com.github.dm.jrt.operator.DistinctIdentityInvocation Maven / Gradle / Ivy

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/*
 * Copyright 2016 Davide Maestroni
 *
 * 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.github.dm.jrt.operator;

import com.github.dm.jrt.core.channel.Channel;
import com.github.dm.jrt.core.invocation.Invocation;
import com.github.dm.jrt.core.invocation.InvocationFactory;
import com.github.dm.jrt.core.invocation.TemplateInvocation;

import org.jetbrains.annotations.NotNull;

import java.util.IdentityHashMap;

/**
 * Invocation filtering out inputs which are not unique (according to identity comparison).
 * 
 * Created by davide-maestroni on 07/09/2016.
 *
 * @param  the data type.
 */
class DistinctIdentityInvocation extends TemplateInvocation {

  private static final Object PLACEHOLDER = new Object();

  private static final InvocationFactory sFactory =
      new InvocationFactory(null) {

        @NotNull
        @Override
        public Invocation newInvocation() {
          return new DistinctIdentityInvocation