InputField.java

package org.h3270.host;

/*
 * Copyright (C) 2004-2006 akquinet framework solutions
 *
 * This file is part of h3270.
 *
 * h3270 is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * h3270 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with h3270; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
 * MA 02110-1301 USA
 */

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Represents a Field that allows user input.
 * 
 * @author Andre Spiegel spiegel@gnu.org
 * @version $Id: InputField.java,v 1.10 2006/10/25 11:20:09 spiegel Exp $
 */
public class InputField extends Field {

    private boolean isNumeric;
    private boolean isFocused;
    private boolean changed;

    public InputField(final Screen screen, final byte fieldCode, final int startx, final int starty, final int endx,
            final int endy, final int color, final int extHighlight) {
        super(screen, fieldCode, startx, starty, endx, endy, color, extHighlight);
        if ((fieldCode & ATTR_NUMERIC) != 0) {
            isNumeric = true;
        }
    }

    public InputField(final Screen screen, final byte fieldCode, final int startx, final int starty, final int endx,
            final int endy) {
        this(screen, fieldCode, startx, starty, endx, endy, ATTR_COL_DEFAULT, ATTR_EH_DEFAULT);
    }

    public boolean isNumeric() {
        return this.isNumeric;
    }

    public void setFocused(final boolean flag) {
        this.isFocused = flag;
    }

    public boolean isFocused() {
        return this.isFocused;
    }

    public boolean isChanged() {
        return this.changed;
    }
    
    @Override
    public boolean isWritable() {
        return true;
    }

    /**
     * Sets the value of this Field. This method does not work for multiline fields; use setValue(int, String) instead.
     */
    public void setValue(final String newValue) {
        if (this.isMultiline()) {
            throw new RuntimeException("use setValue(int, String) for multiline field");
        }
        if (this.value == null) {
            getValue();
        }
        if (!newValue.equals(trim(this.value))) {
            final int width = endx - startx + 1;
            if (newValue.length() > width) {
                this.value = newValue.substring(0, width);
            } else {
                this.value = newValue;
            }
            changed = true;
        }
    }

    private static final Pattern LINE_PATTERN = Pattern.compile(".*\n", Pattern.MULTILINE);

    /**
     * Sets the value of one of the lines in a multi-line field.
     * 
     * @param lineNumber
     *            the number of the line to be changed, starting at zero
     * @param newValue
     *            The new value for this line. It is not supposed to have a trailing newline.
     */
    public void setValue(final int lineNumber, final String newValue) {
        if (this.value == null) {
            getValue();
        }
        final StringBuffer result = new StringBuffer();
        final Matcher m = LINE_PATTERN.matcher(this.value);
        for (int i = 0; i < lineNumber; i++) {
            m.find();
            result.append(m.group(0));
        }
        result.append(trim(newValue));
        if (lineNumber < getHeight() - 1) {
            result.append("\n");
            m.find();
            result.append(this.value.substring(m.end()));
        }
        final String val = result.toString();
        if (!val.equals(this.value)) {
            this.value = val;
            changed = true;
        }
    }

    private static final Pattern TRIM_PATTERN = Pattern.compile("^[\\x00 _]*(.*?)[\\x00 _]*$", 0);

    /**
     * Returns a string that is the same as the argument, with leading and trailing ASCII NUL characters, blanks and
     * underscores removed.
     */
    public static String trim(final String value) {
        final Matcher m = TRIM_PATTERN.matcher(value);
        if (m.matches()) {
            return m.group(1).replace((char) 0, ' ');
        } else {
            return value;
        }
    }

}