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/*
* Copyright (C) 2002-2017 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.chars;
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 Char2IntFunction extends Function, java.util.function.IntUnaryOperator {
/**
* {@inheritDoc}
*
*
* In this default implementation, the key gets narrowed down to the actual key
* type, throwing an exception if the given key can't be represented in the
* restricted domain. This is done for interoperability with the Java 8 function
* environment. Its use is discouraged, as unexpected errors can occur. Instead,
* the corresponding classes should be used (e.g.,
* {@link it.unimi.dsi.fastutil.ints.Int2IntFunction} instead of
* {@link it.unimi.dsi.fastutil.shorts.Short2IntFunction}).
*
* @throws IllegalArgumentException
* If the given operand is not an element of the key domain.
* @since 8.0.0
* @deprecated Please use primitive types which don't have to be widened as
* keys.
*/
@Deprecated
@Override
default int applyAsInt(int operand) {
return get(it.unimi.dsi.fastutil.SafeMath.safeIntToChar(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 int put(final char key, final int 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)
*/
int get(char key);
/**
* 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 int remove(final char key) {
throw new UnsupportedOperationException();
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Integer put(final Character key, final Integer value) {
final char k = (key).charValue();
final boolean containsKey = containsKey(k);
final int v = put(k, (value).intValue());
return containsKey ? Integer.valueOf(v) : null;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Integer get(final Object key) {
if (key == null)
return null;
final char k = ((Character) (key)).charValue();
final int v = get(k);
return (v != defaultReturnValue() || containsKey(k)) ? Integer.valueOf(v) : null;
}
/**
* {@inheritDoc}
*
* @deprecated Please use the corresponding type-specific method instead.
*/
@Deprecated
@Override
default Integer remove(final Object key) {
if (key == null)
return null;
final char k = ((Character) (key)).charValue();
return containsKey(k) ? Integer.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(char 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(((Character) (key)).charValue());
}
/**
* 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(int 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 int defaultReturnValue() {
return (0);
}
}