HBASE-19683 Remove Superfluous Methods From String Class (BELUGA BEHR).

* Remove isEmpty method
* Remove repeat
Use the Apache Commons implementations instead.

hbase-client/src/main/java/org/apache/hadoop/hbase/client/replication/ReplicationPeerConfigUtil.java

@@ -39,7 +39,6 @@ import org.apache.hadoop.hbase.replication.ReplicationPeerConfig;
 import org.apache.hadoop.hbase.replication.ReplicationPeerConfigBuilder;
 import org.apache.hadoop.hbase.replication.ReplicationPeerDescription;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.Strings;
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.yetus.audience.InterfaceStability;
 import org.slf4j.Logger;
@@ -164,7 +163,7 @@ public final class ReplicationPeerConfigUtil {
     for (int i = 0, n = tableCFs.length; i < n; i++) {
       ReplicationProtos.TableCF tableCF = tableCFs[i];
       String namespace = tableCF.getTableName().getNamespace().toStringUtf8();
-      if (!Strings.isEmpty(namespace)) {
+      if (StringUtils.isNotEmpty(namespace)) {
         sb.append(namespace).append(".").
             append(tableCF.getTableName().getQualifier().toStringUtf8())
             .append(":");

hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaFilter.java

@@ -20,8 +20,8 @@ package org.apache.hadoop.hbase.quotas;
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.commons.lang3.StringUtils;
 import org.apache.yetus.audience.InterfaceAudience;
-import org.apache.hadoop.hbase.util.Strings;
 
 /**
  * Filter to use to filter the QuotaRetriever results.
@@ -44,7 +44,7 @@ public class QuotaFilter {
    */
   public QuotaFilter setUserFilter(final String regex) {
     this.userRegex = regex;
-    hasFilters |= !Strings.isEmpty(regex);
+    hasFilters |= StringUtils.isNotEmpty(regex);
     return this;
   }
 
@@ -55,7 +55,7 @@ public class QuotaFilter {
    */
   public QuotaFilter setTableFilter(final String regex) {
     this.tableRegex = regex;
-    hasFilters |= !Strings.isEmpty(regex);
+    hasFilters |= StringUtils.isNotEmpty(regex);
     return this;
   }
 
@@ -66,7 +66,7 @@ public class QuotaFilter {
    */
   public QuotaFilter setNamespaceFilter(final String regex) {
     this.namespaceRegex = regex;
-    hasFilters |= !Strings.isEmpty(regex);
+    hasFilters |= StringUtils.isNotEmpty(regex);
     return this;
   }
 

hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaTableUtil.java

@@ -28,6 +28,7 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.regex.Pattern;
 
+import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellScanner;
 import org.apache.hadoop.hbase.CompareOperator;
@@ -69,7 +70,6 @@ import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos.GetSpaceQuo
 import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos.Quotas;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.QuotaProtos.SpaceQuota;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.Strings;
 
 /**
  * Helper class to interact with the quota table.
@@ -191,11 +191,11 @@ public class QuotaTableUtil {
    */
   public static Filter makeFilter(final QuotaFilter filter) {
     FilterList filterList = new FilterList(FilterList.Operator.MUST_PASS_ALL);
-    if (!Strings.isEmpty(filter.getUserFilter())) {
+    if (StringUtils.isNotEmpty(filter.getUserFilter())) {
       FilterList userFilters = new FilterList(FilterList.Operator.MUST_PASS_ONE);
       boolean hasFilter = false;
 
-      if (!Strings.isEmpty(filter.getNamespaceFilter())) {
+      if (StringUtils.isNotEmpty(filter.getNamespaceFilter())) {
         FilterList nsFilters = new FilterList(FilterList.Operator.MUST_PASS_ALL);
         nsFilters.addFilter(new RowFilter(CompareOperator.EQUAL,
             new RegexStringComparator(getUserRowKeyRegex(filter.getUserFilter()), 0)));
@@ -205,7 +205,7 @@ public class QuotaTableUtil {
         userFilters.addFilter(nsFilters);
         hasFilter = true;
       }
-      if (!Strings.isEmpty(filter.getTableFilter())) {
+      if (StringUtils.isNotEmpty(filter.getTableFilter())) {
         FilterList tableFilters = new FilterList(FilterList.Operator.MUST_PASS_ALL);
         tableFilters.addFilter(new RowFilter(CompareOperator.EQUAL,
             new RegexStringComparator(getUserRowKeyRegex(filter.getUserFilter()), 0)));
@@ -221,10 +221,10 @@ public class QuotaTableUtil {
       }
 
