firstException = expected;
    // Second time should also fail, with a cached causal chain.
    expected = assertThrows(PotentialDeadlockException.class, () -> lockA.lock());
    checkMessage(expected, "LockB -> LockA", "LockA -> LockB");
    // The causal chain should be cached.
    assertSame(firstException.getCause(), expected.getCause());
    // lockA should work after lockB is released.

{* ../../docs_src/extending_openapi/tutorial001.py hl[22:24] *}

### Cache the OpenAPI schema { #cache-the-openapi-schema }

You can use the property `.openapi_schema` as a "cache", to store your generated schema.

That way, your application won't have to generate the schema every time a user opens your API docs.

It will be generated only once, and then the same cached schema will be used for the next requests.

import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * A map-like data structure that wraps a backing map and caches values while iterating through
 * {@link #unmodifiableKeySet()}. By design, the cache is cleared when this structure is mutated. If
 * this structure is never mutated, it provides a thread-safe view of the backing map.
 *

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.cache2

import assertk.assertThat
import assertk.assertions.isEqualTo
import java.io.File
import java.io.RandomAccessFile
import java.util.Random
import kotlin.test.assertFailsWith
import okio.Buffer

    }

    /**
     * Creates a path matcher function for path mapping.
     *
     * @param matcher the regex matcher
     * @param replacement the replacement string
     * @return the path matcher function
     */
    public BiFunction<String, Matcher, String> createPathMatcher(final Matcher matcher, final String replacement) { // for PathMapping

    /**
     * Gets a buffer from the cache or creates a new one if the cache is empty.
     *
     * Performance: O(1) operation using concurrent queue
     *
     * @return a byte buffer for SMB operations
     * @throws IllegalStateException if buffer size exceeds maximum allowed
     */
    static public byte[] getBuffer() {
        // Try to get from cache first - O(1) operation
        byte[] buf = bufferQueue.poll();

/**
 * Statistics about the performance of a {@link Cache}. Instances of this class are immutable.
 *
 * <p>Cache statistics are incremented according to the following rules:
 *
 * <ul>
 *   <li>When a cache lookup encounters an existing cache entry {@code hitCount} is incremented.
 *   <li>When a cache lookup first encounters a missing cache entry, a new entry is loaded.
 *       <ul>

    private static final Logger logger = LogManager.getLogger(PopularWordHelper.class);

    /** Character used to separate cache key components */
    protected static final char CACHE_KEY_SPLITTER = '\n';

    /** Cache for storing popular word lists */
    protected Cache<String, List<String>> cache;

    /** Fess configuration instance */
    protected FessConfig fessConfig;

    /**
     * Default constructor.
     */

    /** Number of buffers to keep in cache */
    protected int bufferCacheSize = 16;
    /** Maximum size for list operations */
    protected int smbListSize = 65435;
    /** Maximum number of entries to return in list operations */
    protected int smbListCount = 200;
    /** Time in milliseconds before cached file attributes expire */
    protected long smbAttributeExpiration = 5000L;

### Die `Settings` nur einmal laden mittels `lru_cache`

Das Lesen einer Datei von der Festplatte ist normalerweise ein kostspieliger (langsamer) Vorgang, daher möchten Sie ihn wahrscheinlich nur einmal ausführen und dann dasselbe Einstellungsobjekt erneut verwenden, anstatt es für jeden Request zu lesen.