platform/util-rt/src/com/intellij/util/NullableFunction.java

/*
 * Copyright 2000-2012 JetBrains s.r.o.
 *
 * 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 com.intellij.util;

import org.jetbrains.annotations.Nullable;

/**
 * @author peter
 */
public interface NullableFunction<Param, Result> extends Function<Param, Result> {
  @Nullable
  Result fun(final Param param);

  /**
   * @see FunctionUtil#nullConstant()
   */
  NullableFunction NULL = new NullableFunction() {
    public Object fun(final Object o) {
      return null;
    }
  };
}