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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.HashSet;

/**
 * Invocation filtering out inputs which are not unique (according to the {@code equals(Object)}
 * method).
 * 

* Created by davide-maestroni on 05/01/2016. * * @param the data type. */ class DistinctInvocation extends TemplateInvocation { private static final InvocationFactory sFactory = new InvocationFactory(null) { @NotNull @Override public Invocation newInvocation() { return new DistinctInvocation(); } }; private HashSet mSet; /** * Constructor. */ private DistinctInvocation() { } /** * Returns a factory of invocations filtering out inputs which are not unique. * * @param the data type. * @return the factory instance. */ @NotNull @SuppressWarnings("unchecked") static InvocationFactory factoryOf() { return (InvocationFactory) sFactory; } @Override public void onInput(final DATA input, @NotNull final Channel result) { if (mSet.add(input)) { result.pass(input); } } @Override public void onRecycle(final boolean isReused) { mSet = null; } @Override public void onRestart() { mSet = new HashSet(); } }