Subversion Repositories SmartDukaan

/*

 * 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.thrift;

import java.io.ByteArrayInputStream;

import java.io.UnsupportedEncodingException;

import org.apache.thrift.protocol.TBinaryProtocol;

import org.apache.thrift.protocol.TField;

import org.apache.thrift.protocol.TProtocol;

import org.apache.thrift.protocol.TProtocolFactory;

import org.apache.thrift.protocol.TProtocolUtil;

import org.apache.thrift.protocol.TType;

import org.apache.thrift.transport.TIOStreamTransport;

import org.apache.thrift.TFieldIdEnum;

/**

 * Generic utility for easily deserializing objects from a byte array or Java

 * String.

 *

 */

public class TDeserializer {

  private final TProtocolFactory protocolFactory_;

  /**

   * Create a new TDeserializer that uses the TBinaryProtocol by default.

   */

  public TDeserializer() {

    this(new TBinaryProtocol.Factory());

  }

  /**

   * Create a new TDeserializer. It will use the TProtocol specified by the

   * factory that is passed in.

   *

   * @param protocolFactory Factory to create a protocol

   */

  public TDeserializer(TProtocolFactory protocolFactory) {

    protocolFactory_ = protocolFactory;

  }

  /**

   * Deserialize the Thrift object from a byte array.

   *

   * @param base The object to read into

   * @param bytes The array to read from

   */

  public void deserialize(TBase base, byte[] bytes) throws TException {

    base.read(

        protocolFactory_.getProtocol(

          new TIOStreamTransport(

            new ByteArrayInputStream(bytes))));

  }

  /**

   * Deserialize the Thrift object from a Java string, using a specified

   * character set for decoding.

   *

   * @param base The object to read into

   * @param data The string to read from

   * @param charset Valid JVM charset

   */

  public void deserialize(TBase base, String data, String charset) throws TException {

    try {

      deserialize(base, data.getBytes(charset));

    } catch (UnsupportedEncodingException uex) {

      throw new TException("JVM DOES NOT SUPPORT ENCODING: " + charset);

    }

  }

  /**

   * Deserialize only a single Thrift object (addressed by recursively using field id)

   * from a byte record.

   * @param record The object to read from

   * @param tb The object to read into

   * @param fieldIdPath The FieldId's that define a path tb

   * @throws TException 

   */

  public void partialDeserialize(TBase tb, byte[] bytes, TFieldIdEnum ... fieldIdPath) throws TException {

    // if there are no elements in the path, then the user is looking for the 

    // regular deserialize method

    // TODO: it might be nice not to have to do this check every time to save

    // some performance.

    if (fieldIdPath.length == 0) {

      deserialize(tb, bytes);

      return;

    }

    TProtocol iprot = protocolFactory_.getProtocol(

        new TIOStreamTransport(

          new ByteArrayInputStream(bytes))); 

    // index into field ID path being currently searched for

    int curPathIndex = 0;

    iprot.readStructBegin();

    while (curPathIndex < fieldIdPath.length) {

      TField field = iprot.readFieldBegin();

      // we can stop searching if we either see a stop or we go past the field 

      // id we're looking for (since fields should now be serialized in asc

      // order).

      if (field.type == TType.STOP || field.id > fieldIdPath[curPathIndex].getThriftFieldId()) { 

        return;

      }

      if (field.id != fieldIdPath[curPathIndex].getThriftFieldId()) {

        // Not the field we're looking for. Skip field.

        TProtocolUtil.skip(iprot, field.type);

        iprot.readFieldEnd();

      } else {

        // This field is the next step in the path. Step into field.

        curPathIndex++;

        if (curPathIndex < fieldIdPath.length) {

          iprot.readStructBegin();

        }

      }

    }

    // when this line is reached, iprot will be positioned at the start of tb.

    tb.read(iprot);

  }

  /**

   * Deserialize the Thrift object from a Java string, using the default JVM

   * charset encoding.

   *

   * @param base The object to read into

   * @param data The string to read from

   */

  public void toString(TBase base, String data) throws TException {

    deserialize(base, data.getBytes());

  }

}