edu.uci.ics.jung.visualization.util.LabelWrapper.java Source code

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Here is the source code for edu.uci.ics.jung.visualization.util.LabelWrapper.java
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/*
 * Copyright (c) 2005, the JUNG Project and the Regents of the University of
 * California All rights reserved.
 *
 * This software is open-source under the BSD license; see either "license.txt"
 * or http://jung.sourceforge.net/license.txt for a description.
 *
 */
package edu.uci.ics.jung.visualization.util;

import org.apache.commons.collections15.Transformer;

/**
 * A utility to wrap long lines, creating html strings
 * with line breaks at a settable max line length
 * 
 * @author Tom Nelson - tomnelson@dev.java.net
 *
 */
public class LabelWrapper implements Transformer<String, String> {

    int lineLength;
    public static final String breaker = "<p>";

    /**
     * Create an instance with default line break length = 10
     *
     */
    public LabelWrapper() {
        this(10);
    }

    /**
     * Create an instance with passed line break length
     * @param lineLength the max length for lines
     */
    public LabelWrapper(int lineLength) {
        this.lineLength = lineLength;
    }

    /**
     * call 'wrap' to transform the passed String
     */
    public String transform(String str) {
        if (str != null) {
            return wrap(str);
        } else {
            return null;
        }
    }

    /**
     * line-wrap the passed String as an html string with
     * break Strings inserted.
     * 
     * @param str
     * @return
     */
    private String wrap(String str) {
        StringBuilder buf = new StringBuilder(str);
        int len = lineLength;
        while (len < buf.length()) {
            int idx = buf.lastIndexOf(" ", len);
            if (idx != -1) {
                buf.replace(idx, idx + 1, breaker);
                len = idx + breaker.length() + lineLength;
            } else {
                buf.insert(len, breaker);
                len += breaker.length() + lineLength;
            }
        }
        buf.insert(0, "<html>");
        return buf.toString();
    }

    public static void main(String[] args) {
        String[] lines = { "This is a line with many short words that I will break into shorter lines.",
                "thisisalinewithnobreakssowhoknowswhereitwillwrap", "short line" };
        LabelWrapper w = new LabelWrapper(10);
        for (int i = 0; i < lines.length; i++) {
            System.err.println("from " + lines[i] + " to " + w.wrap(lines[i]));
        }
    }
}