cn.vlabs.duckling.vwb.service.auth.policy.AuthorizationFileParser.java Source code

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Here is the source code for cn.vlabs.duckling.vwb.service.auth.policy.AuthorizationFileParser.java

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/*
 * Copyright (c) 2008-2016 Computer Network Information Center (CNIC), Chinese Academy of Sciences.
 * 
 * This file is part of Duckling project.
 *
 * 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 cn.vlabs.duckling.vwb.service.auth.policy;

import java.io.BufferedReader;
import java.io.IOException;
import java.security.Permission;
import java.security.Principal;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

import cn.vlabs.duckling.vwb.service.auth.acl.Acl;
import cn.vlabs.duckling.vwb.service.auth.acl.AclEntry;
import cn.vlabs.duckling.vwb.service.auth.permissions.VWBPermission;

/**
 * Introduction Here.
 * 
 * @date Feb 3, 2010
 * @author zzb
 */
public class AuthorizationFileParser {
    private static final Logger log = Logger.getLogger(AuthorizationFileParser.class);
    private AuthorizationTokenStream ats;

    public AuthorizationFileParser(BufferedReader reader) {
        this.ats = new AuthorizationTokenStream(reader);
    }

    public Acl parseEntry() throws AuthorizationSyntaxParseException, AuthorizationLexicParseException {
        Acl acl = new Acl();
        try {
            while (ats.hasNextToken()) {
                String grant = ats.nextUsefulToken();
                if (grant != null && grant.toLowerCase().equals("grant")) {
                    AclEntry aclEntry = new AclEntry();
                    Principal principal = parsePrincipal();
                    aclEntry.setPrincipal(principal);
                    String leftBracket = ats.nextUsefulToken();
                    if (leftBracket == null || !leftBracket.equals("{")) {
                        throw new AuthorizationSyntaxParseException(
                                "Line " + ats.getLineNum() + ", no left bracket");
                    }
                    Permission permission = parsePermission();
                    while (permission != null) {
                        aclEntry.addPermission(permission);
                        permission = parsePermission();
                    }

                    acl.addEntry(aclEntry);
                }
            }
        } catch (IOException e) {
            throw new AuthorizationLexicParseException("Lexic Parse Error, " + e.getMessage());
        }
        return acl;
    }

    private Principal parsePrincipal() throws AuthorizationSyntaxParseException, IOException {
        String principal = ats.nextUsefulToken();
        String className = ats.nextUsefulToken();
        String roleName = ats.nextUsefulToken();
        if (principal == null || !principal.toLowerCase().equals("principal")) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", principal syntax error");
        }
        if (className == null) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", className is null");
        }
        if (roleName == null) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", roleName is null");
        } else {
            roleName = StringUtils.strip(roleName, "\"");
            roleName = roleName.replace("*", "All");
        }

        try {
            Class<?> clazz = Class.forName(className);
            return ((Principal) clazz.getDeclaredConstructor(String.class).newInstance(roleName));
        } catch (ClassNotFoundException e) {
            throw new AuthorizationSyntaxParseException(
                    "Line " + ats.getLineNum() + ", ClassNotFoundException, " + e.getMessage());
        } catch (Exception e) {
            throw new AuthorizationSyntaxParseException(
                    "Line " + ats.getLineNum() + ", Exception happens, " + e.getMessage());
        }

    }

    private Permission parsePermission() throws AuthorizationSyntaxParseException, IOException {
        String perm = ats.nextUsefulToken();
        if (perm == null) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", permission syntax error");
        } else if (!perm.toLowerCase().equals("permission")) {
            String rightBracket = perm;
            if (rightBracket == null || !rightBracket.contains("}")) {
                throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", no right bracket");
            } else if (!rightBracket.contains(";")) {
                throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", no \";\" sign finded");
            }
            return null;
        }
        String className = ats.nextUsefulToken();
        String isEnd = ats.nextUsefulToken();
        if (className == null) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", className is null");
        }
        if (isEnd == null) {
            throw new AuthorizationSyntaxParseException("Line " + ats.getLineNum() + ", no operate object defined");
        } else {
            try {
                if (!isEnd.contains(";")) {
                    String oper = isEnd;
                    oper = oper.replace("\"", "");
                    oper = oper.replace(",", "");
                    isEnd = ats.nextUsefulToken();
                    if (isEnd != null && isEnd.contains(";")) {
                        String actions = isEnd.replace(";", "");
                        actions = actions.replace("\"", "");
                        Class<?> clazz = Class.forName(className, false, VWBPermission.class.getClassLoader());
                        return ((Permission) clazz
                                .getDeclaredConstructor(new Class[] { String.class, String.class })
                                .newInstance(oper, actions));
                    } else {
                        throw new AuthorizationSyntaxParseException(
                                "Line " + ats.getLineNum() + ", no \";\" sign finded");
                    }
                } else {
                    String oper = isEnd.replace(";", "");
                    oper = oper.replace("\"", "");
                    Class<?> clazz = Class.forName(className);
                    return ((Permission) clazz.getDeclaredConstructor(String.class).newInstance(oper));
                }
            } catch (ClassNotFoundException e) {
                throw new AuthorizationSyntaxParseException(
                        "Line " + ats.getLineNum() + ", ClassNotFoundException, " + e.getMessage());
            } catch (Exception e) {
                e.printStackTrace();
                throw new AuthorizationSyntaxParseException(
                        "Line " + ats.getLineNum() + ", Exception happens, " + e.getMessage());
            }
        }
    }

    public void close() {
        try {
            ats.close();
        } catch (IOException e) {
            log.error("Cloase policy file failed", e);
        }
    }
}