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src/java.base/share/classes/java/util/function/BiFunction.java

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   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.util.function;
  26 
  27 import java.util.Objects;
  28 
  29 /**
  30  * Represents a function that accepts two arguments and produces a result.
  31  * This is the two-arity specialization of {@link Function}.
  32  *
  33  * <p>This is a <a href="package-summary.html">functional interface</a>
  34  * whose functional method is {@link #apply(Object, Object)}.
  35  *
  36  * @param <T> the type of the first argument to the function
  37  * @param <U> the type of the second argument to the function
  38  * @param <R> the type of the result of the function
  39  *
  40  * @see Function
  41  * @since 1.8
  42  */
  43 @FunctionalInterface
  44 public interface BiFunction<T, U, R> {
  45 
  46     /**
  47      * Applies this function to the given arguments.
  48      *
  49      * @param t the first function argument
  50      * @param u the second function argument
  51      * @return the function result
  52      */
  53     R apply(T t, U u);
  54 
  55     /**
  56      * Returns a composed function that first applies this function to
  57      * its input, and then applies the {@code after} function to the result.
  58      * If evaluation of either function throws an exception, it is relayed to
  59      * the caller of the composed function.
  60      *
  61      * @param <V> the type of output of the {@code after} function, and of the
  62      *           composed function
  63      * @param after the function to apply after this function is applied
  64      * @return a composed function that first applies this function and then
  65      * applies the {@code after} function
  66      * @throws NullPointerException if after is null
  67      */
  68     default <V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) {
  69         Objects.requireNonNull(after);
  70         return (T t, U u) -> after.apply(apply(t, u));
  71     }
  72 }


   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package javany.util.function;
  26 
  27 import java.util.Objects;
  28 
  29 /**
  30  * Represents a function that accepts two arguments and produces a result.
  31  * This is the two-arity specialization of {@link Function}.
  32  *
  33  * <p>This is a <a href="package-summary.html">functional interface</a>
  34  * whose functional method is {@link #apply(Object, Object)}.
  35  *
  36  * @param <T> the type of the first argument to the function
  37  * @param <U> the type of the second argument to the function
  38  * @param <R> the type of the result of the function
  39  *
  40  * @see Function
  41  * @since 1.8
  42  */
  43 @FunctionalInterface
  44 public interface BiFunction<any T, any U, any R> {
  45 
  46     /**
  47      * Applies this function to the given arguments.
  48      *
  49      * @param t the first function argument
  50      * @param u the second function argument
  51      * @return the function result
  52      */
  53     R apply(T t, U u);
  54 
  55     /**
  56      * Returns a composed function that first applies this function to
  57      * its input, and then applies the {@code after} function to the result.
  58      * If evaluation of either function throws an exception, it is relayed to
  59      * the caller of the composed function.
  60      *
  61      * @param <V> the type of output of the {@code after} function, and of the
  62      *           composed function
  63      * @param after the function to apply after this function is applied
  64      * @return a composed function that first applies this function and then
  65      * applies the {@code after} function
  66      * @throws NullPointerException if after is null
  67      */
  68     default <any V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) {
  69         Objects.requireNonNull(after);
  70         return (T t, U u) -> after.apply(apply(t, u));
  71     }
  72 }
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