Java example source code file (Util.java)

This example Java source code file (Util.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

exception, hashset, set, string, stringbuilder, stringtokenizer, util

The Util.java Java example source code

/*
 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.tools.sjavac;

import java.io.File;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
import java.util.StringTokenizer;

/**
 * Utilities.
 *
 * <p>This is NOT part of any supported API.
 * If you write code that depends on this, you do so at your own
 * risk.  This code and its internal interfaces are subject to change
 * or deletion without notice.</b>

 */
public class Util {

    public static String toFileSystemPath(String pkgId) {
        if (pkgId == null || pkgId.length()==0) return null;
        String pn;
        if (pkgId.charAt(0) == ':') {
            // When the module is the default empty module.
            // Do not prepend the module directory, because there is none.
            // Thus :java.foo.bar translates to java/foo/bar (or \)
            pn = pkgId.substring(1).replace('.',File.separatorChar);
        } else {
            // There is a module. Thus jdk.base:java.foo.bar translates
            // into jdk.base/java/foo/bar
            int cp = pkgId.indexOf(':');
            String mn = pkgId.substring(0,cp);
            pn = mn+File.separatorChar+pkgId.substring(cp+1).replace('.',File.separatorChar);
        }
        return pn;
    }

    public static String justPackageName(String pkgName) {
        int c = pkgName.indexOf(":");
        assert(c != -1);
        return pkgName.substring(c+1);
    }

    public static String extractStringOption(String opName, String s) {
        int p = s.indexOf(opName+"=");
        if (p == -1) return null;
        p+=opName.length()+1;
        int pe = s.indexOf(',', p);
        if (pe == -1) pe = s.length();
        return s.substring(p, pe);
    }

    public static int extractIntOption(String opName, String s) {
        int p = s.indexOf(opName+"=");
        if (p == -1) return 0;
        p+=opName.length()+1;
        int pe = s.indexOf(',', p);
        if (pe == -1) pe = s.length();
        int v = 0;
        try {
            v = Integer.parseInt(s.substring(p, pe));
        } catch (Exception e) {}
        return v;
    }

    /**
     * Clean out unwanted sub options supplied inside a primary option.
     * For example to only had portfile remaining from:
     *    settings="--server:id=foo,portfile=bar"
     * do settings = cleanOptions("--server:",Util.set("-portfile"),settings);
     *    now settings equals "--server:portfile=bar"
     *
     * @param optionPrefix The option name, including colon, eg --server:
     * @param allowsSubOptions A set of the allowed sub options, id portfile etc.
     * @param s The option settings string.
     */
    public static String cleanSubOptions(String optionPrefix, Set<String> allowedSubOptions, String s) {
        StringBuilder sb = new StringBuilder();
        if (!s.startsWith(optionPrefix)) return "";
        StringTokenizer st = new StringTokenizer(s.substring(optionPrefix.length()), ",");
        while (st.hasMoreTokens()) {
            String o = st.nextToken();
            int p = o.indexOf('=');
            if (p>0) {
                String key = o.substring(0,p);
                String val = o.substring(p+1);
                if (allowedSubOptions.contains(key)) {
                    if (sb.length() > 0) sb.append(',');
                    sb.append(key+"="+val);
                }
            }
        }
        return sb.toString();
    }

    /**
     * Convenience method to create a set with strings.
     */
    public static Set<String> set(String... ss) {
        Set<String> set = new HashSet();
        set.addAll(Arrays.asList(ss));
        return set;
    }

    /**
     * Normalize windows drive letter paths to upper case to enable string
     * comparison.
     *
     * @param file File name to normalize
     * @return The normalized string if file has a drive letter at the beginning,
     *         otherwise the original string.
     */
    public static String normalizeDriveLetter(String file) {
        if (file.length() > 2 && file.charAt(1) == ':') {
            return Character.toUpperCase(file.charAt(0)) + file.substring(1);
        } else if (file.length() > 3 && file.charAt(0) == '*'
                   && file.charAt(2) == ':') {
            // Handle a wildcard * at the beginning of the string.
            return file.substring(0, 1) + Character.toUpperCase(file.charAt(1))
                   + file.substring(2);
        }
        return file;
    }

    /**
     * Locate the setting for the server properties.
     */
    public static String findServerSettings(String[] args) {
        for (String s : args) {
            if (s.startsWith("--server:")) {
                return s;
            }
        }
        return null;
    }
}