Wraps the line of text and add the new line(s) to list. - Java java.lang

Java examples for java.lang:String New Line

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Description

Wraps the line of text and add the new line(s) to list.

Demo Code

//package com.java2s;
import java.awt.FontMetrics;
import java.util.*;

public class Main {
    /**/*  ww w. jav  a  2s .co  m*/
     * Wraps the line of text and add the new line(s) to <var>list</var>.
     * @param line A line of text to be wrapped
     * @param list The list of the wrapped lines
     * @param fm FontMetrics to measure the width of the strings
     * @param maxWidth Maximum width of the line(s)
     */
    public static void wrapLineInto(String line, List<String> list,
            FontMetrics fm, int maxWidth) {
        int len = line.length();
        int width;
        while (len > 0 && (width = fm.stringWidth(line)) > maxWidth) {
            // Guess where to split the line.
            int guess = len * maxWidth / width;
            // Try to split it at a space character between words.
            String before = line.substring(0, guess).trim();

            width = fm.stringWidth(before);
            int pos;
            if (width > maxWidth) // The line is too long
                pos = findBreakBefore(line, guess);
            else { // The line is either too short or the required length
                pos = findBreakAfter(line, guess);
                if (pos != -1) { // Make sure this doesn't make it too long
                    before = line.substring(0, pos).trim();
                    if (fm.stringWidth(before) > maxWidth)
                        pos = findBreakBefore(line, guess);
                }
            }
            if (pos == -1)
                pos = guess; // Split in the middle of the word

            list.add(line.substring(0, pos).trim());
            line = line.substring(pos).trim();
            len = line.length();
        }
        if (len > 0)
            list.add(line);
    }

    /**
     * Returns the index of the first whitespace character or '-' in <var>line</var>
     * that is at or before <var>start</var>. Returns -1 if no such character is found. 
     * @param line A string of text
     * @param start Where to begin testing
     */
    public static int findBreakBefore(String line, int start) {
        for (int i = start; i >= 0; --i) {
            char c = line.charAt(i);
            if (Character.isWhitespace(c) || c == '-')
                return i;
        }
        return -1;
    }

    /**
     * Returns the index of the first whitespace character or '-' in <var>line</var>
     * that is at or after <var>start</var>. Returns -1 if no such character is found.
     * @param line A string of text
     * @param start Where to begin testing
     */
    public static int findBreakAfter(String line, int start) {
        int len = line.length();
        for (int i = start; i < len; ++i) {
            char c = line.charAt(i);
            if (Character.isWhitespace(c) || c == '-')
                return i;
        }
        return -1;
    }
}

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