Added utility to execute functions within a time limit

src/main/java/io/github/pixee/security/ExecuteWithTimeout.java

@@ -0,0 +1,25 @@
+package io.github.pixee.security;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Holds utilities for executing methods and functions within a timeout.
+ */
+public class ExecuteWithTimeout{
+
+
+	/**
+	 * Tries to execute a given {@link Callable} within a given timeout in milliseconds. Returns the result if successful, otherwise throws a {@link RuntimeException}.
+	 */
+	public static <E> E executeWithTimeout(final Callable<E> action, final int timeout) {
+        Future<E> maybeResult = Executors.newSingleThreadExecutor().submit(action);
+        try {
+            return maybeResult.get(timeout, TimeUnit.MILLISECONDS);
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to execute within time limit.");
+        }
+    }
+}

src/test/java/io/github/pixee/security/ExecuteWithTimeoutTest.java

@@ -0,0 +1,36 @@
+package io.github.pixee.security;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+final class ExecuteWithTimeoutTest {
+
+  @Test
+  void it_executes_within_timeout_and_returns(){
+    Pattern pat = Pattern.compile("string");
+    String input = "some very long string";
+    Matcher matcher = pat.matcher(input);
+    boolean result = ExecuteWithTimeout.executeWithTimeout(() -> matcher.find(), 5000);
+    assertThat(result, is(equalTo(true)));
+  }
+
+  @Test
+  void it_throws_exception_due_to_timeout(){
+    Pattern pat = Pattern.compile("string");
+    String input = "some very long string";
+    Matcher matcher = pat.matcher(input);
+    RuntimeException exception = assertThrows(
+        RuntimeException.class,
+        () -> ExecuteWithTimeout.executeWithTimeout(() -> matcher.find(), 0)
+        );
+    assertThat(exception.getMessage(), is(equalTo("Failed to execute within time limit.")));
+  }
+
+}