OperationOutput.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.hadoop.fs.slive;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.util.StringUtils;
/**
* An operation output has the following object format whereby simple types are
* represented as a key of dataType:operationType*measurementType and these
* simple types can be combined (mainly in the reducer) using there given types
* into a single operation output.
*
* Combination is done based on the data types and the following convention is
* followed (in the following order). If one is a string then the other will be
* concated as a string with a ";" separator. If one is a double then the other
* will be added as a double and the output will be a double. If one is a float
* then the other will be added as a float and the the output will be a float.
* Following this if one is a long the other will be added as a long and the
* output type will be a long and if one is a integer the other will be added as
* a integer and the output type will be an integer.
*/
class OperationOutput {
private OutputType dataType;
private String opType, measurementType;
private Object value;
private static final String TYPE_SEP = ":";
private static final String MEASUREMENT_SEP = "*";
private static final String STRING_SEP = ";";
enum OutputType {
STRING, FLOAT, LONG, DOUBLE, INTEGER
}
/**
* Parses a given key according to the expected key format and forms the given
* segments.
*
* @param key
* the key in expected dataType:operationType*measurementType format
* @param value
* a generic value expected to match the output type
* @throws IllegalArgumentException
* if invalid format
*/
OperationOutput(String key, Object value) {
int place = key.indexOf(TYPE_SEP);
if (place == -1) {
throw new IllegalArgumentException(
"Invalid key format - no type separator - " + TYPE_SEP);
}
try {
dataType = OutputType.valueOf(
StringUtils.toUpperCase(key.substring(0, place)));
} catch (Exception e) {
throw new IllegalArgumentException(
"Invalid key format - invalid output type", e);
}
key = key.substring(place + 1);
place = key.indexOf(MEASUREMENT_SEP);
if (place == -1) {
throw new IllegalArgumentException(
"Invalid key format - no measurement separator - " + MEASUREMENT_SEP);
}
opType = key.substring(0, place);
measurementType = key.substring(place + 1);
this.value = value;
}
OperationOutput(Text key, Object value) {
this(key.toString(), value);
}
public String toString() {
return getKeyString() + " (" + this.value + ")";
}
OperationOutput(OutputType dataType, String opType, String measurementType,
Object value) {
this.dataType = dataType;
this.opType = opType;
this.measurementType = measurementType;
this.value = value;
}
/**
* Merges according to the documented rules for merging. Only will merge if
* measurement type and operation type is the same.
*
* @param o1
* the first object to merge with the second
* @param o2
* the second object.
*
* @return OperationOutput merged output.
*
* @throws IllegalArgumentException
* if unable to merge due to incompatible formats/types
*/
static OperationOutput merge(OperationOutput o1, OperationOutput o2) {
if (o1.getMeasurementType().equals(o2.getMeasurementType())
&& o1.getOperationType().equals(o2.getOperationType())) {
Object newvalue = null;
OutputType newtype = null;
String opType = o1.getOperationType();
String mType = o1.getMeasurementType();
if (o1.getOutputType() == OutputType.STRING
|| o2.getOutputType() == OutputType.STRING) {
newtype = OutputType.STRING;
StringBuilder str = new StringBuilder();
str.append(o1.getValue());
str.append(STRING_SEP);
str.append(o2.getValue());
newvalue = str.toString();
} else if (o1.getOutputType() == OutputType.DOUBLE
|| o2.getOutputType() == OutputType.DOUBLE) {
newtype = OutputType.DOUBLE;
try {
newvalue = Double.parseDouble(o1.getValue().toString())
+ Double.parseDouble(o2.getValue().toString());
} catch (NumberFormatException e) {
throw new IllegalArgumentException(
"Unable to combine a type with a double " + o1 + " & " + o2, e);
}
} else if (o1.getOutputType() == OutputType.FLOAT
|| o2.getOutputType() == OutputType.FLOAT) {
newtype = OutputType.FLOAT;
try {
newvalue = Float.parseFloat(o1.getValue().toString())
+ Float.parseFloat(o2.getValue().toString());
} catch (NumberFormatException e) {
throw new IllegalArgumentException(
"Unable to combine a type with a float " + o1 + " & " + o2, e);
}
} else if (o1.getOutputType() == OutputType.LONG
|| o2.getOutputType() == OutputType.LONG) {
newtype = OutputType.LONG;
try {
newvalue = Long.parseLong(o1.getValue().toString())
+ Long.parseLong(o2.getValue().toString());
} catch (NumberFormatException e) {
throw new IllegalArgumentException(
"Unable to combine a type with a long " + o1 + " & " + o2, e);
}
} else if (o1.getOutputType() == OutputType.INTEGER
|| o2.getOutputType() == OutputType.INTEGER) {
newtype = OutputType.INTEGER;
try {
newvalue = Integer.parseInt(o1.getValue().toString())
+ Integer.parseInt(o2.getValue().toString());
} catch (NumberFormatException e) {
throw new IllegalArgumentException(
"Unable to combine a type with an int " + o1 + " & " + o2, e);
}
}
return new OperationOutput(newtype, opType, mType, newvalue);
} else {
throw new IllegalArgumentException("Unable to combine dissimilar types "
+ o1 + " & " + o2);
}
}
/**
* Formats the key for output
*
* @return String
*/
private String getKeyString() {
StringBuilder str = new StringBuilder();
str.append(getOutputType().name());
str.append(TYPE_SEP);
str.append(getOperationType());
str.append(MEASUREMENT_SEP);
str.append(getMeasurementType());
return str.toString();
}
/**
* Retrieves the key in a hadoop text object
*
* @return Text text output
*/
Text getKey() {
return new Text(getKeyString());
}
/**
* Gets the output value in text format
*
* @return Text
*/
Text getOutputValue() {
StringBuilder valueStr = new StringBuilder();
valueStr.append(getValue());
return new Text(valueStr.toString());
}
/**
* Gets the object that represents this value (expected to match the output
* data type)
*
* @return Object
*/
Object getValue() {
return value;
}
/**
* Gets the output data type of this class.
*/
OutputType getOutputType() {
return dataType;
}
/**
* Gets the operation type this object represents.
*
* @return String
*/
String getOperationType() {
return opType;
}
/**
* Gets the measurement type this object represents.
*
* @return String
*/
String getMeasurementType() {
return measurementType;
}
}