Example usage for java.util Map computeIfAbsent

Introduction

In this page you can find the example usage for java.util Map computeIfAbsent.

Prototype

default V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) 

Source Link

Document

If the specified key is not already associated with a value (or is mapped to null ), attempts to compute its value using the given mapping function and enters it into this map unless null .

Usage

From source file:at.gridtec.lambda4j.function.bi.conversion.BiShortToByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiShortToByteFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//from  w  w  w  .  j  a v a2  s  .  c  o  m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiShortToByteFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiShortToByteFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Short, Short>, Byte> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiShortToByteFunction & Memoized) (value1, value2) -> {
            final byte returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsByte(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiShortToLongFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiShortToLongFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*  w w w. j av a 2  s .  c  o m*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiShortToLongFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiShortToLongFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Short, Short>, Long> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiShortToLongFunction & Memoized) (value1, value2) -> {
            final long returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsLong(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiFloatToIntFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiFloatToIntFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>// w w w  . j  a v  a2s  .  c o  m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiFloatToIntFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiFloatToIntFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Float, Float>, Integer> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiFloatToIntFunction & Memoized) (value1, value2) -> {
            final int returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsInt(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiShortToIntFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiShortToIntFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//  ww w.  j a  va  2s . co  m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiShortToIntFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiShortToIntFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Short, Short>, Integer> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiShortToIntFunction & Memoized) (value1, value2) -> {
            final int returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsInt(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiByteToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiByteToCharFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>// w  w w .java 2 s . co m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiByteToCharFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiByteToCharFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Byte, Byte>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiByteToCharFunction & Memoized) (value1, value2) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiIntToByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiIntToByteFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*from ww w. j  ava  2 s .co  m*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiIntToByteFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiIntToByteFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Integer, Integer>, Byte> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiIntToByteFunction & Memoized) (value1, value2) -> {
            final byte returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsByte(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiLongToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiLongToCharFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*from  www.j a v  a 2  s  .  c  om*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiLongToCharFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiLongToCharFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Long, Long>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiLongToCharFunction & Memoized) (value1, value2) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiIntToLongFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiIntToLongFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>/*from   ww w  .j av  a  2  s  .c om*/
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiIntToLongFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiIntToLongFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Integer, Integer>, Long> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiIntToLongFunction & Memoized) (value1, value2) -> {
            final long returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsLong(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiByteToDoubleFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiByteToDoubleFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//from   w  w w .j a  v a  2  s .  c om
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiByteToDoubleFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiByteToDoubleFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Byte, Byte>, Double> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiByteToDoubleFunction & Memoized) (value1, value2) -> {
            final double returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsDouble(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.conversion.BiDoubleToByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiDoubleToByteFunction}. Whenever it is called, the mapping
 * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the
 * memoized value instead of computing the return value again.
 * <p>//from   w  w w.  java2s .  c o  m
 * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code BiDoubleToByteFunction}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized function, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default BiDoubleToByteFunction memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<Double, Double>, Byte> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiDoubleToByteFunction & Memoized) (value1, value2) -> {
            final byte returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(value1, value2),
                        key -> applyAsByte(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

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