org.pentaho.di.core.auth.kerberos.LoginContextInvocationHandler.java Source code

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Here is the source code for org.pentaho.di.core.auth.kerberos.LoginContextInvocationHandler.java

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/*! ******************************************************************************
 *
 * Pentaho Data Integration
 *
 * Copyright (C) 2002-2013 by Pentaho : http://www.pentaho.com
 *
 *******************************************************************************
 *
 * 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.pentaho.di.core.auth.kerberos;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import javax.security.auth.Subject;
import javax.security.auth.login.LoginContext;

import org.apache.commons.lang.ClassUtils;

public class LoginContextInvocationHandler<T> implements InvocationHandler {
    private final T delegate;
    private final LoginContext loginContext;
    private final Set<Class<?>> interfacesToDelegate;

    public LoginContextInvocationHandler(T delegate, LoginContext loginContext) {
        this(delegate, loginContext, new HashSet<Class<?>>());
    }

    public LoginContextInvocationHandler(T delegate, LoginContext loginContext,
            Set<Class<?>> interfacesToDelegate) {
        this.delegate = delegate;
        this.loginContext = loginContext;
        this.interfacesToDelegate = interfacesToDelegate;
    }

    @SuppressWarnings("unchecked")
    public static <T> T forObject(T delegate, LoginContext loginContext, Set<Class<?>> interfacesToDelegate) {
        return (T) Proxy.newProxyInstance(delegate.getClass().getClassLoader(),
                ((List<Class<?>>) ClassUtils.getAllInterfaces(delegate.getClass())).toArray(new Class<?>[] {}),
                new LoginContextInvocationHandler<Object>(delegate, loginContext, interfacesToDelegate));
    }

    @Override
    public Object invoke(Object proxy, final Method method, final Object[] args) throws Throwable {
        try {
            return Subject.doAs(loginContext.getSubject(), new PrivilegedExceptionAction<Object>() {

                @Override
                public Object run() throws Exception {
                    Object result = method.invoke(delegate, args);
                    if (result != null) {
                        for (Class<?> iface : result.getClass().getInterfaces()) {
                            if (interfacesToDelegate.contains(iface)) {
                                result = forObject(result, loginContext, interfacesToDelegate);
                                break;
                            }
                        }
                    }
                    return result;
                }
            });
        } catch (PrivilegedActionException e) {
            if (e.getCause() instanceof InvocationTargetException) {
                throw ((InvocationTargetException) e.getCause()).getCause();
            }
            throw e;
        }
    }
}