Source code: com/sun/xacml/cond/AddFunction.java
1
2 /*
3 * @(#)AddFunction.java
4 *
5 * Copyright 2003-2004 Sun Microsystems, Inc. All Rights Reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistribution of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistribution in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * Neither the name of Sun Microsystems, Inc. or the names of contributors may
18 * be used to endorse or promote products derived from this software without
19 * specific prior written permission.
20 *
21 * This software is provided "AS IS," without a warranty of any kind. ALL
22 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
23 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
24 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
25 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
26 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
27 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
28 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
29 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
30 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
31 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
32 *
33 * You acknowledge that this software is not designed or intended for use in
34 * the design, construction, operation or maintenance of any nuclear facility.
35 */
36
37 package com.sun.xacml.cond;
38
39 import com.sun.xacml.EvaluationCtx;
40
41 import com.sun.xacml.attr.AttributeValue;
42 import com.sun.xacml.attr.DoubleAttribute;
43 import com.sun.xacml.attr.IntegerAttribute;
44
45 import java.util.HashSet;
46 import java.util.List;
47 import java.util.Set;
48
49
50 /**
51 * A class that implements all the *-add functions. It takes two or more
52 * operands of the appropriate type and returns the sum of the operands.
53 * If any of the operands is indeterminate, an indeterminate result is
54 * returned.
55 *
56 * @since 1.0
57 * @author Steve Hanna
58 * @author Seth Proctor
59 */
60 public class AddFunction extends FunctionBase
61 {
62
63 /**
64 * Standard identifier for the integer-add function.
65 */
66 public static final String NAME_INTEGER_ADD =
67 FUNCTION_NS + "integer-add";
68
69 /**
70 * Standard identifier for the double-add function.
71 */
72 public static final String NAME_DOUBLE_ADD =
73 FUNCTION_NS + "double-add";
74
75 // inernal identifiers for each of the supported functions
76 private static final int ID_INTEGER_ADD = 0;
77 private static final int ID_DOUBLE_ADD = 1;
78
79 /**
80 * Creates a new <code>AddFunction</code> object.
81 *
82 * @param functionName the standard XACML name of the function to be
83 * handled by this object, including the full namespace
84 *
85 * @throws IllegalArgumentException if the function is unknown
86 */
87 public AddFunction(String functionName) {
88 super(functionName, getId(functionName), getArgumentType(functionName),
89 false, -1, 2, getArgumentType(functionName), false);
90 }
91
92 /**
93 * Private helper that returns the internal identifier used for the
94 * given standard function.
95 */
96 private static int getId(String functionName) {
97 if (functionName.equals(NAME_INTEGER_ADD))
98 return ID_INTEGER_ADD;
99 else if (functionName.equals(NAME_DOUBLE_ADD))
100 return ID_DOUBLE_ADD;
101 else
102 throw new IllegalArgumentException("unknown add function " +
103 functionName);
104 }
105
106 /**
107 * Private helper that returns the type used for the given standard
108 * function. Note that this doesn't check on the return value since the
109 * method always is called after getId, so we assume that the function
110 * is present.
111 */
112 private static String getArgumentType(String functionName) {
113 if (functionName.equals(NAME_INTEGER_ADD))
114 return IntegerAttribute.identifier;
115 else
116 return DoubleAttribute.identifier;
117 }
118
119 /**
120 * Returns a <code>Set</code> containing all the function identifiers
121 * supported by this class.
122 *
123 * @return a <code>Set</code> of <code>String</code>s
124 */
125 public static Set getSupportedIdentifiers() {
126 Set set = new HashSet();
127
128 set.add(NAME_INTEGER_ADD);
129 set.add(NAME_DOUBLE_ADD);
130
131 return set;
132 }
133
134 /**
135 * Evaluate the function, using the specified parameters.
136 *
137 * @param inputs a <code>List</code> of <code>Evaluatable</code>
138 * objects representing the arguments passed to the function
139 * @param context an <code>EvaluationCtx</code> so that the
140 * <code>Evaluatable</code> objects can be evaluated
141 * @return an <code>EvaluationResult</code> representing the
142 * function's result
143 */
144 public EvaluationResult evaluate(List inputs, EvaluationCtx context) {
145
146 // Evaluate the arguments
147 AttributeValue [] argValues = new AttributeValue[inputs.size()];
148 EvaluationResult result = evalArgs(inputs, context, argValues);
149 if (result != null)
150 return result;
151
152 // Now that we have real values, perform the add operation
153 switch (getFunctionId()) {
154 case ID_INTEGER_ADD: {
155 long sum = 0;
156 for (int index = 0; index < argValues.length; index++) {
157 long arg = ((IntegerAttribute) argValues[index]).getValue();
158 sum += arg;
159 }
160
161 result = new EvaluationResult(new IntegerAttribute(sum));
162 break;
163 }
164 case ID_DOUBLE_ADD: {
165 double sum = 0;
166 for (int index = 0; index < argValues.length; index++) {
167 double arg =
168 ((DoubleAttribute) argValues[index]).getValue();
169 sum = sum + arg;
170 }
171
172 // Make it round half even, not round nearest
173 double lower = Math.floor(sum);
174 double higher = lower + 1;
175 if ((sum - lower) == (higher - sum)) {
176 if ((lower % 2) == 0)
177 sum = lower;
178 else
179 sum = higher;
180 }
181
182 result = new EvaluationResult(new DoubleAttribute(sum));
183 break;
184 }
185 }
186
187 return result;
188 }
189
190 }