IOSafeTerminalAdapter.java

/*
 * This file is part of lanterna (http://code.google.com/p/lanterna/).
 *
 * lanterna is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 2010-2017 Martin Berglund
 */
package com.googlecode.lanterna.terminal;

import com.googlecode.lanterna.SGR;
import com.googlecode.lanterna.TerminalPosition;
import com.googlecode.lanterna.TerminalSize;
import com.googlecode.lanterna.TextColor;
import com.googlecode.lanterna.graphics.TextGraphics;
import com.googlecode.lanterna.input.KeyStroke;
import java.io.IOException;
import java.util.concurrent.TimeUnit;

/**
 * This class exposes methods for converting a terminal into an IOSafeTerminal. There are two options available, either
 * one that will convert any IOException to a RuntimeException (and re-throw it) or one that will silently swallow any
 * IOException (and return null in those cases the method has a non-void return type).
 * @author Martin
 */
public class IOSafeTerminalAdapter implements IOSafeTerminal {
    private interface ExceptionHandler {
        void onException(IOException e);
    }
    
    private static class ConvertToRuntimeException implements ExceptionHandler {
        @Override
        public void onException(IOException e) {
            throw new RuntimeException(e);
        }
    }
    
    private static class DoNothingAndOrReturnNull implements ExceptionHandler {
        @Override
        public void onException(IOException e) { }
    }
    
    /**
     * Creates a wrapper around a Terminal that exposes it as a IOSafeTerminal. If any IOExceptions occur, they will be
     * wrapped by a RuntimeException and re-thrown.
     * @param terminal Terminal to wrap
     * @return IOSafeTerminal wrapping the supplied terminal
     */
    public static IOSafeTerminal createRuntimeExceptionConvertingAdapter(Terminal terminal) {
        if (terminal instanceof ExtendedTerminal) { // also handle Runtime-type:
            return createRuntimeExceptionConvertingAdapter((ExtendedTerminal)terminal);
        } else {
            return new IOSafeTerminalAdapter(terminal, new ConvertToRuntimeException());
        }
    }
    
    /**
     * Creates a wrapper around an ExtendedTerminal that exposes it as a IOSafeExtendedTerminal.
     * If any IOExceptions occur, they will be wrapped by a RuntimeException and re-thrown.
     * @param terminal Terminal to wrap
     * @return IOSafeTerminal wrapping the supplied terminal
     */
    public static IOSafeExtendedTerminal createRuntimeExceptionConvertingAdapter(ExtendedTerminal terminal) {
        return new IOSafeTerminalAdapter.Extended(terminal, new ConvertToRuntimeException());
    }
    
    /**
     * Creates a wrapper around a Terminal that exposes it as a IOSafeTerminal. If any IOExceptions occur, they will be
     * silently ignored and for those method with a non-void return type, null will be returned.
     * @param terminal Terminal to wrap
     * @return IOSafeTerminal wrapping the supplied terminal
     */
    public static IOSafeTerminal createDoNothingOnExceptionAdapter(Terminal terminal) {
        if (terminal instanceof ExtendedTerminal) { // also handle Runtime-type:
            return createDoNothingOnExceptionAdapter((ExtendedTerminal)terminal);
        } else {
            return new IOSafeTerminalAdapter(terminal, new DoNothingAndOrReturnNull());
        }
    }

    /**
     * Creates a wrapper around an ExtendedTerminal that exposes it as a IOSafeExtendedTerminal.
     * If any IOExceptions occur, they will be silently ignored and for those method with a 
     * non-void return type, null will be returned.
     * @param terminal Terminal to wrap
     * @return IOSafeTerminal wrapping the supplied terminal
     */
    public static IOSafeExtendedTerminal createDoNothingOnExceptionAdapter(ExtendedTerminal terminal) {
        return new IOSafeTerminalAdapter.Extended(terminal, new DoNothingAndOrReturnNull());
    }

    private final Terminal backend;
    final ExceptionHandler exceptionHandler;

