jp.xet.uncommons.wicket.model.AbbreviateStringModel.java Source code

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Here is the source code for jp.xet.uncommons.wicket.model.AbbreviateStringModel.java

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/*
 * Copyright 2011 Daisuke Miyamoto.
 * Created on 2012/03/07
 *
 * Licensed 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 jp.xet.uncommons.wicket.model;

import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.model.IModel;

/**
 * TODO for daisuke
 * 
 * @since 1.2
 * @version $Id$
 * @author daisuke
 */
@SuppressWarnings("serial")
public class AbbreviateStringModel extends AbstractReadOnlyModel<String> {

    private final IModel<String> source;

    private final int maxWidth;

    /**
     * ??
     * 
     * @param source ?
     * @param maxWidth 
     */
    public AbbreviateStringModel(IModel<String> source, int maxWidth) {
        this.source = source;
        this.maxWidth = maxWidth;
    }

    @Override
    public void detach() {
        source.detach();
        super.detach();
    }

    @Override
    public String getObject() {
        return abbreviate(source.getObject(), maxWidth);
    }

    /**
     * <p>Abbreviates a String using ellipses. This will turn
     * "Now is the time for all good men" into "Now is the time for..."</p>
     *
     * <p>Specifically:
     * <ul>
     *   <li>If <code>str</code> is less than <code>maxWidth</code> characters
     *       long, return it.</li>
     *   <li>Else abbreviate it to <code>(substring(str, 0, max-3) + "...")</code>.</li>
     *   <li>If <code>maxWidth</code> is less than <code>4</code>, throw an
     *       <code>IllegalArgumentException</code>.</li>
     *   <li>In no case will it return a String of length greater than
     *       <code>maxWidth</code>.</li>
     * </ul>
     * </p>
     *
     * <pre>
     * StringUtils.abbreviate(null, *)      = null
     * StringUtils.abbreviate("", 4)        = ""
     * StringUtils.abbreviate("abcdefg", 6) = "abc..."
     * StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
     * StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
     * StringUtils.abbreviate("abcdefg", 4) = "a..."
     * StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param maxWidth  maximum length of result String, must be at least 4
     * @return abbreviated String, <code>null</code> if null String input
     * @throws IllegalArgumentException if the width is too small
     */
    protected String abbreviate(String str, int maxWidth) {
        return abbreviate(str, 0, maxWidth);
    }

    /**
     * <p>Abbreviates a String using ellipses. This will turn
     * "Now is the time for all good men" into "...is the time for..."</p>
     *
     * <p>Works like <code>abbreviate(String, int)</code>, but allows you to specify
     * a "left edge" offset.  Note that this left edge is not necessarily going to
     * be the leftmost character in the result, or the first character following the
     * ellipses, but it will appear somewhere in the result.
     *
     * <p>In no case will it return a String of length greater than
     * <code>maxWidth</code>.</p>
     *
     * <pre>
     * StringUtils.abbreviate(null, *, *)                = null
     * StringUtils.abbreviate("", 0, 4)                  = ""
     * StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
     * StringUtils.abbreviate("abcdefghijklmno", 0, 10)  = "abcdefg..."
     * StringUtils.abbreviate("abcdefghijklmno", 1, 10)  = "abcdefg..."
     * StringUtils.abbreviate("abcdefghijklmno", 4, 10)  = "abcdefg..."
     * StringUtils.abbreviate("abcdefghijklmno", 5, 10)  = "...fghi..."
     * StringUtils.abbreviate("abcdefghijklmno", 6, 10)  = "...ghij..."
     * StringUtils.abbreviate("abcdefghijklmno", 8, 10)  = "...ijklmno"
     * StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
     * StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
     * StringUtils.abbreviate("abcdefghij", 0, 3)        = IllegalArgumentException
     * StringUtils.abbreviate("abcdefghij", 5, 6)        = IllegalArgumentException
     * </pre>
     *
     * @param str  the String to check, may be null
     * @param offset  left edge of source String
     * @param maxWidth  maximum length of result String, must be at least 4
     * @return abbreviated String, <code>null</code> if null String input
     * @throws IllegalArgumentException if the width is too small
     */
    protected String abbreviate(String str, int offset, int maxWidth) {
        if (str == null) {
            return null;
        }
        if (maxWidth < 4) {
            throw new IllegalArgumentException("Minimum abbreviation width is 4");
        }
        if (str.length() <= maxWidth) {
            return str;
        }
        if (offset > str.length()) {
            offset = str.length();
        }
        if ((str.length() - offset) < (maxWidth - 3)) {
            offset = str.length() - (maxWidth - 3);
        }
        if (offset <= 4) {
            return str.substring(0, maxWidth - 3) + "...";
        }
        if (maxWidth < 7) {
            throw new IllegalArgumentException("Minimum abbreviation width with offset is 7");
        }
        if ((offset + (maxWidth - 3)) < str.length()) {
            return "..." + abbreviate(str.substring(offset), maxWidth - 3);
        }
        return "..." + str.substring(str.length() - (maxWidth - 3));
    }
}