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.predicate.bi.obj.ObjDoublePredicate.java

/**
 * Returns a memoized (caching) version of this {@link ObjDoublePredicate}. 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 2s.c  om*/
 * Unless the predicate and therefore the used cache will be garbage-collected, it will keep all memoized values
 * forever.
 *
 * @return A memoized (caching) version of this {@code ObjDoublePredicate}.
 * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the
 * resulting memoized predicate, as the cache used internally does not permit {@code null} keys or values.
 * @implNote The returned memoized predicate can be safely used concurrently from multiple threads which makes it
 * thread-safe.
 */
@Nonnull
default ObjDoublePredicate<T> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Pair<T, Double>, Boolean> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (ObjDoublePredicate<T> & Memoized) (t, value) -> {
            final boolean returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Pair.of(t, value),
                        key -> test(key.getLeft(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjByteToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjByteToCharFunction}. 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  va2 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 BiObjByteToCharFunction}.
 * @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 BiObjByteToCharFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Byte>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjByteToCharFunction<T, U> & Memoized) (t, u, value) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsChar(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjCharToByteFunction.java

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

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjDoubleToByteFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjDoubleToByteFunction}. 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. java2s.com
 * 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 BiObjDoubleToByteFunction}.
 * @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 BiObjDoubleToByteFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Double>, Byte> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjDoubleToByteFunction<T, U> & Memoized) (t, u, value) -> {
            final byte returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsByte(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjIntToFloatFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjIntToFloatFunction}. 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 .java2 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 BiObjIntToFloatFunction}.
 * @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 BiObjIntToFloatFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Integer>, Float> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjIntToFloatFunction<T, U> & Memoized) (t, u, value) -> {
            final float returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsFloat(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjIntToShortFunction.java

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

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjLongToCharFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjLongToCharFunction}. 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. ja va 2s  .  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 BiObjLongToCharFunction}.
 * @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 BiObjLongToCharFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Long>, Character> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjLongToCharFunction<T, U> & Memoized) (t, u, value) -> {
            final char returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsChar(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjBooleanToByteFunction.java

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

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjCharToLongFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjCharToLongFunction}. 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 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 BiObjCharToLongFunction}.
 * @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 BiObjCharToLongFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Character>, Long> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjCharToLongFunction<T, U> & Memoized) (t, u, value) -> {
            final long returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsLong(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}

From source file:at.gridtec.lambda4j.function.tri.obj.BiObjFloatToShortFunction.java

/**
 * Returns a memoized (caching) version of this {@link BiObjFloatToShortFunction}. 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.jav  a 2 s  .  com
 * 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 BiObjFloatToShortFunction}.
 * @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 BiObjFloatToShortFunction<T, U> memoized() {
    if (isMemoized()) {
        return this;
    } else {
        final Map<Triple<T, U, Float>, Short> cache = new ConcurrentHashMap<>();
        final Object lock = new Object();
        return (BiObjFloatToShortFunction<T, U> & Memoized) (t, u, value) -> {
            final short returnValue;
            synchronized (lock) {
                returnValue = cache.computeIfAbsent(Triple.of(t, u, value),
                        key -> applyAsShort(key.getLeft(), key.getMiddle(), key.getRight()));
            }
            return returnValue;
        };
    }
}