    @SuppressWarnings("WeakerAccess")
    public IOSafeTerminalAdapter(Terminal backend, ExceptionHandler exceptionHandler) {
        this.backend = backend;
        this.exceptionHandler = exceptionHandler;
    }

    @Override
    public void enterPrivateMode() {
        try {
            backend.enterPrivateMode();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void exitPrivateMode() {
        try {
            backend.exitPrivateMode();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void clearScreen() {
        try {
            backend.clearScreen();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void setCursorPosition(int x, int y) {
        try {
            backend.setCursorPosition(x, y);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void setCursorPosition(TerminalPosition position) {
        try {
            backend.setCursorPosition(position);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public TerminalPosition getCursorPosition() {
        try {
            return backend.getCursorPosition();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    @Override
    public void setCursorVisible(boolean visible) {
        try {
            backend.setCursorVisible(visible);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void putCharacter(char c) {
        try {
            backend.putCharacter(c);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public TextGraphics newTextGraphics() {
        try {
            return backend.newTextGraphics();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    @Override
    public void enableSGR(SGR sgr) {
        try {
            backend.enableSGR(sgr);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void disableSGR(SGR sgr) {
        try {
            backend.disableSGR(sgr);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void resetColorAndSGR() {
        try {
            backend.resetColorAndSGR();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void setForegroundColor(TextColor color) {
        try {
            backend.setForegroundColor(color);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void setBackgroundColor(TextColor color) {
        try {
            backend.setBackgroundColor(color);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void addResizeListener(TerminalResizeListener listener) {
        backend.addResizeListener(listener);
    }

    @Override
    public void removeResizeListener(TerminalResizeListener listener) {
        backend.removeResizeListener(listener);
    }

    @Override
    public TerminalSize getTerminalSize() {
        try {
            return backend.getTerminalSize();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    @Override
    public byte[] enquireTerminal(int timeout, TimeUnit timeoutUnit) {
        try {
            return backend.enquireTerminal(timeout, timeoutUnit);
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    @Override
    public void bell() {
        try {
            backend.bell();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void flush() {
        try {
            backend.flush();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public void close() {
        try {
            backend.close();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
    }

    @Override
    public KeyStroke pollInput() {
        try {
            return backend.pollInput();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    @Override
    public KeyStroke readInput() {
        try {
            return backend.readInput();
        }
        catch(IOException e) {
            exceptionHandler.onException(e);
        }
        return null;
    }

    /**
     * This class exposes methods for converting an extended terminal into an IOSafeExtendedTerminal.
     */
    public static class Extended extends IOSafeTerminalAdapter implements IOSafeExtendedTerminal {
        private final ExtendedTerminal backend;
        
        public Extended(ExtendedTerminal backend, ExceptionHandler exceptionHandler) {
            super(backend, exceptionHandler);
            this.backend = backend;
        }

        @Override
        public void setTerminalSize(int columns, int rows) {
            try {
                backend.setTerminalSize(columns, rows);
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void setTitle(String title) {
            try {
                backend.setTitle(title);
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void pushTitle() {
            try {
                backend.pushTitle();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void popTitle() {
            try {
                backend.popTitle();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void iconify() {
            try {
                backend.iconify();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void deiconify() {
            try {
                backend.deiconify();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void maximize() {
            try {
                backend.maximize();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void unmaximize() {
            try {
                backend.unmaximize();
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void setMouseCaptureMode(MouseCaptureMode mouseCaptureMode) {
            try {
                backend.setMouseCaptureMode(mouseCaptureMode);
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

        @Override
        public void scrollLines(int firstLine, int lastLine, int distance) {
            try {
                backend.scrollLines(firstLine, lastLine, distance);
            }
            catch(IOException e) {
                exceptionHandler.onException(e);
            }
        }

    }
}