apply.java

sunxacml源码

/*
 * @(#)Apply.java
 *
 * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *   2. Redistribution in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
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 *
 * You acknowledge that this software is not designed or intended for use in
 * the design, construction, operation or maintenance of any nuclear facility.
 */

package com.sun.xacml.cond;

import com.sun.xacml.EvaluationCtx;
import com.sun.xacml.Indenter;
import com.sun.xacml.ParsingException;
import com.sun.xacml.PolicyMetaData;

import com.sun.xacml.attr.AttributeFactory;

import java.io.OutputStream;
import java.io.PrintStream;

import java.net.URI;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


/**
 * Represents the XACML ApplyType and ConditionType XML types.
 * <p>
 * Note well: as of 2.0, there is no longer a notion of a separate higher-
 * order bag function. Instead, if needed, it is supplied as one of the
 * <code>Expression</code>s in the parameter list. As such, when this
 * <code>Apply</code> is evaluated, it no longer pre-evaluates all the
 * parameters if a bag function is used. It is now up to the implementor
 * of a higher-order function to do this.
 * <p>
 * Also, as of 2.0, the <code>Apply</code> is no longer used to represent
 * a Condition, since the XACML 2.0 specification changed how Condition
 * works. Instead, there is now a <code>Condition</code> class that
 * represents both 1.x and 2.0 style Conditions.
 *
 * @since 1.0
 * @author Seth Proctor
 */
public class Apply implements Evaluatable
{

    // the function used to evaluate the contents of the apply
    private Function function;

    // the paramaters to the function...ie, the contents of the apply
    private List xprs;

    /**
     * Constructs an <code>Apply</code> instance.
     * 
     * @param function the <code>Function</code> to use in evaluating the
     *                 elements in the apply
     * @param xprs the contents of the apply which will be the parameters
     *              to the function, each of which is an
     *              <code>Expression</code>
     *
     * @throws IllegalArgumentException if the input expressions don't
     *                                  match the signature of the function
     */
    public Apply(Function function, List xprs)
        throws IllegalArgumentException
    {
        // check that the given inputs work for the function
        function.checkInputs(xprs);

        // if everything checks out, then store the inputs
        this.function = function;
        this.xprs = Collections.unmodifiableList(new ArrayList(xprs));
    }

    /**
     * Constructs an <code>Apply</code> instance.
     * 
     * @deprecated As of 2.0 <code>Apply</code> is no longer used for
     *             Conditions, so the <code>isCondition</code> parameter
     *             is no longer needed. You should now use the 2 parameter
     *             constructor. This constructor will be removed in a
     *             future release.
     *
     * @param function the <code>Function</code> to use in evaluating the
     *                 elements in the apply
     * @param xprs the contents of the apply which will be the parameters
     *              to the function, each of which is an
     *              <code>Expression</code>
     * @param isCondition as of 2.0, this must always be false
     *
     * @throws IllegalArgumentException if the input expressions don't
     *                                  match the signature of the function or
     *                                  if <code>isCondition</code> is true
     */
    public Apply(Function function, List xprs, boolean isCondition)
        throws IllegalArgumentException
    {
        // make sure that no is using this constructor to create a Condition
        if (isCondition)
            throw new IllegalArgumentException("As of version 2.0 an Apply" +
                                               " may not represent a" +
                                               " Condition");

        // check that the given inputs work for the function
        function.checkInputs(xprs);

        // if everything checks out, then store the inputs
        this.function = function;
        this.xprs = Collections.unmodifiableList(new ArrayList(xprs));
    }

    /**
     * Returns an instance of an <code>Apply</code> based on the given DOM
     * root node. This will actually return a special kind of
     * <code>Apply</code>, namely an XML ConditionType, which is the root
     * of the condition logic in a RuleType. A ConditionType is the same
     * as an ApplyType except that it must use a FunctionId that returns
     * a boolean value.
     * <p>
     * Note that as of 2.0 there is a separate <code>Condition</code> class
     * used to support the different kinds of Conditions in XACML 1.x and
     * 2.0. As such, the system no longer treats a ConditionType as a
     * special kind of ApplyType. You may still use this method to get a
     * 1.x style ConditionType, but you will need to convert it into a
     * <code>Condition</code> to use it in evaluation. The preferred way
     * to create a Condition is now through the <code>getInstance</code>
     * method on <code>Condition</code>.
     * 
     * @param root the DOM root of a ConditionType XML type
     * @param xpathVersion the XPath version to use in any selectors or XPath
     *                     functions, or null if this is unspecified (ie, not
     *                     supplied in the defaults section of the policy)
     * @param manager <code>VariableManager</code> used to connect references
     *                and definitions while parsing
     *
     * @throws ParsingException if this is not a valid ConditionType
     */
    public static Apply getConditionInstance(Node root, String xpathVersion,
                                             VariableManager manager)
        throws ParsingException
    {
        return getInstance(root, FunctionFactory.getConditionInstance(),
                           new PolicyMetaData(
                                   PolicyMetaData.XACML_1_0_IDENTIFIER,
                                   xpathVersion),
                           manager);
    }

    /**
     * Returns an instance of an <code>Apply</code> based on the given DOM
     * root node. This will actually return a special kind of
     * <code>Apply</code>, namely an XML ConditionType, which is the root
     * of the condition logic in a RuleType. A ConditionType is the same
     * as an ApplyType except that it must use a FunctionId that returns
     * a boolean value.
     * 
     * @deprecated As of 2.0 you should avoid using this method, since it
     *             does not provide a <code>Condition</code> instance and
     *             does not handle XACML 2.0 policies correctly. If you need
     *             a similar method you can use the new version that
     *             accepts a <code>VariableManager</code>. This will return
     *             an <code>Apply</code> instance for XACML 1.x policies.
     *
     * @param root the DOM root of a ConditionType XML type
     * @param xpathVersion the XPath version to use in any selectors or XPath
     *                     functions, or null if this is unspecified (ie, not
     *                     supplied in the defaults section of the policy)
     *
     * @throws ParsingException if this is not a valid ConditionType
     */
    public static Apply getConditionInstance(Node root, String xpathVersion)