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Oracle Coherence Community Edition
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.util;
import java.util.Collection;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* An unmodifiable Collection that provides access to many collections in the
* given order.
*
* @author hr 2014.02.19
* @since Coherence 12.1.2
*/
public class ChainedCollection
implements Collection
{
// ----- constructors ---------------------------------------------------
/**
* Construct a ChainedCollection with the provided Collection of Collection
* objects.
*
* @param col a Collection of Collection objects
*/
public ChainedCollection(Collection> col)
{
this(col.toArray(new Collection[col.size()]));
}
/**
* Construct a ChainedCollection with the provided array of Collection
* objects.
*
* @param acol an array of Collection objects
*/
public ChainedCollection(Collection...acol)
{
f_acol = acol;
}
// ----- Collection interface -------------------------------------------
@Override
public int size()
{
int cSize = 0;
for (Collection col : f_acol)
{
cSize += col.size();
}
return cSize;
}
@Override
public boolean isEmpty()
{
for (Collection col : f_acol)
{
if (!col.isEmpty())
{
return false;
}
}
return true;
}
@Override
public boolean contains(Object o)
{
for (Collection col : f_acol)
{
if (col.contains(o))
{
return true;
}
}
return false;
}
@Override
public boolean containsAll(Collection> col)
{
for (Object o : f_acol)
{
if (!contains(o))
{
return false;
}
}
return true;
}
@Override
public Iterator iterator()
{
return new Iterator()
{
@Override
public boolean hasNext()
{
Iterator iter = m_iter;
int iCol = m_iCol;
int cCol = f_acol.length;
while ((iter == null || !iter.hasNext()) && ++iCol < cCol)
{
iter = m_iter = f_acol[iCol].iterator();
m_iCol = iCol;
}
if (iCol >= cCol)
{
m_iter = null;
return false;
}
return true;
}
@Override
public E next()
{
if (hasNext())
{
return m_iter.next();
}
throw new NoSuchElementException();
}
@Override
public void remove()
{
if (m_iter == null)
{
throw new NoSuchElementException();
}
m_iter.remove();
}
Iterator m_iter;
int m_iCol = -1;
};
}
@Override
public Object[] toArray()
{
return toArray((Object[]) null);
}
@Override
public T[] toArray(T[] a)
{
int cSize = size();
if (a == null || cSize > a.length)
{
a = (T[]) new Object[cSize];
}
for (int i = 0, of = 0, cArray = f_acol.length; i < cArray; ++i)
{
Object[] aoCol = f_acol[i].toArray();
System.arraycopy(aoCol, 0, a, of, aoCol.length);
of += aoCol.length;
}
return a;
}
// ----- unsupported methods --------------------------------------------
@Override
public boolean add(E e)
{
throw new UnsupportedOperationException();
}
@Override
public boolean addAll(Collection extends E> c)
{
throw new UnsupportedOperationException();
}
@Override
public boolean remove(Object o)
{
throw new UnsupportedOperationException();
}
@Override
public boolean removeAll(Collection> c)
{
throw new UnsupportedOperationException();
}
@Override
public boolean retainAll(Collection> c)
{
throw new UnsupportedOperationException();
}
@Override
public void clear()
{
throw new UnsupportedOperationException();
}
// ----- data members ---------------------------------------------------
/**
* An array of Collections to enumerate.
*/
protected final Collection[] f_acol;
}