openaz-xacml-pdp/src/main/java/org/apache/openaz/xacml/pdp/policy/FunctionDefinition.java

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 *  Licensed to the Apache Software Foundation (ASF) under one
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 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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/*
 *                        AT&T - PROPRIETARY
 *          THIS FILE CONTAINS PROPRIETARY INFORMATION OF
 *        AT&T AND IS NOT TO BE DISCLOSED OR USED EXCEPT IN
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package org.apache.openaz.xacml.pdp.policy;

import java.util.List;

import org.apache.openaz.xacml.api.Identifier;
import org.apache.openaz.xacml.pdp.eval.EvaluationContext;

/**
 * FunctionDefinition is the interface that objects representing XACML functions found in Match and Apply
 * elements in Policies, PolicySets and Rules.
 */
public interface FunctionDefinition {
    /**
     * Gets the {@link org.apache.openaz.xacml.api.Identifier} for this <code>FunctionDefinition</code>.
     *
     * @return the <code>Identifier</code> for this <code>FunctionDefinition</code>.
     */
    Identifier getId();

    /**
     * Returns the <code>Identifier</code> for the data type returned by this function if
     * <code>returnsBag()</code> is false or if this <code>FunctionDefinition</code> returns a bag containing
     * a single data type. Otherwise it returns null.
     *
     * @return the <code>Identifier</code> for the XACML data type this <code>FunctionDefinition</code>
     *         returns
     */
    Identifier getDataTypeId();

    /**
     * Determines if this <code>FunctionDefinition</code> returns a bag of values or a single value.
     *
     * @return true if this <code>FunctionDefinition</code> returns a bag, else false
     */
    boolean returnsBag();

    /**
     * Evaluates this <code>FunctionDefinition</code> on the given <code>List</code> of
     * {@link FunctionArgument}s.
     *
     * @param evaluationContext the {@link org.apache.openaz.xacml.pdp.eval.EvaluationContext} to use in the
     *            evaluation
     * @param arguments the <code>List</code> of <code>FunctionArgument</code>s for the evaluation
     * @return an {@link ExpressionResult} with the results of the call
     */
    ExpressionResult evaluate(EvaluationContext evaluationContext, List<FunctionArgument> arguments);
}