/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.api.java.typeutils.runtime.record;
import java.util.Arrays;
import eu.stratosphere.api.common.typeutils.TypeComparatorFactory;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.configuration.IllegalConfigurationException;
import eu.stratosphere.types.Key;
import eu.stratosphere.types.Record;
/**
* A factory for a {@link TypeComparator} for {@link Record}. The comparator uses a subset of
* the fields for the comparison. That subset of fields (positions and types) is read from the
* supplied configuration.
*/
public class RecordComparatorFactory implements TypeComparatorFactory<Record> {
private static final String NUM_KEYS = "numkeys";
private static final String KEY_POS_PREFIX = "keypos.";
private static final String KEY_CLASS_PREFIX = "keyclass.";
private static final String KEY_SORT_DIRECTION_PREFIX = "key-direction.";
// --------------------------------------------------------------------------------------------
private int[] positions;
private Class<? extends Key<?>>[] types;
private boolean[] sortDirections;
// --------------------------------------------------------------------------------------------
public RecordComparatorFactory() {
// do nothing, allow to be configured via config
}
public RecordComparatorFactory(int[] positions, Class<? extends Key<?>>[] types) {
this(positions, types, null);
}
public RecordComparatorFactory(int[] positions, Class<? extends Key<?>>[] types, boolean[] sortDirections) {
if (positions == null || types == null) {
throw new NullPointerException();
}
if (positions.length != types.length) {
throw new IllegalArgumentException();
}
this.positions = positions;
this.types = types;
if (sortDirections == null) {
this.sortDirections = new boolean[positions.length];
Arrays.fill(this.sortDirections, true);
} else if (sortDirections.length != positions.length) {
throw new IllegalArgumentException();
} else {
this.sortDirections = sortDirections;
}
}
@Override
public void writeParametersToConfig(Configuration config) {
for (int i = 0; i < this.positions.length; i++) {
if (this.positions[i] < 0) {
throw new IllegalArgumentException("The key position " + i + " is invalid: " + this.positions[i]);
}
if (this.types[i] == null || !Key.class.isAssignableFrom(this.types[i])) {
throw new IllegalArgumentException("The key type " + i + " is null or not implenting the interface " +
Key.class.getName() + ".");
}
}
// write the config
config.setInteger(NUM_KEYS, this.positions.length);
for (int i = 0; i < this.positions.length; i++) {
config.setInteger(KEY_POS_PREFIX + i, this.positions[i]);
config.setString(KEY_CLASS_PREFIX + i, this.types[i].getName());
config.setBoolean(KEY_SORT_DIRECTION_PREFIX + i, this.sortDirections[i]);
}
}
@SuppressWarnings("unchecked")
@Override
public void readParametersFromConfig(Configuration config, ClassLoader cl) throws ClassNotFoundException {
// figure out how many key fields there are
final int numKeyFields = config.getInteger(NUM_KEYS, -1);
if (numKeyFields < 0) {
throw new IllegalConfigurationException("The number of keys for the comparator is invalid: " + numKeyFields);
}
final int[] positions = new int[numKeyFields];
final Class<? extends Key<?>>[] types = new Class[numKeyFields];
final boolean[] direction = new boolean[numKeyFields];
// read the individual key positions and types
for (int i = 0; i < numKeyFields; i++) {
// next key position
final int p = config.getInteger(KEY_POS_PREFIX + i, -1);
if (p >= 0) {
positions[i] = p;
} else {
throw new IllegalConfigurationException("Contained invalid position for key no positions for keys.");
}
// next key type
final String name = config.getString(KEY_CLASS_PREFIX + i, null);
if (name != null) {
types[i] = (Class<? extends Key<?>>) Class.forName(name, true, cl).asSubclass(Key.class);
} else {
throw new IllegalConfigurationException("The key type (" + i +
") for the comparator is null");
}
// next key sort direction
direction[i] = config.getBoolean(KEY_SORT_DIRECTION_PREFIX + i, true);
}
this.positions = positions;
this.types = types;
this.sortDirections = direction;
}
@Override
public RecordComparator createComparator() {
return new RecordComparator(this.positions, this.types, this.sortDirections);
}
}