adjustedperiodcollection.java

一个完整的XACML工程,学习XACML技术的好例子!

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package issrg.pba.rbac;

/**
 * This is a collection of periods that are applied together. This is an 
 * advanced implementation of intersection. Normally the 
 * IntersectionValidityPeriod produces the validity period that is just a set of
 * the latest notBefore and the earliest notAfter, which is good for 
 * constraining. However, Age and Min cannot be implemented this way, because
 * if the ValidityPeriod exceeds one of the margins, it is fully invalid, and
 * not just constrained.
 *
 * @author A.Otenko
 */

public class AdjustedPeriodCollection extends AdjustedValidityPeriod {

  private ValidityPeriod vp1;
  private ValidityPeriod vp2;

  protected AdjustedPeriodCollection(){
    super();
  }

  /**
   * This constructor builds a AdjustedPeriodCollection of two ValidityPeriods.
   * More ValidityPeriods can be added to the collection by chaining multiple
   * AdjustedPeriodCollection as a binary tree. Both ValidityPeriods are treated
   * equally.
   *
   * @param vp1 - one ValidityPeriod
   * @param vp2 - another ValidityPeriod
   */
  public AdjustedPeriodCollection(ValidityPeriod vp1, ValidityPeriod vp2) {
    super();

    this.vp1=vp1;
    this.vp2=vp2;
  }

  /**
   * This method returns an adjusted ValidityPeriod, where the collection of
   * ValidityPeriods provided at construction time is adjusted against the 
   * given ValidityPeriod.
   *
   * @param vp - the ValidityPeriod to adjust against
   */
  public ValidityPeriod adjust(ValidityPeriod vp){
    if (vp1!=null){
      if (vp1 instanceof AdjustedValidityPeriod){
        vp = ((AdjustedValidityPeriod)vp1).adjust(vp);
      }else{
        vp = new IntersectionValidityPeriod(vp1, vp);
      }
    }

    if (vp2!=null){
      if (vp2 instanceof AdjustedValidityPeriod){
        vp = ((AdjustedValidityPeriod)vp2).adjust(vp);
      }else{
        vp = new IntersectionValidityPeriod(vp2, vp);
      }
    }

    return vp;
  }

  public String toString(){
    return "{rule "+vp1+" && "+vp2+"}";
  }
}