Source code: com/sun/xacml/cond/DivideFunction.java
1
2 /*
3 * @(#)DivideFunction.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 *-divide functions. It takes two
52 * operands of the appropriate type and returns the quotient of the
53 * operands. If either of the operands is indeterminate, an indeterminate
54 * result is returned.
55 *
56 * @since 1.0
57 * @author Steve Hanna
58 * @author Seth Proctor
59 */
60 public class DivideFunction extends FunctionBase
61 {
62
63 /**
64 * Standard identifier for the integer-divide function.
65 */
66 public static final String NAME_INTEGER_DIVIDE =
67 FUNCTION_NS + "integer-divide";
68
69 /**
70 * Standard identifier for the double-divide function.
71 */
72 public static final String NAME_DOUBLE_DIVIDE =
73 FUNCTION_NS + "double-divide";
74
75 // inernal identifiers for each of the supported functions
76 private static final int ID_INTEGER_DIVIDE = 0;
77 private static final int ID_DOUBLE_DIVIDE = 1;
78
79 /**
80 * Creates a new <code>DivideFunction</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 DivideFunction(String functionName) {
88 super(functionName, getId(functionName), getArgumentType(functionName),
89 false, 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_DIVIDE))
98 return ID_INTEGER_DIVIDE;
99 else if (functionName.equals(NAME_DOUBLE_DIVIDE))
100 return ID_DOUBLE_DIVIDE;
101 else
102 throw new IllegalArgumentException("unknown divide 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_DIVIDE))
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_DIVIDE);
129 set.add(NAME_DOUBLE_DIVIDE);
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 divide operation
153 // in the manner appropriate for the type of the arguments.
154 switch (getFunctionId()) {
155 case ID_INTEGER_DIVIDE: {
156 long dividend = ((IntegerAttribute) argValues[0]).getValue();
157 long divisor = ((IntegerAttribute) argValues[1]).getValue();
158
159 if (divisor == 0) {
160 result = makeProcessingError("divide by zero");
161 break;
162 }
163
164 long quotient = dividend / divisor;
165
166 result = new EvaluationResult(new IntegerAttribute(quotient));
167 break;
168 }
169 case ID_DOUBLE_DIVIDE: {
170 double dividend = ((DoubleAttribute) argValues[0]).getValue();
171 double divisor = ((DoubleAttribute) argValues[1]).getValue();
172
173 if (divisor == 0) {
174 result = makeProcessingError("divide by zero");
175 break;
176 }
177
178 double quotient = dividend / divisor;
179
180 result = new EvaluationResult(new DoubleAttribute(quotient));
181 break;
182 }
183 }
184
185 return result;
186 }
187 }