From 0d04dd505190d959e6d2cde16da54b2cb638699a Mon Sep 17 00:00:00 2001
From: irengrig <Irina.Chernushina@jetbrains.com>
Date: Tue, 5 Jul 2011 13:35:41 +0400
Subject: [PATCH] VCS: producer-consumer. Not used now (no performance
 increase) but maybe would be useful

---
 .../com/intellij/util/ProducerConsumer.java   | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 platform/util/src/com/intellij/util/ProducerConsumer.java

diff --git a/platform/util/src/com/intellij/util/ProducerConsumer.java b/platform/util/src/com/intellij/util/ProducerConsumer.java
new file mode 100644
index 000000000000..7395bdb72943
--- /dev/null
+++ b/platform/util/src/com/intellij/util/ProducerConsumer.java
@@ -0,0 +1,92 @@
+/*
+ * Copyright 2000-2011 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 java.util.ArrayDeque;
+
+/**
+ * @author irengrig
+ *         Date: 7/5/11
+ *         Time: 1:48 AM
+ */
+public class ProducerConsumer<T> {
+  public static final int ourDefaultMaxSize = 20;
+
+  private final ArrayDeque<T> myQueue;
+  private final Consumer<T> myConsumer;
+  private final int myMaxSize;
+  private final Object myLock;
+  private final Thread myConsumerThread;
+  private boolean myIsAlive;
+
+  public ProducerConsumer(final Consumer<T> consumer) {
+    this(consumer, ourDefaultMaxSize);
+  }
+
+  public void start() {
+    myIsAlive = true;
+    myConsumerThread.start();
+  }
+
+  public void stop() {
+    synchronized (myLock) {
+      myIsAlive = false;
+      myLock.notifyAll();
+    }
+  }
+
+  public ProducerConsumer(final Consumer<T> consumer, final int maxSize) {
+    myConsumer = consumer;
+    myQueue = new ArrayDeque<T>();
+    myMaxSize = maxSize;
+    myLock = new Object();
+    myConsumerThread = new Thread(new Runnable() {
+      @Override
+      public void run() {
+        synchronized (myLock) {
+          while (myIsAlive) {
+            if (! myQueue.isEmpty()) {
+              myConsumer.consume(myQueue.removeFirst());
+            } else {
+              try {
+                myLock.wait(10);
+              }
+              catch (InterruptedException e) {
+                //
+              }
+            }
+          }
+        }
+      }
+    });
+  }
+
+  public void produce(final T t) {
+    synchronized (myLock) {
+      while (myQueue.size() >= myMaxSize) {
+        try {
+          myLock.notifyAll();
+          myLock.wait(10);
+        }
+        catch (InterruptedException e) {
+          //
+        }
+      }
+      myQueue.addLast(t);
+      myLock.notifyAll();
+    }
+  }
+}