/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE
* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at
* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
* add the following below this CDDL HEADER, with the fields enclosed
* by brackets "[]" replaced with your own identifying information:
* Portions Copyright [yyyy] [name of copyright owner]
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*
*
* Copyright 2006-2008 Sun Microsystems, Inc.
*/
package org.opends.server.types;
import java.util.HashSet;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* An iterable read-only view of of a set of attribute values returned
* from methods such as
* {@link org.opends.server.types.Entry#getAttribute(AttributeType)}.
* <p>
* Using instances of this class it is possible to filter out
* attribute values which do not have the correct options set. This is
* achieved without having to duplicate the set of attributes.
*/
@org.opends.server.types.PublicAPI(
stability=org.opends.server.types.StabilityLevel.VOLATILE,
mayInstantiate=false,
mayExtend=false,
mayInvoke=true)
public final class AttributeValueIterable implements
Iterable<AttributeValue> {
// The set of attributes having the same type and options.
private Iterable<Attribute> attributes;
// The set of options which all values must contain.
private HashSet<String> options;
/**
* Create a new attribute value iterable object.
*
* @param attributes The set of attributes having the same type.
* Can be {@code null}.
*/
public AttributeValueIterable(Iterable<Attribute> attributes) {
this(attributes, null);
}
/**
* Create a new attribute value iterable object.
*
* @param attributes The set of attributes having the same type.
* Can be {@code null}.
* @param options The set of options which all values must
* contain, or {@code null} if no options are
* required.
*/
public AttributeValueIterable(Iterable<Attribute> attributes,
HashSet<String> options) {
this.attributes = attributes;
this.options = options;
}
/**
* Retrieves an iterator that can be used to cursor through the set
* of attribute values.
*
* @return An iterator that can be used to cursor through the set
* of attribute values.
*/
public Iterator<AttributeValue> iterator() {
return new AttributeValueIterator();
}
/**
* Private iterator implementation.
*/
private class AttributeValueIterator
implements Iterator<AttributeValue> {
// Flag indicating whether iteration can proceed.
private boolean hasNext;
// The current attribute iterator.
private Iterator<Attribute> attributeIterator;
// The current value iterator.
private Iterator<AttributeValue> valueIterator;
/**
* Create a new attribute value iterator over the attribute set.
*/
private AttributeValueIterator() {
this.valueIterator = null;
if (attributes != null) {
this.attributeIterator = attributes.iterator();
this.hasNext = skipNonMatchingAttributes();
} else {
this.attributeIterator = null;
this.hasNext = false;
}
}
/**
* Indicates whether there are more attribute values to return.
*
* @return {@code true} if there are more attribute values to
* return, or {@code false} if not.
*/
public boolean hasNext() {
return hasNext;
}
/**
* Retrieves the next attribute value in the set.
*
* @return The next attribute value in the set.
*
* @throws NoSuchElementException If there are no more values to
* return.
*/
public AttributeValue next()
throws NoSuchElementException
{
if (hasNext == false) {
throw new NoSuchElementException();
}
AttributeValue value = valueIterator.next();
// We've reached the end of this array list, so skip to the next
// non-empty one.
if (valueIterator.hasNext() == false) {
hasNext = skipNonMatchingAttributes();
}
return value;
}
/**
* Removes the last attribute value retrieved from the set. Note
* that this operation is not supported and will always cause an
* {@code UnsupportedOperationException} to be thrown.
*
* @throws UnsupportedOperationException If the last value
* cannot be removed.
*/
public void remove()
throws UnsupportedOperationException
{
throw new UnsupportedOperationException();
}
/**
* Skip past any empty attributes or attributes that do not have
* the correct set of options until we find one that contains some
* values.
*
* @return {@code true} if iteration can continue, or
* {@code false} if not.
*/
private boolean skipNonMatchingAttributes() {
while (attributeIterator.hasNext()) {
Attribute attribute = attributeIterator.next();
if (attribute.hasAllOptions(options)) {
valueIterator = attribute.iterator();
if (valueIterator.hasNext()) {
return true;
}
}
}
return false;
}
}
}