stringutils.java

velocity官方工具包 包括各种JAR包 示例 文档等

package org.apache.velocity.util;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.    
 */

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;


/**
 * This class provides some methods for dynamically
 * invoking methods in objects, and some string
 * manipulation methods used by torque. The string
 * methods will soon be moved into the turbine
 * string utilities class.
 *
 *  @author <a href="mailto:[e-mail]">Jason van Zyl</a>
 *  @author <a href="mailto:[e-mail]">Daniel Rall</a>
 *  @version $Id: StringUtils.java 463298 2006-10-12 16:10:32Z henning $
 */
public class StringUtils
{
    /**
     * Line separator for the OS we are operating on.
     */
    private static final String EOL = System.getProperty("line.separator");

    /**
     * Concatenates a list of objects as a String.
     *
     * @param list The list of objects to concatenate.
     * @return     A text representation of the concatenated objects.
     */
    public String concat(List list)
    {
        StringBuffer sb = new StringBuffer();
        int size = list.size();

        for (int i = 0; i < size; i++)
        {
            sb.append(list.get(i).toString());
        }
        return sb.toString();
    }

    /**
     * Return a package name as a relative path name
     *
     * @param pckge package name to convert to a directory.
     * @return String directory path.
     */
    static public String getPackageAsPath(String pckge)
    {
        return pckge.replace( '.', File.separator.charAt(0) ) + File.separator;
    }

    /**
     * <p>
     * Remove underscores from a string and replaces first
     * letters with capitals.  Other letters are changed to lower case.
     * </p>
     *
     * <p>
     * For example <code>foo_bar</code> becomes <code>FooBar</code>
     * but <code>foo_barBar</code> becomes <code>FooBarbar</code>.
     * </p>
     *
     * @param data string to remove underscores from.
     * @return String
     * @deprecated Use the org.apache.commons.util.StringUtils class
     * instead.  Using its firstLetterCaps() method in conjunction
     * with a StringTokenizer will achieve the same result.
     */
    static public String removeUnderScores (String data)
    {
        String temp = null;
        StringBuffer out = new StringBuffer();
        temp = data;

        StringTokenizer st = new StringTokenizer(temp, "_");

        while (st.hasMoreTokens())
        {
            String element = (String) st.nextElement();
            out.append ( firstLetterCaps(element));
        }

        return out.toString();
    }

    /**
     * <p>
     *  'Camels Hump' replacement of underscores.
     * </p>
     *
     * <p>
     * Remove underscores from a string but leave the capitalization of the
     * other letters unchanged.
     * </p>
     *
     * <p>
     * For example <code>foo_barBar</code> becomes <code>FooBarBar</code>.
     * </p>
     *
     * @param data string to hump
     * @return String
     */
    static public String removeAndHump (String data)
    {
        return removeAndHump(data,"_");
    }

    /**
     * <p>
     * 'Camels Hump' replacement.
     * </p>
     *
     * <p>
     * Remove one string from another string but leave the capitalization of the
     * other letters unchanged.
     * </p>
     *
     * <p>
     * For example, removing "_" from <code>foo_barBar</code> becomes <code>FooBarBar</code>.
     * </p>
     *
     * @param data string to hump
     * @param replaceThis string to be replaced
     * @return String
     */
    static public String removeAndHump (String data,String replaceThis)
    {
        String temp = null;
        StringBuffer out = new StringBuffer();
        temp = data;

        StringTokenizer st = new StringTokenizer(temp, replaceThis);

        while (st.hasMoreTokens())
        {
            String element = (String) st.nextElement();
            out.append ( capitalizeFirstLetter(element));
        }//while

        return out.toString();
    }

    /**
     * <p>
     *  Makes the first letter caps and the rest lowercase.
     * </p>
     *
     * <p>
     *  For example <code>fooBar</code> becomes <code>Foobar</code>.
     * </p>
     *
     * @param data capitalize this
     * @return String
     */
    static public String firstLetterCaps ( String data )
    {
        String firstLetter = data.substring(0,1).toUpperCase();
        String restLetters = data.substring(1).toLowerCase();
        return firstLetter + restLetters;
    }

    /**
     * <p>
     * Capitalize the first letter but leave the rest as they are.
     * </p>
     *
     * <p>
     *  For example <code>fooBar</code> becomes <code>FooBar</code>.
     * </p>
     *
     * @param data capitalize this
     * @return String
     */
    static public String capitalizeFirstLetter ( String data )
    {
        String firstLetter = data.substring(0,1).toUpperCase();
        String restLetters = data.substring(1);
        return firstLetter + restLetters;
    }

    /**
     * Create a string array from a string separated by delim
     *
     * @param line the line to split
     * @param delim the delimter to split by
     * @return a string array of the split fields
     */
    public static String [] split(String line, String delim)
    {
        List list = new ArrayList();
        StringTokenizer t = new StringTokenizer(line, delim);
        while (t.hasMoreTokens())
        {
            list.add(t.nextToken());
        }
        return (String []) list.toArray(new String[list.size()]);
    }

    /**
     * Chop i characters off the end of a string.
     * This method assumes that any EOL characters in String s
     * and the platform EOL will be the same.
     * A 2 character EOL will count as 1 character.
     *
     * @param s String to chop.
     * @param i Number of characters to chop.
     * @return String with processed answer.
     */
    public static String chop(String s, int i)
    {
        return chop(s, i, EOL);
    }

    /**
     * Chop i characters off the end of a string.
     * A 2 character EOL will count as 1 character.
     *
     * @param s String to chop.
     * @param i Number of characters to chop.
     * @param eol A String representing the EOL (end of line).
     * @return String with processed answer.
     */
    public static String chop(String s, int i, String eol)
    {
        if ( i == 0 || s == null || eol == null )
        {
           return s;
        }

        int length = s.length();

        /*
         * if it is a 2 char EOL and the string ends with
         * it, nip it off.  The EOL in this case is treated like 1 character
         */
        if ( eol.length() == 2 && s.endsWith(eol ))
        {
            length -= 2;
            i -= 1;
        }

        if ( i > 0)
        {
            length -= i;
        }

        if ( length < 0)
        {
            length = 0;
        }

        return s.substring( 0, length);
    }

    /**
     * @param argStr
     * @param vars
     * @return Substituted String.
     */
    public static StringBuffer stringSubstitution( String argStr,
                                                   Hashtable vars )
    {
        return stringSubstitution( argStr, (Map) vars );
    }

    /**
     * Perform a series of substitutions. The substitions
     * are performed by replacing $variable in the target
     * string with the value of provided by the key "variable"
     * in the provided hashtable.
     *
     * @param argStr target string
     * @param vars name/value pairs used for substitution
     * @return String target string with replacements.
     */
    public static StringBuffer stringSubstitution(String argStr,
            Map vars)
    {
        StringBuffer argBuf = new StringBuffer();

        for (int cIdx = 0 ; cIdx < argStr.length();)
        {
            char ch = argStr.charAt(cIdx);

            switch (ch)
            {
                case '$':
                    StringBuffer nameBuf = new StringBuffer();
                    for (++cIdx ; cIdx < argStr.length(); ++cIdx)
                    {
                        ch = argStr.charAt(cIdx);
                        if (ch == '_' || Character.isLetterOrDigit(ch))
                            nameBuf.append(ch);
                        else
                            break;