.

Specified by:

save in interface History

Throws:

IOException - if an I/O error occurs while saving the history file

trimHistory

protected void trimHistory(Path path,
 int max)
                    throws IOException

Trims the history file to the specified maximum number of entries.

Parameters:

path - the path to the history file

max - the maximum number of entries to keep

Throws:

IOException - if an I/O error occurs

createEntry

protected DefaultHistory.EntryImpl createEntry(int index,
 Instant time,
 String line)

Create a history entry. Subclasses may override to use their own entry implementations.

Parameters:

index - index of history entry

time - entry creation time

line - the entry text

Returns:

entry object

size

public int size()

Description copied from interface: History

Returns the number of items in the history.

Specified by:

size in interface History

Returns:

the number of history items

isEmpty

public boolean isEmpty()

Description copied from interface: History

Checks if the history is empty.

Specified by:

isEmpty in interface History

Returns:

true if the history contains no items

index

public int index()

Description copied from interface: History

Returns the current index in the history.

Specified by:

index in interface History

Returns:

the current index

first

public int first()

Description copied from interface: History

Returns the index of the first element in the history.

Specified by:

first in interface History

Returns:

the index of the first history item

last

public int last()

Description copied from interface: History

Returns the index of the last element in the history.

Specified by:

last in interface History

Returns:

the index of the last history item

get

public String get(int index)

Description copied from interface: History

Returns the history item at the specified index.

Specified by:

get in interface History

Parameters:

index - the index of the history item to retrieve

Returns:

the history item at the specified index

add

public void add(Instant time,
 String line)

Adds a new entry to the history.

This method adds a new entry to the history with the specified timestamp and command text. The entry may be filtered based on various criteria such as:

• If history is disabled (LineReader.DISABLE_HISTORY is true)
• If the line starts with a space and LineReader.Option.HISTORY_IGNORE_SPACE is set
• If the line is a duplicate of the previous entry and LineReader.Option.HISTORY_IGNORE_DUPS is set
• If the line matches a pattern in LineReader.HISTORY_IGNORE

If LineReader.Option.HISTORY_INCREMENTAL is set, the history will be saved to disk after adding the entry.

Specified by:

add in interface History

Parameters:

time - the timestamp for the new entry

line - the command text for the new entry

Throws:

NullPointerException - if time or line is null

matchPatterns

protected boolean matchPatterns(String patterns,
 String line)

Checks if a line matches any of the specified patterns.

Parameters:

patterns - the patterns to match against, separated by '|'

line - the line to check

Returns:

true if the line matches any of the patterns

internalAdd

protected void internalAdd(Instant time,
 String line)

Adds a line to the history with the specified timestamp.

Parameters:

time - the timestamp for the history entry

line - the line to add

internalAdd

protected void internalAdd(Instant time,
 String line,
 boolean checkDuplicates)

Adds a line to the history with the specified timestamp and an option to check for duplicates.

Parameters:

time - the timestamp for the history entry

line - the line to add

checkDuplicates - whether to check for duplicate entries

iterator

public ListIterator<History.Entry> iterator(int index)

Description copied from interface: History

Returns a list iterator over the history entries starting at the specified index.

Specified by:

iterator in interface History

Parameters:

index - the index to start iterating from

Returns:

a list iterator over the history entries

spliterator

public Spliterator<History.Entry> spliterator()

Specified by:

spliterator in interface Iterable<History.Entry>

resetIndex

public void resetIndex()

Description copied from interface: History

Reset index after remove

Specified by:

resetIndex in interface History

moveToLast

public boolean moveToLast()

Moves the history cursor to the last entry.

This positions the cursor at the most recent history entry, which is one position before the position set by moveToEnd(). This is typically used when starting to navigate backward through history.

Specified by:

moveToLast in interface History

Returns:

true if the cursor was moved, false if there were no history entries or the cursor was already at the last entry

moveTo

public boolean moveTo(int index)

Moves the history cursor to the specified index.

This positions the cursor at the history entry with the given index, if it exists. The index is absolute, taking into account the offset of the history buffer.

Specified by:

moveTo in interface History

Parameters:

index - the absolute index to move to

Returns:

true if the cursor was moved, false if the index was out of range

moveToFirst

public boolean moveToFirst()

Moves the history cursor to the first entry.

This positions the cursor at the oldest history entry in the buffer. This is typically used when starting to navigate forward through history.

Specified by:

moveToFirst in interface History

Returns:

true if the cursor was moved, false if there were no history entries or the cursor was already at the first entry

moveToEnd

public void moveToEnd()

Moves the history cursor to the end of the history buffer.

This positions the cursor after the last history entry, which represents the current input line (not yet in history). This is the default position when not navigating through history.

Specified by:

moveToEnd in interface History

current

public String current()

Returns the text of the history entry at the current cursor position.

If the cursor is at the end of the history (after the last entry), this method returns an empty string.

Specified by:

current in interface History

Returns:

the text of the current history entry, or an empty string if at the end

previous

public boolean previous()

Moves the history cursor to the previous (older) entry.

This is typically called when the user presses the up arrow key to navigate backward through history. If the cursor is already at the first entry, this method does nothing and returns false.

Specified by:

previous in interface History

Returns:

true if the cursor was moved, false if already at the first entry

next

public boolean next()

Moves the history cursor to the next (newer) entry.

This is typically called when the user presses the down arrow key to navigate forward through history. If the cursor is already at the end of history, this method does nothing and returns false.

Specified by:

next in interface History

Returns:

true if the cursor was moved, false if already at the end of history

toString

public String toString()

Overrides:

toString in class Object