ParsingEncoder.java

/**
 * 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.avro.io;

import java.io.IOException;
import java.util.Arrays;

import org.apache.avro.AvroTypeException;

/** Base class for <a href="parsing/package-summary.html">parser</a>-based
 * {@link Encoder}s. */
public abstract class ParsingEncoder extends Encoder {
  /**
   * Tracks the number of items that remain to be written in
   * the collections (array or map).
   */
  private long[] counts = new long[10];

  protected int pos = -1;

  @Override
  public void setItemCount(long itemCount) throws IOException {
    if (counts[pos] != 0) {
      throw new AvroTypeException("Incorrect number of items written. " +
          counts[pos] + " more required.");
    }
    counts[pos] = itemCount;
  }

  @Override
  public void startItem() throws IOException {
    counts[pos]--;
  }

  /** Push a new collection on to the stack. */
  protected final void push() {
    if (++pos == counts.length) {
      counts = Arrays.copyOf(counts, pos + 10);
    }
    counts[pos] = 0;
  }

  protected final void pop() {
    if (counts[pos] != 0) {
      throw new AvroTypeException("Incorrect number of items written. " +
          counts[pos] + " more required.");
    }
    pos--;
  }

  protected final int depth() {
    return pos;
  }
}