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/*
* Copyright (C) 2002-2021 Sebastiano Vigna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* 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 it.unimi.dsi.fastutil.doubles;
import it.unimi.dsi.fastutil.Function;
/**
* A type-specific {@link Function}; provides some additional methods that use
* polymorphism to avoid (un)boxing.
*
*
* Type-specific versions of {@code get()}, {@code put()} and {@code remove()}
* cannot rely on {@code null} to denote absence of a key. Rather, they return a
* {@linkplain #defaultReturnValue() default return value}, which is set to
* 0/false at creation, but can be changed using the
* {@code defaultReturnValue()} method.
*
*
* For uniformity reasons, even functions returning objects implement the
* default return value (of course, in this case the default return value is
* initialized to {@code null}).
*
*
* The default implementation of optional operations just throw an
* {@link UnsupportedOperationException}, except for the type-specific {@code
* containsKey()}, which return true. Generic versions of accessors delegate to
* the corresponding type-specific counterparts following the interface rules.
*
*
* Warning: to fall in line as much as possible with the
* {@linkplain java.util.Map standard map interface}, it is required that
* standard versions of {@code get()}, {@code put()} and {@code remove()} for
* maps with primitive-type keys or values return {@code null} to denote
* missing keys rather than wrap the default return value in an object. In
* case both keys and values are reference types, the default return value must
* be returned instead, thus violating the {@linkplain java.util.Map standard
* map interface} when the default return value is not {@code null}.
*
* @see Function
*/
@FunctionalInterface
public interface Double2DoubleFunction extends Function, java.util.function.DoubleUnaryOperator {
/**
* {@inheritDoc}
*
* @since 8.0.0
*/
@Override
default double applyAsDouble(double operand) {
return get(operand);
}
/**
* Adds a pair to the map (optional operation).
*
* @param key
* the key.
* @param value
* the value.
* @return the old value, or the {@linkplain #defaultReturnValue() default
* return value} if no value was present for the given key.
* @see Function#put(Object,Object)
*/
default double put(final double key, final double value) {
throw new UnsupportedOperationException();
}
/**
* Returns the value to which the given key is mapped.
*
* @param key
* the key.
* @return the corresponding value, or the {@linkplain #defaultReturnValue()
* default return value} if no value was present for the given key.
* @see Function#get(Object)
*/
double get(double key);
/**
* Returns the value associated by this function to the specified key, or give
* the specified value if not present.
*
* @param key
* the key.
* @param defaultValue
* the value to return if not present.
* @return the corresponding value, or {@code defaultValue} if no value was
* present for the given key.
* @see Function#getOrDefault(Object, Object)
* @since 8.5.0
*/
default double getOrDefault(final double key, final double defaultValue) {
final double v;
return ((v = get(key)) != defaultReturnValue() || containsKey(key)) ? v : defaultValue;
}
/**
* Removes the mapping with the given key (optional operation).
*
* @param key
* the key.
* @return the old value, or the {@linkplain #defaultReturnValue() default
* return value} if no value was present for the given key.
* @see Function#remove(Object)
*/
default double remove(final double key) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Double put(final Double key, final Double value) {
final double k = (key).doubleValue();
final boolean containsKey = containsKey(k);
final double v = put(k, (value).doubleValue());
return containsKey ? Double.valueOf(v) : null;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Double get(final Object key) {
if (key == null)
return null;
final double k = ((Double) (key)).doubleValue();
final double v;
return ((v = get(k)) != defaultReturnValue() || containsKey(k)) ? Double.valueOf(v) : null;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Double getOrDefault(final Object key, Double defaultValue) {
if (key == null)
return defaultValue;
final double k = ((Double) (key)).doubleValue();
final double v = get(k);
return (v != defaultReturnValue() || containsKey(k)) ? Double.valueOf(v) : defaultValue;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Double remove(final Object key) {
if (key == null)
return null;
final double k = ((Double) (key)).doubleValue();
return containsKey(k) ? Double.valueOf(remove(k)) : null;
}
/**
* Returns true if this function contains a mapping for the specified key.
*
*
* Note that for some kind of functions (e.g., hashes) this method will always
* return true. In particular, this default implementation always returns true.
*
* @param key
* the key.
* @return true if this function associates a value to {@code key}.
* @see Function#containsKey(Object)
*/
default boolean containsKey(double key) {
return true;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default boolean containsKey(final Object key) {
return key == null ? false : containsKey(((Double) (key)).doubleValue());
}
/**
* Sets the default return value (optional operation).
*
* This value must be returned by type-specific versions of {@code get()},
* {@code put()} and {@code remove()} to denote that the map does not contain
* the specified key. It must be 0/{@code false}/{@code null} by default.
*
* @param rv
* the new default return value.
* @see #defaultReturnValue()
*/
default void defaultReturnValue(double rv) {
throw new UnsupportedOperationException();
}
/**
* Gets the default return value.
*
*
* This default implementation just return the default null value of the type
* ({@code null} for objects, 0 for scalars, false for Booleans).
*
* @return the current default return value.
*/
default double defaultReturnValue() {
return (0);
}
static Double2DoubleFunction identity() {
return k -> k;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default java.util.function.Function compose(
java.util.function.Function before) {
return Function.super.compose(before);
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default java.util.function.Function andThen(
java.util.function.Function after) {
return Function.super.andThen(after);
}
default it.unimi.dsi.fastutil.doubles.Double2ByteFunction andThenByte(
it.unimi.dsi.fastutil.doubles.Double2ByteFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.bytes.Byte2DoubleFunction composeByte(
it.unimi.dsi.fastutil.bytes.Byte2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2ShortFunction andThenShort(
it.unimi.dsi.fastutil.doubles.Double2ShortFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.shorts.Short2DoubleFunction composeShort(
it.unimi.dsi.fastutil.shorts.Short2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2IntFunction andThenInt(
it.unimi.dsi.fastutil.doubles.Double2IntFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.ints.Int2DoubleFunction composeInt(
it.unimi.dsi.fastutil.ints.Int2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2LongFunction andThenLong(
it.unimi.dsi.fastutil.doubles.Double2LongFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.longs.Long2DoubleFunction composeLong(
it.unimi.dsi.fastutil.longs.Long2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2CharFunction andThenChar(
it.unimi.dsi.fastutil.doubles.Double2CharFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.chars.Char2DoubleFunction composeChar(
it.unimi.dsi.fastutil.chars.Char2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2FloatFunction andThenFloat(
it.unimi.dsi.fastutil.doubles.Double2FloatFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.floats.Float2DoubleFunction composeFloat(
it.unimi.dsi.fastutil.floats.Float2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2DoubleFunction andThenDouble(
it.unimi.dsi.fastutil.doubles.Double2DoubleFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2DoubleFunction composeDouble(
it.unimi.dsi.fastutil.doubles.Double2DoubleFunction before) {
return k -> get(before.get(k));
}
default it.unimi.dsi.fastutil.doubles.Double2ObjectFunction andThenObject(
it.unimi.dsi.fastutil.doubles.Double2ObjectFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.objects.Object2DoubleFunction composeObject(
it.unimi.dsi.fastutil.objects.Object2DoubleFunction before) {
return k -> get(before.getDouble(k));
}
default it.unimi.dsi.fastutil.doubles.Double2ReferenceFunction andThenReference(
it.unimi.dsi.fastutil.doubles.Double2ReferenceFunction after) {
return k -> after.get(get(k));
}
default it.unimi.dsi.fastutil.objects.Reference2DoubleFunction composeReference(
it.unimi.dsi.fastutil.objects.Reference2DoubleFunction before) {
return k -> get(before.getDouble(k));
}
}