GetBooleanAction.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 com.sun.jini.action;

import com.sun.jini.logging.Levels;
import com.sun.jini.logging.LogUtil;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.logging.Logger;
import net.jini.security.Security;

/**
 * A convenience class for retrieving the <code>boolean</code> value
 * of a system property as a privileged action.
 *
 * <p>An instance of this class can be used as the argument of {@link
 * AccessController#doPrivileged(PrivilegedAction)
 * AccessController.doPrivileged} or {@link
 * Security#doPrivileged(PrivilegedAction) Security.doPrivileged}.
 *
 * <p>The following code retrieves the boolean value of the system
 * property named <code>"prop"</code> as a privileged action:
 *
 * <pre>
 * boolean b = ((Boolean) Security.doPrivileged(
 *                 new GetBooleanAction("prop"))).booleanValue();
 * </pre>
 *
 * <p>If the protection domain of the immediate caller of
 * <code>doPrivileged</code> or the protection domain of this class
 * does not imply the permissions necessary for the operation, the
 * behavior is as if the system property is not defined.
 *
 * @author	Sun Microsystems, Inc.
 * 
 * @see		PrivilegedAction
 * @see		AccessController
 * @see		Security
 * @since 2.0
 **/
public class GetBooleanAction implements PrivilegedAction {

    private static final Logger logger =
	Logger.getLogger("com.sun.jini.action.GetBooleanAction");

    private final String theProp;

    /**
     * Constructor that takes the name of the system property whose
     * <code>boolean</code> value needs to be determined.
     *
     * @param	theProp the name of the system property
     **/
    public GetBooleanAction(String theProp) {
	this.theProp = theProp;
    }

    /**
     * Determines the <code>boolean</code> value of the system
     * property whose name was specified in the constructor.  The
     * value is returned in a <code>Boolean</code> object.
     *
     * <p>If the system property is defined to equal the string
     * <code>"true"</code> (case insensitive), then this method
     * returns a <code>Boolean</code> with the value
     * <code>true</code>.  Otherwise, this method returns a
     * <code>Boolean</code> with the value <code>false</code>.
     *
     * @return	a <code>Boolean</code> representing the value of
     * the system property
     **/
    public Object run() {
	try {
	    return Boolean.getBoolean(theProp) ? Boolean.TRUE : Boolean.FALSE;
	} catch (SecurityException e) {
	    if (logger.isLoggable(Levels.HANDLED)) {
		LogUtil.logThrow(logger, Levels.HANDLED,
		    GetBooleanAction.class, "run",
		    "security exception reading \"{0}\", returning false",
		    new Object[] { theProp }, e);
	    }
	    return Boolean.FALSE;
	}
    }
}