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/*
* Copyright (c) 2016, Stein Eldar Johnsen
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 net.morimekta.console.terminal;
import com.google.common.collect.ImmutableList;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import static net.morimekta.console.chr.CharUtil.printableWidth;
import static net.morimekta.console.chr.Control.CURSOR_ERASE;
import static net.morimekta.console.chr.Control.UP;
import static net.morimekta.console.chr.Control.cursorDown;
import static net.morimekta.console.chr.Control.cursorRight;
import static net.morimekta.console.chr.Control.cursorUp;
/**
* Class that holds a set of lines, that are printed to the terminal, and
* methods to dynamically update those buffer. It will keep the cursor at
* the bottom line (end of printed line) for easy continuation.
*
* The class acts as a wrapper around a {@link Terminal} instance, and
* makes sure that a list of lines can be updated and printed properly to
* the terminal in the most efficient order.
*
* Example uses are for showing a list of {@link Progress}'es, or
* handling the internals of a {@link InputSelection}.
*/
public class LineBuffer {
private final Terminal terminal;
private final ArrayList buffer;
/**
* Create a LineBuffer instance.
*
* @param terminal The terminal to wrap.
*/
public LineBuffer(Terminal terminal) {
this.terminal = terminal;
this.buffer = new ArrayList<>();
}
/**
* @return Number of lines in the buffer.
*/
public int count() {
return buffer.size();
}
/**
* Add new lines to the end of the buffer, and print them out.
*
* @param lines The lines to add.
*/
public void add(String ... lines) {
add(ImmutableList.copyOf(lines));
}
/**
* Add new lines to the end of the buffer, and print them out.
*
* @param lines The lines to add.
*/
public void add(Collection lines) {
for (String line : lines) {
buffer.add(line);
terminal.println(line);
}
}
/**
* Update a number of lines starting at a specific offset.
*
* @param offset The line offset (0-indexed to count).
* @param lines The new line content.
*/
public void update(int offset, String... lines) {
update(offset, ImmutableList.copyOf(lines));
}
/**
* Update a number of lines starting at a specific offset.
*
* @param offset The line offset (0-indexed to count).
* @param lines The new line content.
*/
public void update(int offset, List lines) {
if (lines.isEmpty()) {
throw new IllegalArgumentException("Empty line set");
}
if (offset >= count() || offset < 0) {
throw new IndexOutOfBoundsException("Index: " + offset + ", Size: " + count());
}
int up = count() - offset - 1;
for (int i = 0; i < lines.size(); ++i) {
String line = lines.get(i);
if (i == 0) {
terminal.print("\r");
if (up > 0) {
terminal.print(cursorUp(up));
}
} else {
terminal.println();
--up;
}
String old = offset + i < buffer.size()
? buffer.get(offset + i)
: null;
buffer.set(offset + i, line);
if (line.equals(old) && !line.isEmpty()) {
// No change.
continue;
}
terminal.print(CURSOR_ERASE);
terminal.print(line);
}
// Move the cursor back to the end of the last line.
if (up > 0) {
terminal.format("\r%s%s",
cursorDown(up),
cursorRight(printableWidth(lastLine())));
}
}
/**
* Clear the entire buffer, and the terminal area it represents.
*/
public void clear() {
if (buffer.size() > 0) {
terminal.format("\r%s", CURSOR_ERASE);
for (int i = 1; i < buffer.size(); ++i) {
terminal.format("%s%s", UP, CURSOR_ERASE);
}
buffer.clear();
}
}
/**
* Clear the last N lines, and move the cursor to the end of the last
* remaining line.
*
* @param N Number of lines to clear.
*/
public void clearLast(int N) {
if (N < 1) {
throw new IllegalArgumentException("Unable to clear " + N + " lines");
}
if (N > count()) {
throw new IllegalArgumentException("Count: " + N + ", Size: " + count());
}
if (N == count()) {
clear();
return;
}
terminal.format("\r%s", CURSOR_ERASE);
buffer.remove(buffer.size() - 1);
for (int i = 1; i < N; ++i) {
terminal.format("%s%s", UP, CURSOR_ERASE);
buffer.remove(buffer.size() - 1);
}
terminal.format("%s\r%s",
UP,
cursorRight(printableWidth(lastLine())));
}
/**
* @return The current set of lines shown.
*/
public List lines() {
return ImmutableList.copyOf(buffer);
}
/**
* @return The content of the last line in the buffer.
*/
private String lastLine() {
return buffer.get(buffer.size() - 1);
}
}