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.obj.ObjFloatToShortFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjFloatToShortFunction}. 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 . ja  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 ObjFloatToShortFunction}.
 * @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 ObjFloatToShortFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Float>, Short> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjFloatToShortFunction<T> & Memoized) (t, value) -> {
            final short returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsShort(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjShortToFloatFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjShortToFloatFunction}. 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 ww  . ja 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 ObjShortToFloatFunction}.
 * @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 ObjShortToFloatFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Short>, Float> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjShortToFloatFunction<T> & Memoized) (t, value) -> {
            final float returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsFloat(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjBooleanToByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjBooleanToByteFunction}. 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  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 ObjBooleanToByteFunction}.
 * @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 ObjBooleanToByteFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Boolean>, Byte> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjBooleanToByteFunction<T> & Memoized) (t, value) -> {
            final byte returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsByte(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjCharToIntFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjCharToIntFunction}. 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 ww  .  j av a  2s  .  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 ObjCharToIntFunction}.
 * @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 ObjCharToIntFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Character>, Integer> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjCharToIntFunction<T> & Memoized) (t, value) -> {
            final int returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsInt(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjDoubleToLongFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjDoubleToLongFunction}. 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  ww . j a va  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 ObjDoubleToLongFunction}.
 * @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 ObjDoubleToLongFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Double>, Long> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjDoubleToLongFunction<T> & Memoized) (t, value) -> {
            final long returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsLong(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjFloatToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjFloatToCharFunction}. 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  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 ObjFloatToCharFunction}.
 * @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 ObjFloatToCharFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Float>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjFloatToCharFunction<T> & Memoized) (t, value) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjIntToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjIntToCharFunction}. 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  ww.  j  ava2s . 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 ObjIntToCharFunction}.
 * @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 ObjIntToCharFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Integer>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjIntToCharFunction<T> & Memoized) (t, value) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjShortToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjShortToCharFunction}. 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.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 ObjShortToCharFunction}.
 * @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 ObjShortToCharFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Short>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjShortToCharFunction<T> & Memoized) (t, value) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsChar(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjBooleanToLongFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjBooleanToLongFunction}. 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 av a  2s  .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 ObjBooleanToLongFunction}.
 * @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 ObjBooleanToLongFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Boolean>, Long> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjBooleanToLongFunction<T> & Memoized) (t, value) -> {
            final long returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsLong(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

From source file:at.gridtec.lambda4j.function.bi.obj.ObjByteToDoubleFunction.java

/**
 * Returns a memoized (caching) version of this {@link ObjByteToDoubleFunction}. 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 ava  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 ObjByteToDoubleFunction}.
 * @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 ObjByteToDoubleFunction<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Byte>, Double> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjByteToDoubleFunction<T> & Memoized) (t, value) -> {
            final double returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> applyAsDouble(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

---

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