/*
* @(#)TimeInRangeFunction.java
*
* Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved.
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* modification, are permitted provided that the following conditions are met:
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*
* This software is provided "AS IS," without a warranty of any kind. ALL
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package com.sun.xacml.cond;
import java.util.List;
import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.attr.AttributeValue;
import com.sun.xacml.attr.BooleanAttribute;
import com.sun.xacml.attr.TimeAttribute;
/**
* This class implements the time-in-range function, which takes three time values and returns true
* if the first value falls between the second and the third value. This function was introduced in
* XACML 2.0.
* <p>
* Note that this function allows any time ranges less than 24 hours. In other words, it is not
* bound by normal day boundries (midnight GMT), but by the minimum time in the range. This means
* that ranges like 9am-5pm are supported, as are ranges like 5pm-9am.
*
* @since 2.0
* @author seth proctor
*/
public class TimeInRangeFunction extends FunctionBase {
/**
* The identifier for this function
*/
public static final String NAME = FUNCTION_NS_2 + "time-in-range";
/**
* The number of milliseconds in a minute
*/
public static final long MILLIS_PER_MINUTE = 1000 * 60;
/**
* The number of milliseconds in a day
*/
public static final long MILLIS_PER_DAY = MILLIS_PER_MINUTE * 60 * 24;
/**
* Default constructor.
*/
public TimeInRangeFunction() {
super(NAME, 0, TimeAttribute.identifier, false, 3, BooleanAttribute.identifier, false);
}
/**
* Evaluates the time-in-range function, which takes three <code>TimeAttribute</code> values.
* This function return true if the first value falls between the second and third values (ie.,
* on or after the second time and on or before the third time). If no time zone is specified
* for the second and/or third time value, then the timezone from the first time value is used.
* This lets you say time-in-range(current-time, 9am, 5pm) and always have the evaluation happen
* in your current-time timezone.
*
* @param inputs
* a <code>List</code> of <code>Evaluatable</code> objects representing the arguments
* passed to the function
* @param context
* the respresentation of the request
*
* @return an <code>EvaluationResult</code> containing true or false
*/
public EvaluationResult evaluate(List<? extends Expression> inputs, EvaluationCtx context) {
AttributeValue[] argValues = new AttributeValue[inputs.size()];
EvaluationResult result = evalArgs(inputs, context, argValues);
// check if any errors occured while resolving the inputs
if (result != null)
return result;
// get the three time values
TimeAttribute attr = (TimeAttribute) (argValues[0]);
long middleTime = attr.getMilliseconds();
long minTime = resolveTime(attr, (TimeAttribute) (argValues[1]));
long maxTime = resolveTime(attr, (TimeAttribute) (argValues[2]));
// first off, if the min and max are the same, then this can only
// be true is the middle is also the same value
if (minTime == maxTime)
return EvaluationResult.getInstance(middleTime == minTime);
// shift the minTime to 00:00:00 so we can do a normal comparison,
// taking care to shift in the correct direction (left if the
// maxTime is bigger, otherwise right), and making sure that we
// handle any wrapping values for the middle time (the maxTime will
// never wrap around 00:00:00 GMT as long as we're dealing with
// windows of less than 24 hours)
// the amount we're shifting
long shiftSpan;
// figure out the right direction and get the shift amount
if (minTime < maxTime)
shiftSpan = -minTime;
else
shiftSpan = MILLIS_PER_DAY - minTime;
// shift the maxTime and the middleTime
maxTime = maxTime + shiftSpan;
middleTime = handleWrap(middleTime + shiftSpan);
// we're in the range if the middle is now between 0 and maxTime
return EvaluationResult.getInstance((middleTime >= 0) && (middleTime <= maxTime));
}
/**
* Private helper method that is used to resolve the correct values for min and max. If an
* explicit timezone is provided for either, then that value gets used. Otherwise we need to
* pick the timezone the middle time is using, and move the other time into that timezone.
*/
private long resolveTime(TimeAttribute middleTime, TimeAttribute otherTime) {
long time = otherTime.getMilliseconds();
int tz = otherTime.getTimeZone();
// if there's no explicit timezone, then the otherTime needs to
// be shifted to the middleTime's timezone
if (tz == TimeAttribute.TZ_UNSPECIFIED) {
// the other time didn't specify a timezone, so we use the
// timezone specified in the middle time...
int middleTz = middleTime.getTimeZone();
// ...and we get the default timezone from the otherTime
tz = otherTime.getDefaultedTimeZone();
// if there was no specified timezone for the middleTime, use
// the default timezone for that too
if (middleTz == TimeAttribute.TZ_UNSPECIFIED)
middleTz = middleTime.getDefaultedTimeZone();
// use the timezone to offset the time value, if the two aren't
// already in the same timezone
if (middleTz != tz) {
time -= ((middleTz - tz) * MILLIS_PER_MINUTE);
time = handleWrap(time);
}
}
return time;
}
/**
* Private helper method that handles when a time value wraps no more than 24 hours either above
* 23:59:59 or below 00:00:00.
*/
private long handleWrap(long time) {
if (time < 0) {
// if it's negative, add one day
return time + MILLIS_PER_DAY;
}
if (time > MILLIS_PER_DAY) {
// if it's more than 24 hours, subtract one day
return time - MILLIS_PER_DAY;
}
return time;
}
}