org.eclipse.sisu.wire.EntrySetAdapter Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2010-present Sonatype, Inc.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Stuart McCulloch (Sonatype, Inc.) - initial API and implementation
*******************************************************************************/
package org.eclipse.sisu.wire;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map.Entry;
import java.util.Set;
/**
* {@link Set} backed by an {@link Iterable} sequence of map entries.
*/
public final class EntrySetAdapter
extends AbstractSet
{
// ----------------------------------------------------------------------
// Implementation fields
// ----------------------------------------------------------------------
private final Iterable> iterable;
// ----------------------------------------------------------------------
// Constructors
// ----------------------------------------------------------------------
public EntrySetAdapter( final Iterable> iterable )
{
this.iterable = iterable;
}
// ----------------------------------------------------------------------
// Public methods
// ----------------------------------------------------------------------
@Override
public Iterator iterator()
{
return new ValueIterator( iterable );
}
@Override
public boolean isEmpty()
{
return false == iterator().hasNext();
}
@Override
public int size()
{
int size = 0;
for ( final Iterator i = iterable.iterator(); i.hasNext(); i.next() )
{
size++;
}
return size;
}
// ----------------------------------------------------------------------
// Implementation types
// ----------------------------------------------------------------------
/**
* Value {@link Iterator} backed by a Key:Value {@link Iterator}.
*/
private static final class ValueIterator
implements Iterator
{
// ----------------------------------------------------------------------
// Implementation fields
// ----------------------------------------------------------------------
private final Iterator> iterator;
// ----------------------------------------------------------------------
// Constructors
// ----------------------------------------------------------------------
ValueIterator( final Iterable> iterable )
{
this.iterator = iterable.iterator();
}
// ----------------------------------------------------------------------
// Public methods
// ----------------------------------------------------------------------
public boolean hasNext()
{
return iterator.hasNext();
}
public V next()
{
return iterator.next().getValue();
}
public void remove()
{
throw new UnsupportedOperationException();
}
}
}