/*
 * @(#)FunctionCluster.java
 *
 * Copyright 2004 Sun Microsystems, Inc. All Rights Reserved.
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 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
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package com.sun.xacml.cond.cluster;

import java.util.Set;


/**
 * Interface used by classes that support more than one function. It's a
 * common design model to have a single class support more than one XACML
 * function. In those cases, you should provide a proxy that implements
 * <code>FunctionCluster</code> in addition to the <code>Function</code>.
 * This is particularly important for the run-time configuration system,
 * which uses this interface to create "clusters" of functions and therefore
 * can use a smaller configuration file.
 *
 * @since 1.2
 * @author Seth Proctor
 */
public interface FunctionCluster
{

    /**
     * Returns a single instance of each of the functions supported by
     * some class. The <code>Set</code> must contain instances of
     * <code>Function</code>, and it must be both non-null and non-empty.
     * It may contain only a single <code>Function</code>.
     * <p>
     * Note that this is only used to return concrete <code>Function</code>s.
     * It may not be used to report abstract functions.
     *
     * @return the functions supported by this class
     */
    public Set getSupportedFunctions();

}