       filterList.addFilter(userFilters);
-    } else if (!Strings.isEmpty(filter.getTableFilter())) {
+    } else if (StringUtils.isNotEmpty(filter.getTableFilter())) {
       filterList.addFilter(new RowFilter(CompareOperator.EQUAL,
           new RegexStringComparator(getTableRowKeyRegex(filter.getTableFilter()), 0)));
-    } else if (!Strings.isEmpty(filter.getNamespaceFilter())) {
+    } else if (StringUtils.isNotEmpty(filter.getNamespaceFilter())) {
       filterList.addFilter(new RowFilter(CompareOperator.EQUAL,
           new RegexStringComparator(getNamespaceRowKeyRegex(filter.getNamespaceFilter()), 0)));
     }

hbase-common/src/main/java/org/apache/hadoop/hbase/KeyValueTestUtil.java

@@ -23,6 +23,7 @@ import java.util.Collection;
 import java.util.List;
 
 import org.apache.commons.collections4.IterableUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.Strings;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -152,10 +153,10 @@ public class KeyValueTestUtil {
     int spacesAfterQualifier = maxQualifierLength - getQualifierString(kv).length() + 1;
     int spacesAfterTimestamp = maxTimestampLength
         - Long.valueOf(kv.getTimestamp()).toString().length() + 1;
-    return leadingLengths + getRowString(kv) + Strings.repeat(' ', spacesAfterRow)
-        + familyLength + getFamilyString(kv) + Strings.repeat(' ', spacesAfterFamily)
-        + getQualifierString(kv) + Strings.repeat(' ', spacesAfterQualifier)
-        + getTimestampString(kv) + Strings.repeat(' ', spacesAfterTimestamp)
+    return leadingLengths + getRowString(kv) + StringUtils.repeat(' ', spacesAfterRow)
+        + familyLength + getFamilyString(kv) + StringUtils.repeat(' ', spacesAfterFamily)
+        + getQualifierString(kv) + StringUtils.repeat(' ', spacesAfterQualifier)
+        + getTimestampString(kv) + StringUtils.repeat(' ', spacesAfterTimestamp)
         + getTypeString(kv) + " " + getValueString(kv);
   }
 

hbase-common/src/main/java/org/apache/hadoop/hbase/util/Strings.java

@@ -18,6 +18,7 @@
  */
 package org.apache.hadoop.hbase.util;
 
+import org.apache.commons.lang3.StringUtils;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
@@ -75,15 +76,6 @@ public class Strings {
     return dnPtr.endsWith(".") ? dnPtr.substring(0, dnPtr.length()-1) : dnPtr;
   }
 
-  /**
-   * Null-safe length check.
-   * @param input
-   * @return true if null or length==0
-   */
-  public static boolean isEmpty(String input) {
-    return input == null || input.length() == 0;
-  }
-
   /**
    * Push the input string to the right by appending a character before it, usually a space.
    * @param input the string to pad
@@ -96,19 +88,6 @@ public class Strings {
       throw new IllegalArgumentException("input \"" + input + "\" longer than maxLength=" + length);
     }
     int numPaddingCharacters = length - input.length();
-    return repeat(padding, numPaddingCharacters) + input;
-  }
-
-  /**
-   * @param c repeat this character
-   * @param reapeatFor the length of the output String
-   * @return c, repeated repeatFor times
-   */
-  public static String repeat(char c, int reapeatFor) {
-    StringBuilder sb = new StringBuilder();
-    for (int i = 0; i < reapeatFor; ++i) {
-      sb.append(c);
-    }
-    return sb.toString();
+    return StringUtils.repeat(padding, numPaddingCharacters) + input;
   }
 }