/*
 * 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 static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.testclassification.FilterTests;
import org.apache.hadoop.hbase.testclassification.SmallTests;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.experimental.categories.Category;

/**
 * Tests for the page filter
 */
@Category({ FilterTests.class, SmallTests.class })
public class TestPageFilter {

  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
    HBaseClassTestRule.forClass(TestPageFilter.class);

  static final int ROW_LIMIT = 3;

  /**
   * test page size filter
   */
  @Test
  public void testPageSize() throws Exception {
    Filter f = new PageFilter(ROW_LIMIT);
    pageSizeTests(f);
  }

  /**
   * Test filter serialization
   */
  @Test
  public void testSerialization() throws Exception {
    Filter f = new PageFilter(ROW_LIMIT);
    // Decompose mainFilter to bytes.
    byte[] buffer = f.toByteArray();
    // Recompose mainFilter.
    Filter newFilter = PageFilter.parseFrom(buffer);

    // Ensure the serialization preserved the filter by running a full test.
    pageSizeTests(newFilter);
  }

  private void pageSizeTests(Filter f) throws Exception {
    testFiltersBeyondPageSize(f, ROW_LIMIT);
  }

  private void testFiltersBeyondPageSize(final Filter f, final int pageSize) throws IOException {
    int count = 0;
    for (int i = 0; i < (pageSize * 2); i++) {
      boolean filterOut = f.filterRow();

      if (filterOut) {
        break;
      } else {
        count++;
      }

      // If at last row, should tell us to skip all remaining
      if (count == pageSize) {
        assertTrue(f.filterAllRemaining());
      } else {
        assertFalse(f.filterAllRemaining());
      }

    }
    assertEquals(pageSize, count);
  }

}
