Added RandomValue generators

src/main/tjava/com/r35157/libs/random/RandomValueGeneratorInt.tjava

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+package com.r35157.libs.random;
+
+/**
+ * This interface provides a way to generate random integers.
+ */
+public interface RandomValueGeneratorInt {
+    /**
+     * Returns a random integer in the full range (min -2<sup>31</sup>. to max 2<sup>31</sup>-1)
+     *
+     * @return a random integer in full range
+     */
+    int getSomeInt();
+
+    /**
+     * Returns a random integer in the range provided by the parameters. Both parameters are included in the range and
+     * {@code minInclusive} must be less than {@code maxInclusive}.
+     *
+     * @return a random integer in the provided range
+     */
+    int getSomeInt(int minInclusive, int maxInclusive);
+}

src/main/tjava/com/r35157/libs/random/RandomValueGeneratorString.tjava

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+package com.r35157.libs.random;
+
+import org.jetbrains.annotations.NotNull;
+
+public interface RandomValueGeneratorString {
+    /**
+     * Generate a random Alpha Numeric String of exactly the length given as the parameter.
+     *
+     * @param length Length of generated String - cannot be negative
+     * @return A non-null random String of the length given
+     * @throws IllegalArgumentException If length is negative
+     */
+    @NotNull String getSomeStringAlphaNumericOnly(int length) throws IllegalArgumentException;
+}

src/main/tjava/com/r35157/libs/random/impl/ref/RandomValueGeneratorIntImpl.tjava

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+package com.r35157.libs.random.impl.ref;
+
+import com.r35157.libs.random.RandomValueGeneratorInt;
+
+import java.util.concurrent.ThreadLocalRandom;
+
+import static java.lang.Integer.MAX_VALUE;
+import static java.lang.Integer.MIN_VALUE;
+
+public class RandomValueGeneratorIntImpl implements RandomValueGeneratorInt {
+    @Override
+    public int getSomeInt() {
+        // Default: use the full int range
+        return getSomeInt(MIN_VALUE, MAX_VALUE);
+    }
+
+    @Override
+    public int getSomeInt(int minInclusive, int maxInclusive) {
+        if (minInclusive > maxInclusive) {
+            String errorMessage = String.format("'minInclusive' (%d) must be less than or equal to 'maxInclusive' (%d)",
+                    minInclusive, maxInclusive);
+            throw new IllegalArgumentException(errorMessage);
+        }
+
+        if (minInclusive == maxInclusive) {
+            // Edge case: only one possible value
+            return minInclusive;
+        }
+
+        // Fast path: full int range – ThreadLocalRandom.nextInt() already covers it
+        if (minInclusive == MIN_VALUE && maxInclusive == MAX_VALUE) {
+            return ThreadLocalRandom.current().nextInt();
+        }
+
+        // Use long to avoid overflow when calculating range size
+        long bound = ((long) maxInclusive - (long) minInclusive) + 1L;
+
+        if (bound <= Integer.MAX_VALUE) {
+            // Normal case: the range fits in an int
+            // nextInt(bound) gives a uniform value in [0, bound],
+            // then shift it into the target range by adding minInclusive
+            return minInclusive + ThreadLocalRandom.current().nextInt((int) bound);
+        } else {
+            // Rare case: the range is larger than Integer.MAX_VALUE
+            // (e.g. almost the full int space). Use rejection sampling:
+            // draw values until one falls within the desired interval.
+            int r;
+            do {
+                r = ThreadLocalRandom.current().nextInt();
+            } while (r < minInclusive || r > maxInclusive);
+            return r;
+        }
+    }
+}

src/main/tjava/com/r35157/libs/random/impl/ref/RandomValueGeneratorStringImpl.tjava

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+package com.r35157.libs.random.impl.ref;
+
+import com.r35157.libs.random.RandomValueGeneratorInt;
+import com.r35157.libs.random.RandomValueGeneratorString;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Objects;
+
+public class RandomValueGeneratorStringImpl implements RandomValueGeneratorString {
+    public RandomValueGeneratorStringImpl(@NotNull RandomValueGeneratorInt rvgi) {
+        Objects.requireNonNull(rvgi, "Cannot initialize with <null> RandomValueGeneratorInt!");
+        this.rvgi = rvgi;
+    }
+
+    public @NotNull String getSomeStringAlphaNumericOnly(int length) throws IllegalArgumentException {
+        if(length < 0) {
+            throw new IllegalArgumentException("Cannot generate random Strings of size " + length + "!");
+        }
+
+        //             ASCII        Range size
+        // Numeric     48-57        10
+        // Alpha upper 65-90        26
+        // Alpha lower 97-122       26
+        int totalNumberOfCandidates = 10 + 26 + 26;
+
+        StringBuilder buffer = new StringBuilder(length);
+        for (int i = 0; i < length; i++) {
+            int randomInt = rvgi.getSomeInt(0, totalNumberOfCandidates - 1);
+            int asciiIndex = convertRandomIndexToASCIIIndex(randomInt);
+
+            buffer.append((char) asciiIndex);
+        }
+
+        return buffer.toString();
+    }
+
+    private static int convertRandomIndexToASCIIIndex(int randomIndex) {
+        // RandomIndex    0...         ...9  - 10...             ...35 - 36...             ... 61
+        // ASCII values: 48...<numeric>...57 - 65...<alpha upper>...90 - 97...<alpha lower>...122
+        int asciiIndex;
+
+        if(randomIndex >= 36) {
+            asciiIndex = 97 + (randomIndex - 36);
+        } else if(randomIndex >= 10) {
+            asciiIndex = 65 + (randomIndex - 10);
+        } else {
+            asciiIndex = 48 + randomIndex;
+        }
+
+        return asciiIndex;
+    }
+
+    private RandomValueGeneratorInt rvgi;
+}