42 lines
1.5 KiB
Plaintext
42 lines
1.5 KiB
Plaintext
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When using <code>Math.min()</code> and <code>Math.max()</code> together for bounds checking, it's important to feed the right operands to each method. <code>Math.min()</code> should be used with the *upper* end of the range being checked, and <code>Math.max()</code> should be used with the *lower* end of the range. Get it backwards, and the result will always be the same end of the range.
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== Noncompliant Code Example
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----
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private static final int UPPER = 20;
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private static final int LOWER = 0;
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public int doRangeCheck(int num) { // Let's say num = 12
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int result = Math.min(LOWER, num); // result = 0
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return Math.max(UPPER, result); // Noncompliant; result is now 20: even though 12 was in the range
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}
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----
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== Compliant Solution
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Swapping method <code>min()</code> and <code>max()</code> invocations without changing parameters.
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----
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private static final int UPPER = 20;
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private static final int LOWER = 0;
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public int doRangeCheck(int num) { // Let's say num = 12
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int result = Math.max(LOWER, num); // result = 12
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return Math.min(UPPER, result); // Compliant; result is still 12
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}
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----
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or swapping bounds <code>UPPER</code> and <code>LOWER</code> used as parameters without changing the invoked methods.
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----
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private static final int UPPER = 20;
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private static final int LOWER = 0;
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public int doRangeCheck(int num) { // Let's say num = 12
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int result = Math.min(UPPER, num); // result = 12
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return Math.max(LOWER, result); // Compliant; result is still 12
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}
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----
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