src/org/jsecurity/authz/aop/PermissionAnnotationMethodInterceptor.java

/*
 * Copyright 2005-2008 Les Hazlewood
 *
 * 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 org.jsecurity.authz.aop;

import org.apache.commons.beanutils.BeanUtils;
import org.jsecurity.aop.MethodInvocation;
import org.jsecurity.authz.AuthorizationException;
import org.jsecurity.authz.UnauthorizedException;
import org.jsecurity.authz.annotation.RequiresPermissions;
import org.jsecurity.mgt.SecurityManager;
import org.jsecurity.subject.Subject;
import org.jsecurity.util.PermissionUtils;

import java.util.Set;

/**
 * @since 0.9
 * @author Les Hazlewood
 */
public class PermissionAnnotationMethodInterceptor extends AuthorizingAnnotationMethodInterceptor {

    private static final char ARRAY_CLOSE_CHAR = ']';

    public PermissionAnnotationMethodInterceptor() {
        setAnnotationClass( RequiresPermissions.class );
    }

    public PermissionAnnotationMethodInterceptor( SecurityManager securityManager ) {
        this();
        setSecurityManager( securityManager );
        init();
    }

    protected String inferTargetFromPath( Object[] methodArgs, String namePath ) throws Exception {
        int propertyStartIndex = -1;

        char[] chars = namePath.toCharArray();
        StringBuilder buf = new StringBuilder();
        //init iteration at index 1 (instead of 0).  This is because the first
        //character must be the ARRAY_OPEN_CHAR (eliminates unnecessary iteration)
        for ( int i = 1; i < chars.length; i++ ) {
            if ( chars[i] == ARRAY_CLOSE_CHAR ) {
                // skip the delimiting period after the ARRAY_CLOSE_CHAR.  The resulting
                // index is the init of the property path that we'll use with
                // BeanUtils.getProperty:
                propertyStartIndex = i + 2;
                break;
            } else {
                buf.append( chars[i] );
            }
        }

        Integer methodArgIndex = Integer.parseInt( buf.toString() );
        String beanUtilsPath = new String( chars, propertyStartIndex,
                                           chars.length - propertyStartIndex );
        Object targetValue = BeanUtils.getProperty( methodArgs[methodArgIndex], beanUtilsPath );
        return targetValue.toString();
    }

    protected Object[] getMethodArguments( MethodInvocation invocation ) {
        if ( invocation != null ) {
            return invocation.getArguments();
        } else {
            return null;
        }
    }

    protected String getAnnotationValue( MethodInvocation invocation ) {
        RequiresPermissions prAnnotation =  (RequiresPermissions)getAnnotation( invocation );
        return prAnnotation.value();
    }

    public void assertAuthorized(MethodInvocation mi) throws AuthorizationException {
        String p = getAnnotationValue( mi );
        Set<String> perms = PermissionUtils.toPermissionStrings(p);

        Subject subject = getSubject();

        if ( perms.size() == 1 ) {
            if ( !subject.isPermitted(perms.iterator().next()) ) {
                String msg = "Calling Subject does not have required permission [" + p + "].  " +
                    "Method invocation denied.";
                throw new UnauthorizedException( msg );    
            }
        } else {
            String[] permStrings = new String[perms.size()];
            permStrings = perms.toArray(permStrings);
            if ( !subject.isPermittedAll(permStrings)) {
                 String msg = "Calling Subject does not have required permissions [" + p + "].  " +
                              "Method invocation denied.";
                 throw new UnauthorizedException(msg);
            }

        }
    }


}