RingBuffer.java

package com.renomad.minum.utils;

import java.lang.reflect.Array;
import java.util.Iterator;
import java.util.List;
import java.util.NoSuchElementException;

/**
 * A minimalist implementation of a ring buffer
 * For use with web mechanisms like the multipart body processor
 * and the HTML processor.
 */
public class RingBuffer<T> implements Iterable<T>{

    /**
     * The size of the inner array supporting this class.  Also,
     * the most items our RingBuffer can contain.
     */
    private final int limit;

    /**
     * The last index of the array - just the limit minus 1.
     */
    private final int lastIndex;

    /**
     * An instance of the class for this generic collection, used to
     * help build data structures.
     */
    private final T[] innerArray;

    /**
     * Index of where we place the next item
     */
    private int nextIndex;

    /**
     * Build a {@link RingBuffer}
     * @param limit the maximum size of the buffer
     */
    public RingBuffer(int limit, Class<T> clazz) {
        this.limit = limit;
        this.lastIndex = limit - 1;
        @SuppressWarnings("unchecked")
        final T[] t = (T[]) Array.newInstance(clazz, limit);
        this.innerArray = t;
        this.nextIndex = 0;
    }

    /**
     * This will move the index forward and
     * wrap around at the end.
     */
    private int incrementIndex(int index) {
        if (index == lastIndex) {
            return 0;
        } else {
            return index + 1;
        }
    }

    public void add(T item) {
        innerArray[nextIndex] = item;
        nextIndex = incrementIndex(nextIndex);
    }

    public int getLimit() {
        return limit;
    }

    /**
     * Returns true if the data in the "myList" parameter is found
     * within the RingBuffer.
     */
    public boolean contains(List<T> myList) {
        if (myList == null || myList.isEmpty()) {
            throw new UtilsException("expected a valid non-empty list to search for in the RingBuffer");
        }
        int myListIndex = 0;
        int myListLength = myList.size();
        for (var value : this) {
            if (myList.get(myListIndex).equals(value)) {
                myListIndex += 1;
            } else {
                myListIndex = 0;
            }

            if (myListIndex == myListLength) {
                return true;
            }

        }
        return false;
    }

    /**
     * Returns true if the data in the "myList" parameter is found
     * within the RingBuffer at the index provided.
     */
    public boolean containsAt(List<T> myList, int index) {
        if (myList == null || myList.isEmpty()) {
            throw new UtilsException("expected a valid non-empty list to search for in the RingBuffer");
        }
        if (index > lastIndex || index < 0) {
            throw new UtilsException("expected an index greater than zero and less-than-or-equal to the last index of the buffer (the limit minus one)");
        }
        int i = 0;
        int myListIndex = 0;
        int myListLastIndex = myList.size() - 1;
        boolean comparing = false;
        var iterator = this.iterator();
        while (iterator.hasNext()) {
            var value = iterator.next();
            if (i == index) {
                comparing = true;
            }

            if (comparing) {
                if (! myList.get(myListIndex).equals(value)) {
                    return false;
                }
                if (myListIndex == myListLastIndex) {
                    return true;
                }
                myListIndex += 1;
            }

            i += 1;
        }
        return false;
    }

    @Override
    public Iterator<T> iterator() {
        return new Iterator<>() {

            /**
             * As we loop through the buffer, we have to use a similar
             * technique to the "nextIndex" - wrapping around when we
             * hit the end
             */
            int iteratorIndex = nextIndex;
            /**
             * We'll count as we read values, stopping when we've read every slot.
             */
            int count = 0;

            @Override
            public boolean hasNext() {
                return count < limit;
            }

            @Override
            public T next() {
                if (!hasNext()) {
                    throw new NoSuchElementException();
                }
                var result = innerArray[iteratorIndex];
                iteratorIndex = incrementIndex(iteratorIndex);
                count += 1;
                return result;
            }
        };
    }

