YARN-7115. Move BoundedAppender to org.hadoop.yarn.util pacakge

(Contributed by Jian He via Daniel Templeton)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/pom.xml

@@ -108,6 +108,15 @@
       <groupId>org.apache.hadoop</groupId>
       <artifactId>hadoop-annotations</artifactId>
     </dependency>
+    <!--
+    junit must be before mockito-all on the classpath.  mockito-all bundles its
+    own copy of the hamcrest classes, but they don't match our junit version.
+    -->
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-all</artifactId>
@@ -128,11 +137,6 @@
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
     </dependency>
-    <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.bouncycastle</groupId>
       <artifactId>bcprov-jdk16</artifactId>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/BoundedAppender.java

@@ -0,0 +1,142 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.hadoop.yarn.util;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Preconditions;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * A {@link CharSequence} appender that considers its {@link #limit} as upper
+ * bound.
+ * <p>
+ * When {@link #limit} would be reached on append, past messages will be
+ * truncated from head, and a header telling the user about truncation will be
+ * prepended, with ellipses in between header and messages.
+ * <p>
+ * Note that header and ellipses are not counted against {@link #limit}.
+ * <p>
+ * An example:
+ *
+ * <pre>
+ * {@code
+ *   // At the beginning it's an empty string
+ *   final Appendable shortAppender = new BoundedAppender(80);
+ *   // The whole message fits into limit
+ *   shortAppender.append(
+ *       "message1 this is a very long message but fitting into limit\n");
+ *   // The first message is truncated, the second not
+ *   shortAppender.append("message2 this is shorter than the previous one\n");
+ *   // The first message is deleted, the second truncated, the third
+ *   // preserved
+ *   shortAppender.append("message3 this is even shorter message, maybe.\n");
+ *   // The first two are deleted, the third one truncated, the last preserved
+ *   shortAppender.append("message4 the shortest one, yet the greatest :)");
+ *   // Current contents are like this:
+ *   // Diagnostic messages truncated, showing last 80 chars out of 199:
+ *   // ...s is even shorter message, maybe.
+ *   // message4 the shortest one, yet the greatest :)
+ * }
+ * </pre>
+ * <p>
+ * Note that <tt>null</tt> values are {@link #append(CharSequence) append}ed
+ * just like in {@link StringBuilder#append(CharSequence) original
+ * implementation}.
+ * <p>
+ * Note that this class is not thread safe.
+ */
+
+@InterfaceAudience.Public
+@InterfaceStability.Unstable
+@VisibleForTesting
+public class BoundedAppender {
+  @VisibleForTesting
+  public static final String TRUNCATED_MESSAGES_TEMPLATE =
+      "Diagnostic messages truncated, showing last "
+          + "%d chars out of %d:%n...%s";
+
+  private final int limit;
+  private final StringBuilder messages = new StringBuilder();
+  private int totalCharacterCount = 0;
+
+  public BoundedAppender(final int limit) {
+    Preconditions.checkArgument(limit > 0, "limit should be positive");
+
+    this.limit = limit;
+  }
+
+  /**
+   * Append a {@link CharSequence} considering {@link #limit}, truncating
+   * from the head of {@code csq} or {@link #messages} when necessary.
+   *
+   * @param csq the {@link CharSequence} to append
+   * @return this
+   */
+  public BoundedAppender append(final CharSequence csq) {
+    appendAndCount(csq);
+    checkAndCut();
+
+    return this;
+  }
+
+  private void appendAndCount(final CharSequence csq) {
+    final int before = messages.length();
+    messages.append(csq);
+    final int after = messages.length();
+    totalCharacterCount += after - before;
+  }
+
+  private void checkAndCut() {
+    if (messages.length() > limit) {
+      final int newStart = messages.length() - limit;
+      messages.delete(0, newStart);
+    }
+  }
+
+  /**
+   * Get current length of messages considering truncates
+   * without header and ellipses.
+   *
+   * @return current length
+   */
+  public int length() {
+    return messages.length();
+  }
+
+  public int getLimit() {
+    return limit;
+  }
+
+  /**
+   * Get a string representation of the actual contents, displaying also a
+   * header and ellipses when there was a truncate.
+   *
+   * @return String representation of the {@link #messages}
+   */
+  @Override
+  public String toString() {
+    if (messages.length() < totalCharacterCount) {
+      return String.format(TRUNCATED_MESSAGES_TEMPLATE, messages.length(),
+          totalCharacterCount, messages.toString());
+    }
+
+    return messages.toString();
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestBoundedAppender.java

@@ -16,14 +16,13 @@
  * limitations under the License.
  */
 
-package org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt;
+package org.apache.hadoop.yarn.util;
 
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
 import static org.junit.Assert.assertEquals;
-import static org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttemptImpl.BoundedAppender;
 
 /**
  * Test class for {@link BoundedAppender}.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java

@@ -38,7 +38,6 @@ import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
 
 import javax.crypto.SecretKey;
 
