/*

 * Copyright (c) 1998, 2004, 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 sun.security.util;

import java.net.URI;

import java.net.URISyntaxException;

import java.security.GeneralSecurityException;

/**

 * A utility class to expand properties embedded in a string.

 * Strings of the form ${some.property.name} are expanded to

 * be the value of the property. Also, the special ${/} property

 * is expanded to be the same as file.separator. If a property

 * is not set, a GeneralSecurityException will be thrown.

 *

 * @author Roland Schemers

 */

public class PropertyExpander {

    public static class ExpandException extends GeneralSecurityException {

        private static final long serialVersionUID = -7941948581406161702L;

        public ExpandException(String msg) {

            super(msg);

        }

    }

    public static String expand(String value)

        throws ExpandException

    {

        return expand(value, false);

    }

     public static String expand(String value, boolean encodeURL)

         throws ExpandException

     {

        if (value == null)

            return null;

        int p = value.indexOf("${", 0);

        // no special characters

        if (p == -1) return value;

        StringBuffer sb = new StringBuffer(value.length());

        int max = value.length();

        int i = 0;  // index of last character we copied

    scanner:

        while (p < max) {

            if (p > i) {

                // copy in anything before the special stuff

                sb.append(value.substring(i, p));

                i = p;

            }

            int pe = p+2;

            // do not expand ${{ ... }}

            if (pe < max && value.charAt(pe) == '{') {

                pe = value.indexOf("}}", pe);

                if (pe == -1 || pe+2 == max) {

                    // append remaining chars

                    sb.append(value.substring(p));

                    break scanner;

                } else {

                    // append as normal text

                    pe++;

                    sb.append(value.substring(p, pe+1));

                }

            } else {

                while ((pe < max) && (value.charAt(pe) != '}')) {

                    pe++;

                }

                if (pe == max) {

                    // no matching '}' found, just add in as normal text

                    sb.append(value.substring(p, pe));

                    break scanner;

                }

                String prop = value.substring(p+2, pe);

                if (prop.equals("/")) {

                    sb.append(java.io.File.separatorChar);

                } else {

                    String val = System.getProperty(prop);

                    if (val != null) {

                        if (encodeURL) {

                            // encode 'val' unless it's an absolute URI

                            // at the beginning of the string buffer

                            try {

                                if (sb.length() > 0 ||

                                    !(new URI(val)).isAbsolute()) {

                                    val = sun.net.www.ParseUtil.encodePath(val);

                                }

                            } catch (URISyntaxException use) {

                                val = sun.net.www.ParseUtil.encodePath(val);

                            }

                        }

                        sb.append(val);

                    } else {

                        throw new ExpandException(

                                             "unable to expand property " +

                                             prop);

                    }

                }

            }

            i = pe+1;

            p = value.indexOf("${", i);

            if (p == -1) {

                // no more to expand. copy in any extra

                if (i < max) {

                    sb.append(value.substring(i, max));

                }

                // break out of loop

                break scanner;

            }

        }

        return sb.toString();

    }

}