HBASE-2220 Add a binary comparator that only compares up to the length of the supplied byte array

git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@909590 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/hadoop/hbase/filter/BinaryPrefixComparator.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2009 The Apache Software Foundation
+ *
+ * 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.hbase.filter;
+
+import org.apache.hadoop.hbase.util.Bytes;
+
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
+
+/**
+ * A comparator which compares against a specified byte array, but only compares
+ * up to the length of this byte array. For the rest it is similar to
+ * {@link BinaryComparator}.
+ */ 
+public class BinaryPrefixComparator implements WritableByteArrayComparable {
+  private byte [] value;
+
+  /**
+   *  Writable constructor, do not use.
+   */
+  public BinaryPrefixComparator() {
+  }
+
+  /**
+   * Constructor.
+   * @param value the value to compare against
+   */
+  public BinaryPrefixComparator(byte [] value) {
+    this.value = value;
+  }
+
+  @Override
+  public void readFields(DataInput in) throws IOException {
+    value = Bytes.readByteArray(in);
+  }
+
+  @Override
+  public void write(DataOutput out) throws IOException {
+    Bytes.writeByteArray(out, value);
+  }
+
+  @Override
+  public int compareTo(byte [] value) {
+    return Bytes.compareTo(this.value, 0, this.value.length, value, 0, this.value.length);
+  }
+
+}