    /**
     * Returns the value at the slot pointed to by the "nextIndex".  Note that
     * this will be null at first while the array starts to get filled.
     */
    public T atNextIndex() {
        return innerArray[nextIndex];
    }

}































Active mutators

CONDITIONALS_BOUNDARY
EMPTY_RETURNS
FALSE_RETURNS
INCREMENTS
INVERT_NEGS
MATH
NEGATE_CONDITIONALS
NULL_RETURNS
PRIMITIVE_RETURNS
TRUE_RETURNS
VOID_METHOD_CALLS

Tests examined

com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) (35 ms)
com.renomad.minum.utils.RingBufferTests (31 ms)
com.renomad.minum.web.BoundaryBugTest (30 ms)
com.renomad.minum.htmlparsing.HtmlParseNodeTests (45 ms)
com.renomad.minum.web.BodyProcessorTests (94 ms)
com.renomad.minum.web.RequestTests (186 ms)
com.renomad.minum.web.WebTests (698 ms)
com.renomad.minum.htmlparsing.HtmlParserTests (1173 ms)
com.renomad.minum.FunctionalTests.testEndToEnd_Functional(com.renomad.minum.FunctionalTests) (2259 ms)

Report generated by PIT 1.17.0

1		package com.renomad.minum.utils;
2
3		import java.lang.reflect.Array;
4		import java.util.Iterator;
5		import java.util.List;
6		import java.util.NoSuchElementException;
7
8		/**
9		* A minimalist implementation of a ring buffer
10		* For use with web mechanisms like the multipart body processor
11		* and the HTML processor.
12		*/
13		public class RingBuffer<T> implements Iterable<T>{
14
15		/**
16		* The size of the inner array supporting this class. Also,
17		* the most items our RingBuffer can contain.
18		*/
19		private final int limit;
20
21		/**
22		* The last index of the array - just the limit minus 1.
23		*/
24		private final int lastIndex;
25
26		/**
27		* An instance of the class for this generic collection, used to
28		* help build data structures.
29		*/
30		private final T[] innerArray;
31
32		/**
33		* Index of where we place the next item
34		*/
35		private int nextIndex;
36
37		/**
38		* Build a {@link RingBuffer}
39		* @param limit the maximum size of the buffer
40		*/
41		public RingBuffer(int limit, Class<T> clazz) {
42		this.limit = limit;
43	1 1. <init> : Replaced integer subtraction with addition → KILLED	this.lastIndex = limit - 1;
44		@SuppressWarnings("unchecked")
45		final T[] t = (T[]) Array.newInstance(clazz, limit);
46		this.innerArray = t;
47		this.nextIndex = 0;
48		}
49
50		/**
51		* This will move the index forward and
52		* wrap around at the end.
53		*/
54		private int incrementIndex(int index) {
55	1 1. incrementIndex : negated conditional → KILLED	if (index == lastIndex) {
56		return 0;
57		} else {
58	2 1. incrementIndex : Replaced integer addition with subtraction → KILLED 2. incrementIndex : replaced int return with 0 for com/renomad/minum/utils/RingBuffer::incrementIndex → KILLED	return index + 1;
59		}
60		}
61
62		public void add(T item) {
63		innerArray[nextIndex] = item;
64		nextIndex = incrementIndex(nextIndex);
65		}
66
67		public int getLimit() {
68	1 1. getLimit : replaced int return with 0 for com/renomad/minum/utils/RingBuffer::getLimit → KILLED	return limit;
69		}
70
71		/**
72		* Returns true if the data in the "myList" parameter is found
73		* within the RingBuffer.
74		*/
75		public boolean contains(List<T> myList) {
76	2 1. contains : negated conditional → KILLED 2. contains : negated conditional → KILLED	if (myList == null \|\| myList.isEmpty()) {
77		throw new UtilsException("expected a valid non-empty list to search for in the RingBuffer");
78		}
79		int myListIndex = 0;
80		int myListLength = myList.size();
81		for (var value : this) {
82	1 1. contains : negated conditional → KILLED	if (myList.get(myListIndex).equals(value)) {
83	1 1. contains : Changed increment from 1 to -1 → KILLED	myListIndex += 1;
84		} else {
85		myListIndex = 0;
86		}
87
88	1 1. contains : negated conditional → KILLED	if (myListIndex == myListLength) {
89	1 1. contains : replaced boolean return with false for com/renomad/minum/utils/RingBuffer::contains → KILLED	return true;
90		}
91
92		}
