src/org/apache/pig/impl/util/CastUtils.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.pig.impl.util;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pig.LoadCaster;
import org.apache.pig.PigWarning;
import org.apache.pig.ResourceSchema.ResourceFieldSchema;
import org.apache.pig.data.DataByteArray;
import org.apache.pig.data.DataType;

public class CastUtils {

	private static Integer mMaxInt = Integer.valueOf(Integer.MAX_VALUE);

	private static Long mMaxLong = Long.valueOf(Long.MAX_VALUE);

	protected static final Log mLog = LogFactory.getLog(CastUtils.class);

	/**
	 *
	 * @param caster LoadCaster to be used to convert the bytes into a field.
	 * @param bytes
	 * @param fieldSchema schema of Bag or Tuple; pass in null if a simple type.
	 * @param dataType type from DataType
	 * @return converted object.
	 * @throws IOException
	 */
	public static Object convertToType(LoadCaster caster, byte[] bytes,
	        ResourceFieldSchema fieldSchema, byte dataType) throws IOException {
	    switch (dataType) {
	    case (DataType.BAG): return caster.bytesToBag(bytes, fieldSchema);
	    case (DataType.BYTEARRAY): return new DataByteArray(bytes);
	    case (DataType.CHARARRAY): return caster.bytesToCharArray(bytes);
	    case (DataType.DOUBLE): return caster.bytesToDouble(bytes);
	    case (DataType.FLOAT): return caster.bytesToFloat(bytes);
	    case (DataType.INTEGER): return caster.bytesToInteger(bytes);
	    case (DataType.BIGINTEGER): return caster.bytesToBigInteger(bytes);
	    case (DataType.BIGDECIMAL): return caster.bytesToBigDecimal(bytes);
	    case (DataType.LONG): return caster.bytesToLong(bytes);
	    case (DataType.BOOLEAN): return caster.bytesToBoolean(bytes);
	    case (DataType.DATETIME): return caster.bytesToDateTime(bytes);
	    case (DataType.MAP): return caster.bytesToMap(bytes, fieldSchema);
	    case (DataType.TUPLE): return caster.bytesToTuple(bytes, fieldSchema);
	    default: throw new IOException("Unknown type " + dataType);
	    }
	}

	public static Double stringToDouble(String str) {
		if (str == null) {
			return null;
		} else {
			try {
				return Double.parseDouble(str);
			} catch (NumberFormatException e) {
				LogUtils
						.warn(
								CastUtils.class,
								"Unable to interpret value "
										+ str
										+ " in field being "
										+ "converted to double, caught NumberFormatException <"
										+ e.getMessage() + "> field discarded",
								PigWarning.FIELD_DISCARDED_TYPE_CONVERSION_FAILED,
								mLog);
				return null;
			}
		}
	}

	public static Float stringToFloat(String str) {
		if (str == null) {
			return null;
		} else {
			try {
				return Float.parseFloat(str);
			} catch (NumberFormatException e) {
				LogUtils
						.warn(
								CastUtils.class,
								"Unable to interpret value "
										+ str
										+ " in field being "
										+ "converted to float, caught NumberFormatException <"
										+ e.getMessage() + "> field discarded",
								PigWarning.FIELD_DISCARDED_TYPE_CONVERSION_FAILED,
								mLog);
				return null;
			}
		}
	}

	public static Integer stringToInteger(String str) {
		if (str == null) {
			return null;
		} else {
			try {
				return Integer.parseInt(str);
			} catch (NumberFormatException e) {
				// It's possible that this field can be interpreted as a double.
				// Unfortunately Java doesn't handle this in Integer.valueOf. So
				// we need to try to convert it to a double and if that works
				// then
				// go to an int.
				try {
					Double d = Double.valueOf(str);
					// Need to check for an overflow error
					if (d.doubleValue() > mMaxInt.doubleValue() + 1.0) {
						LogUtils.warn(CastUtils.class, "Value " + d
								+ " too large for integer",
								PigWarning.TOO_LARGE_FOR_INT, mLog);
						return null;
					}
					return Integer.valueOf(d.intValue());
				} catch (NumberFormatException nfe2) {
					LogUtils
							.warn(
									CastUtils.class,
									"Unable to interpret value "
											+ str
											+ " in field being "
											+ "converted to int, caught NumberFormatException <"
											+ e.getMessage()
											+ "> field discarded",
									PigWarning.FIELD_DISCARDED_TYPE_CONVERSION_FAILED,
									mLog);
					return null;
				}
			}
		}
	}

	public static Long stringToLong(String str) {
		if (str == null) {
			return null;
		} else {
			try {
				return Long.parseLong(str);
			} catch (NumberFormatException e) {
				// It's possible that this field can be interpreted as a double.
				// Unfortunately Java doesn't handle this in Long.valueOf. So
				// we need to try to convert it to a double and if that works
				// then
				// go to an long.
				try {
					Double d = Double.valueOf(str);
					// Need to check for an overflow error
					if (d.doubleValue() > mMaxLong.doubleValue() + 1.0) {
						LogUtils.warn(CastUtils.class, "Value " + d
								+ " too large for long",
								PigWarning.TOO_LARGE_FOR_INT, mLog);
						return null;
					}
					return Long.valueOf(d.longValue());
				} catch (NumberFormatException nfe2) {
					LogUtils
							.warn(
									CastUtils.class,
									"Unable to interpret value "
											+ str
											+ " in field being "
											+ "converted to long, caught NumberFormatException <"
											+ nfe2.getMessage()
											+ "> field discarded",
									PigWarning.FIELD_DISCARDED_TYPE_CONVERSION_FAILED,
									mLog);
					return null;
				}
			}
		}
	}

	public static Boolean stringToBoolean(String str) {
        if (str == null) {
            return null;
        } else {
            if (str.equalsIgnoreCase("true")) {
                return Boolean.TRUE;
            } else if (str.equalsIgnoreCase("false")) {
                return Boolean.FALSE;
            } else {
                return null;
            }
        }
    }

}