defaultvalidityperiodbehaviour.java

一个完整的XACML工程,学习XACML技术的好例子!

/*
* Copyright (c) 2000-2005, University of Salford
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this 
* list of conditions and the following disclaimer.
* 
* Redistributions in binary form must reproduce the above copyright notice, 
* this list of conditions and the following disclaimer in the documentation 
* and/or other materials provided with the distribution. 
*
* Neither the name of the University of Salford nor the names of its 
* contributors may be used to endorse or promote products derived from this 
* software without specific prior written permission. 
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
* POSSIBILITY OF SUCH DAMAGE.
*/

package issrg.pba.rbac;

/**
 * This class implements the default behaviour of the ValidityPeriod when 
 * computing intersections of two periods.
 */

public abstract class DefaultValidityPeriodBehaviour extends SubsetCredentials implements ValidityPeriod {

  protected DefaultValidityPeriodBehaviour() {
  }

  /**
   * This method checks if this ValidityPeriod contains the given Credentials.
   * It makes sense to pass only ValidityPeriod to this method, but it can
   * handle other Credentials, too. Bascially, it checks that the notBefore
   * of the given ValidityPeriod is not earlier than notBefore of this 
   * ValidityPeriod, and that notAfter is not later than notAfter of this
   * ValidityPeriod. If the given Credentials is not a ValidityPeriod, the 
   * contains method of the superclass is called.
   *
   * @param c - the Credentials object that must be contained in this 
   *   ValidityPeriod
   * @return true, if the given Credentials is a ValidityPeriod and is fully
   *   contained in this ValidityPeriod; if it is not a ValidityPeriod, the 
   *   behaviour is defined by the superclass (calls the contains method of the 
   *   superclass); otherwise it is false.
   */
  public boolean contains(issrg.pba.Credentials c){
    //System.out.println("\n\n\t******** CONTAINS ******\n\t"+this+"\n\t"+c); //***********

    boolean b;

    if (c==null){
      b=false;
    }else if (!(c instanceof ValidityPeriod)){
      b=super.contains(c);
    }else if (c instanceof AdjustedValidityPeriod){
      b=contains(((AdjustedValidityPeriod)c).adjust(this));
    }else{

      ValidityPeriod vp = (ValidityPeriod)c;
      java.util.Date time = getNotBefore();
      boolean before = time==null || (vp.getNotBefore()!=null && !time.after(vp.getNotBefore())); // this is before vp, if this starts at -oo, or if vp is the same or after time (vp doesn't start at -oo, in particular)
      time = getNotAfter();
      boolean after = time==null || (vp.getNotAfter()!=null && !time.before(vp.getNotAfter())); // this is after vp, if this ends at +oo, or if vp is the same or before time (vp doesn't end at +oo, in particular)

      b = before && after;
    }

    //System.out.println("\t"+b); //**************
    return b;
  }

  /**
   * This method computes an intersection of this ValidityPeriod with the
   * given Credentials. It makes sense only to intersect the ValidityPeriod with
   * other ValidityPeriods, but other Credentials are supported. Basically, it
   * ensures that the result of intersection provides a stricter ValidityPeriod
   * than this ValidityPeriod and the provided ValidityPeriod.
   *
   * @param c - the ValidityPeriod to intersect with; if it is not a 
   *   ValidityPeriod, the result is determined by the inherited intersection
   *   method
   * @return the ValidityPeriod that is the intersection of this and the given
   *   ValidityPeriod
   */
  public issrg.pba.Credentials intersection(issrg.pba.Credentials c){
    //System.out.println("\n\t*** INTERSECTION ***\n\t"+this+"\n\t"+c); //*****

    if (c==null){
      //return null;
    }else if (!(c instanceof ValidityPeriod)){
      c=super.intersection(c);
    }else if (c instanceof AdjustedValidityPeriod){
      c=((AdjustedValidityPeriod)c).intersection(this);  // if this is AdjustedValidityPeriod, it will never get here
    }else c=new IntersectionValidityPeriod(this, (ValidityPeriod)c);

    //System.out.println("\n\tresult: "+c); //*****
    return c;
  }
}