93	1 1. contains : replaced boolean return with true for com/renomad/minum/utils/RingBuffer::contains → KILLED	return false;
94		}
95
96		/**
97		* Returns true if the data in the "myList" parameter is found
98		* within the RingBuffer at the index provided.
99		*/
100		public boolean containsAt(List<T> myList, int index) {
101	2 1. containsAt : negated conditional → KILLED 2. containsAt : negated conditional → KILLED	if (myList == null \|\| myList.isEmpty()) {
102		throw new UtilsException("expected a valid non-empty list to search for in the RingBuffer");
103		}
104	4 1. containsAt : changed conditional boundary → KILLED 2. containsAt : changed conditional boundary → KILLED 3. containsAt : negated conditional → KILLED 4. containsAt : negated conditional → KILLED	if (index > lastIndex \|\| index < 0) {
105		throw new UtilsException("expected an index greater than zero and less-than-or-equal to the last index of the buffer (the limit minus one)");
106		}
107		int i = 0;
108		int myListIndex = 0;
109	1 1. containsAt : Replaced integer subtraction with addition → KILLED	int myListLastIndex = myList.size() - 1;
110		boolean comparing = false;
111		var iterator = this.iterator();
112	1 1. containsAt : negated conditional → KILLED	while (iterator.hasNext()) {
113		var value = iterator.next();
114	1 1. containsAt : negated conditional → KILLED	if (i == index) {
115		comparing = true;
116		}
117
118	1 1. containsAt : negated conditional → KILLED	if (comparing) {
119	1 1. containsAt : negated conditional → KILLED	if (! myList.get(myListIndex).equals(value)) {
120	1 1. containsAt : replaced boolean return with true for com/renomad/minum/utils/RingBuffer::containsAt → KILLED	return false;
121		}
122	1 1. containsAt : negated conditional → KILLED	if (myListIndex == myListLastIndex) {
123	1 1. containsAt : replaced boolean return with false for com/renomad/minum/utils/RingBuffer::containsAt → KILLED	return true;
124		}
125	1 1. containsAt : Changed increment from 1 to -1 → KILLED	myListIndex += 1;
126		}
127
128	1 1. containsAt : Changed increment from 1 to -1 → KILLED	i += 1;
129		}
130	1 1. containsAt : replaced boolean return with true for com/renomad/minum/utils/RingBuffer::containsAt → KILLED	return false;
131		}
132
133		@Override
134		public Iterator<T> iterator() {
135	1 1. iterator : replaced return value with null for com/renomad/minum/utils/RingBuffer::iterator → KILLED	return new Iterator<>() {
136
137		/**
138		* As we loop through the buffer, we have to use a similar
139		* technique to the "nextIndex" - wrapping around when we
140		* hit the end
141		*/
142		int iteratorIndex = nextIndex;
143		/**
144		* We'll count as we read values, stopping when we've read every slot.
145		*/
146		int count = 0;
147
148		@Override
149		public boolean hasNext() {
150	3 1. hasNext : replaced boolean return with true for com/renomad/minum/utils/RingBuffer$1::hasNext → TIMED_OUT 2. hasNext : changed conditional boundary → KILLED 3. hasNext : negated conditional → KILLED	return count < limit;
151		}
152
153		@Override
154		public T next() {
155	1 1. next : negated conditional → KILLED	if (!hasNext()) {
156		throw new NoSuchElementException();
157		}
158		var result = innerArray[iteratorIndex];
159		iteratorIndex = incrementIndex(iteratorIndex);
160	1 1. next : Replaced integer addition with subtraction → TIMED_OUT	count += 1;
161	1 1. next : replaced return value with null for com/renomad/minum/utils/RingBuffer$1::next → KILLED	return result;
162		}
163		};
164		}
165
166		/**
167		* Returns the value at the slot pointed to by the "nextIndex". Note that
168		* this will be null at first while the array starts to get filled.
169		*/
170		public T atNextIndex() {
171	1 1. atNextIndex : replaced return value with null for com/renomad/minum/utils/RingBuffer::atNextIndex → KILLED	return innerArray[nextIndex];
172		}
173
174		}
		Mutations
43		1.1 Location : <init> Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) Replaced integer subtraction with addition → KILLED
