/*
* @(#)BagAttribute.java
*
* Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistribution 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 Sun Microsystems, Inc. or the names of contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
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*/
package com.sun.xacml.attr;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* Represents a bag used in the XACML spec as return values from functions and designators/selectors
* that provide more than one value. All values in the bag are of the same type, and the bag may be
* empty. The bag is immutable, although its contents may not be.
* <p>
* NOTE: This is the one standard attribute type that can't be created from the factory, since you
* can't have this in an XML block (it is used only in return values & dynamic inputs). I think this
* is right, but we may need to add some functionality to let this go into the factory.
*
* @since 1.0
* @author Seth Proctor
* @author Steve Hanna
*
* Adding generic type support by Christian Mueller (geotools)
*/
public class BagAttribute extends AttributeValue {
// The Collection of AttributeValues that this object encapsulates
private Collection<AttributeValue> bag;
/**
* Creates a new <code>BagAttribute</code> that represents the <code>Collection</code> of
* <code>AttributeValue</code>s supplied. If the set is null or empty, then the new bag is
* empty.
*
* @param type
* the data type of all the attributes in the set
* @param bag
* a <code>Collection</code> of <code>AttributeValue</code>s
*/
public BagAttribute(URI type, Collection<AttributeValue> bag) {
super(type);
if (type == null)
throw new IllegalArgumentException("Bags require a non-null " + "type be provided");
// see if the bag is empty/null
if ((bag == null) || (bag.size() == 0)) {
// empty bag
this.bag = new ArrayList<AttributeValue>();
} else {
// go through the collection to make sure it's a valid bag
Iterator<AttributeValue> it = bag.iterator();
while (it.hasNext()) {
AttributeValue attr = it.next();
// a bag cannot contain other bags, so make sure that each
// value isn't actually another bag
if (attr.isBag())
throw new IllegalArgumentException("bags cannot contain " + "other bags");
// make sure that they're all the same type
if (!type.equals(attr.getType()))
throw new IllegalArgumentException("Bag items must all be of "
+ "the same type");
}
// if we get here, then they're all the same type
this.bag = bag;
}
}
/**
* Overrides the default method to always return true.
*
* @return a value of true
*/
public boolean isBag() {
return true;
}
/**
* Convenience function that returns a bag with no elements
*
* @param type
* the types contained in the bag
*
* @return a new empty bag
*/
public static BagAttribute createEmptyBag(URI type) {
return new BagAttribute(type, null);
}
/**
* A convenience function that returns whether or not the bag is empty (ie, whether or not the
* size of the bag is zero)
*
* @return whether or not the bag is empty
*/
public boolean isEmpty() {
return (bag.size() == 0);
}
/**
* Returns the number of elements in this bag
*
* @return the number of elements in this bag
*/
public int size() {
return bag.size();
}
/**
* Returns true if this set contains the specified value. More formally, returns true if and
* only if this bag contains a value v such that (value==null ? v==null : value.equals(v)). Note
* that this will only work correctly if the <code>AttributeValue</code> has overridden the
* <code>equals</code> method.
*
* @param value
* the value to look for
*
* @return true if the value is in the bag
*/
public boolean contains(AttributeValue value) {
return bag.contains(value);
}
/**
* Returns true if this bag contains all of the values of the specified bag. Note that this will
* only work correctly if the <code>AttributeValue</code> type contained in the bag has
* overridden the <code>equals</code> method.
*
* @param bag
* the bag to compare
*
* @return true if the input is a subset of this bag
*/
public boolean containsAll(BagAttribute bag) {
return this.bag.containsAll(bag.bag);
}
/**
* Returns an iterator over te
*/
public Iterator<AttributeValue> iterator() {
return new ImmutableIterator<AttributeValue>(bag.iterator());
}
/**
* This is a version of Iterator that overrides the <code>remove</code> method so that items
* can't be taken out of the bag.
*/
private class ImmutableIterator<E> implements Iterator<E> {
// the iterator we're wrapping
private Iterator<E> iterator;
/**
* Create a new ImmutableIterator
*/
public ImmutableIterator(Iterator<E> iterator) {
this.iterator = iterator;
}
/**
* Standard hasNext method
*/
public boolean hasNext() {
return iterator.hasNext();
}
/**
* Standard next method
*/
public E next() throws NoSuchElementException {
return iterator.next();
}
/**
* Makes sure that no one can remove any elements from the bag
*/
public void remove() throws UnsupportedOperationException {
throw new UnsupportedOperationException();
}
}
/**
* Not Specified TODO
*
*/
public String encode() {
StringBuffer buff = new StringBuffer();
for (AttributeValue value : bag)
buff.append(value.encode()).append(",");
if (buff.length() > 1)
buff.setLength(buff.length() - 1);
return buff.toString();
// throw new UnsupportedOperationException("Bags cannot be encoded");
}
@Override
public String encodeWithTags(boolean includeType) {
StringBuffer buff = new StringBuffer();
for (AttributeValue value : bag)
buff.append(value.encodeWithTags(includeType));
return buff.toString();
}
}