init

.gitignore

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+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

.idea/.gitignore

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+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/encodings.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" defaultCharsetForPropertiesFiles="UTF-8">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+    <file url="PROJECT" charset="UTF-8" />
+  </component>
+</project>

.idea/git_toolbox_blame.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GitToolBoxBlameSettings">
+    <option name="version" value="2" />
+  </component>
+</project>

.idea/misc.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>test</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>8</maven.compiler.source>
+        <maven.compiler.target>8</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+</project>

src/main/java/org/example/Main.java

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+package org.example;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class Main {
+    public static void main(String[] args) {
+        Queue<Integer> pool = new ConcurrentLinkedQueue<>();
+        for (int i = 0; i < 400; i++) {
+            pool.add(i);
+        }
+        CountDownLatch latch = new CountDownLatch(10000);
+        Semaphore semaphore = new Semaphore(400);
+        Map<Integer, Integer> map = new HashMap<>();
+        Map<Integer, AtomicInteger> map2 = new HashMap<>();
+        for (int i = 0; i < 400; i++) {
+            map.put(i, getNum(i));
+            map2.put(i, new AtomicInteger(0));
+        }
+        for (int i = 0; i < 10000; i++) {
+            try {
+                semaphore.acquire();
+            } catch (InterruptedException e) {
+                throw new RuntimeException(e);
+            }
+            new Thread(new Runnable() {
+                public void run() {
+                    int count = 0, over = 0;
+                    while (count++ < 400) {
+                        Integer poll = pool.poll();
+//                        if (poll == null) System.out.println("null");
+//                        synchronized (Objects.requireNonNull(poll)) {
+                            if (checkNum(poll)) {
+//                            System.out.println(Thread.currentThread().getName() + ": "+poll);
+                                pool.add(poll);
+                                latch.countDown();
+                                map2.get(poll).incrementAndGet();
+                                over = 1;
+                                break;
+                            } else {
+                                pool.add(poll);
+//                            }
+                        }
+                    }
+                    if (over == 0) {
+                        System.out.println("over");
+                        latch.countDown();
+                    }
+                    semaphore.release();
+                }
+
+                private boolean checkNum(Integer poll) {
+                    try {
+                        Thread.sleep(2000);
+                        if (map2.get(poll).get() < map.get(poll)) {
+                            return true;
+                        }
+                    } catch (InterruptedException e) {
+                        throw new RuntimeException(e);
+                    }
+                    return false;
+                }
+            }).start();
+        }
+        try {
+            latch.await();
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        }
+        System.out.println("Hello world!");
+        System.out.println(map2);
+        System.out.println(map);
+    }
+
+    private static Integer getNum(int i) {
+        if (i % 2 == 0) {
+            return 40;
+        } else {
+            return 10;
+        }
+    }
+}