55		1.1 Location : incrementIndex Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
58		1.1 Location : incrementIndex Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) Replaced integer addition with subtraction → KILLED 2.2 Location : incrementIndex Killed by : com.renomad.minum.utils.RingBufferTests replaced int return with 0 for com/renomad/minum/utils/RingBuffer::incrementIndex → KILLED
68		1.1 Location : getLimit Killed by : com.renomad.minum.web.BoundaryBugTest replaced int return with 0 for com/renomad/minum/utils/RingBuffer::getLimit → KILLED
76		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED 2.2 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
82		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
83		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests Changed increment from 1 to -1 → KILLED
88		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
89		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests replaced boolean return with false for com/renomad/minum/utils/RingBuffer::contains → KILLED
93		1.1 Location : contains Killed by : com.renomad.minum.utils.RingBufferTests replaced boolean return with true for com/renomad/minum/utils/RingBuffer::contains → KILLED
101		1.1 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED 2.2 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED
104		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests changed conditional boundary → KILLED 2.2 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) changed conditional boundary → KILLED 3.3 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED 4.4 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED
109		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests Replaced integer subtraction with addition → KILLED
112		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
114		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
118		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
119		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED
120		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests replaced boolean return with true for com/renomad/minum/utils/RingBuffer::containsAt → KILLED
122		1.1 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED
123		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests replaced boolean return with false for com/renomad/minum/utils/RingBuffer::containsAt → KILLED
125		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests Changed increment from 1 to -1 → KILLED
128		1.1 Location : containsAt Killed by : com.renomad.minum.utils.RingBufferTests Changed increment from 1 to -1 → KILLED
130		1.1 Location : containsAt Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) replaced boolean return with true for com/renomad/minum/utils/RingBuffer::containsAt → KILLED
135		1.1 Location : iterator Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) replaced return value with null for com/renomad/minum/utils/RingBuffer::iterator → KILLED
150		1.1 Location : hasNext Killed by : com.renomad.minum.utils.RingBufferTests changed conditional boundary → KILLED 2.2 Location : hasNext Killed by : com.renomad.minum.utils.RingBufferTests negated conditional → KILLED 3.3 Location : hasNext Killed by : none replaced boolean return with true for com/renomad/minum/utils/RingBuffer$1::hasNext → TIMED_OUT
155		1.1 Location : next Killed by : com.renomad.minum.BugExposureTests.test_RingBuffer_ContainsAt_PatternExtendsBeyondBuffer(com.renomad.minum.BugExposureTests) negated conditional → KILLED
160		1.1 Location : next Killed by : none Replaced integer addition with subtraction → TIMED_OUT
161		1.1 Location : next Killed by : com.renomad.minum.utils.RingBufferTests replaced return value with null for com/renomad/minum/utils/RingBuffer$1::next → KILLED
171		1.1 Location : atNextIndex Killed by : com.renomad.minum.web.BoundaryBugTest replaced return value with null for com/renomad/minum/utils/RingBuffer::atNextIndex → KILLED

RingBuffer.java

Mutations

Active mutators

Tests examined