-import com.google.common.base.Preconditions;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
@@ -110,6 +109,7 @@ import org.apache.hadoop.yarn.state.MultipleArcTransition;
 import org.apache.hadoop.yarn.state.SingleArcTransition;
 import org.apache.hadoop.yarn.state.StateMachine;
 import org.apache.hadoop.yarn.state.StateMachineFactory;
+import org.apache.hadoop.yarn.util.BoundedAppender;
 import org.apache.hadoop.yarn.webapp.util.WebAppUtils;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -1326,7 +1326,7 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
     // AFTER the initial saving on app-attempt-start
     // These fields can be visible from outside only after they are saved in
     // StateStore
-    BoundedAppender diags = new BoundedAppender(diagnostics.limit);
+    BoundedAppender diags = new BoundedAppender(diagnostics.getLimit());
 
     // don't leave the tracking URL pointing to a non-existent AM
     if (conf.getBoolean(YarnConfiguration.APPLICATION_HISTORY_ENABLED,
@@ -2295,114 +2295,4 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
     return Collections.EMPTY_SET;
   }
 
-  /**
-   * A {@link CharSequence} appender that considers its {@link #limit} as upper
-   * bound.
-   * <p>
-   * When {@link #limit} would be reached on append, past messages will be
-   * truncated from head, and a header telling the user about truncation will be
-   * prepended, with ellipses in between header and messages.
-   * <p>
-   * Note that header and ellipses are not counted against {@link #limit}.
-   * <p>
-   * An example:
-   *
-   * <pre>
-   * {@code
-   *   // At the beginning it's an empty string
-   *   final Appendable shortAppender = new BoundedAppender(80);
-   *   // The whole message fits into limit
-   *   shortAppender.append(
-   *       "message1 this is a very long message but fitting into limit\n");
-   *   // The first message is truncated, the second not
-   *   shortAppender.append("message2 this is shorter than the previous one\n");
-   *   // The first message is deleted, the second truncated, the third
-   *   // preserved
-   *   shortAppender.append("message3 this is even shorter message, maybe.\n");
-   *   // The first two are deleted, the third one truncated, the last preserved
-   *   shortAppender.append("message4 the shortest one, yet the greatest :)");
-   *   // Current contents are like this:
-   *   // Diagnostic messages truncated, showing last 80 chars out of 199:
-   *   // ...s is even shorter message, maybe.
-   *   // message4 the shortest one, yet the greatest :)
-   * }
-   * </pre>
-   * <p>
-   * Note that <tt>null</tt> values are {@link #append(CharSequence) append}ed
-   * just like in {@link StringBuilder#append(CharSequence) original
-   * implementation}.
-   * <p>
-   * Note that this class is not thread safe.
-   */
-  @VisibleForTesting
-  static class BoundedAppender {
-    @VisibleForTesting
-    static final String TRUNCATED_MESSAGES_TEMPLATE =
-        "Diagnostic messages truncated, showing last "
-            + "%d chars out of %d:%n...%s";
-
-    private final int limit;
-    private final StringBuilder messages = new StringBuilder();
-    private int totalCharacterCount = 0;
-
-    BoundedAppender(final int limit) {
-      Preconditions.checkArgument(limit > 0, "limit should be positive");
-
-      this.limit = limit;
-    }
-
-    /**
-     * Append a {@link CharSequence} considering {@link #limit}, truncating
-     * from the head of {@code csq} or {@link #messages} when necessary.
-     *
-     * @param csq the {@link CharSequence} to append
-     * @return this
-     */
-    BoundedAppender append(final CharSequence csq) {
-      appendAndCount(csq);
-      checkAndCut();
-
-      return this;
-    }
-
-    private void appendAndCount(final CharSequence csq) {
-      final int before = messages.length();
-      messages.append(csq);
-      final int after = messages.length();
-      totalCharacterCount += after - before;
-    }
-
-    private void checkAndCut() {
-      if (messages.length() > limit) {
-        final int newStart = messages.length() - limit;
-        messages.delete(0, newStart);
-      }
-    }
-
-    /**
-     * Get current length of messages considering truncates
-     * without header and ellipses.
-     *
-     * @return current length
-     */
-    int length() {
-      return messages.length();
-    }
-
-    /**
-     * Get a string representation of the actual contents, displaying also a
-     * header and ellipses when there was a truncate.
-     *
-     * @return String representation of the {@link #messages}
-     */
-    @Override
-    public String toString() {
-      if (messages.length() < totalCharacterCount) {
-        return String.format(TRUNCATED_MESSAGES_TEMPLATE, messages.length(),
-            totalCharacterCount, messages.toString());
-      }
-
-      return messages.toString();
-    }
-  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/TestRMAppAttemptImplDiagnostics.java

@@ -26,6 +26,7 @@ import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.event.Dispatcher;
 import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
+import org.apache.hadoop.yarn.util.BoundedAppender;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
@@ -86,7 +87,7 @@ public class TestRMAppAttemptImplDiagnostics {
     appAttempt.appendDiagnostics(beyondLimit);
 
     final String truncated = String.format(
-        RMAppAttemptImpl.BoundedAppender.TRUNCATED_MESSAGES_TEMPLATE, 1024,
+        BoundedAppender.TRUNCATED_MESSAGES_TEMPLATE, 1024,
         1025, beyondLimit.substring(1));
 
     assertEquals("messages beyond limit should be truncated", truncated,