| /* |
| * 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.lucene.queries.function.valuesource; |
| |
| import org.apache.lucene.index.LeafReaderContext; |
| import org.apache.lucene.index.ReaderUtil; |
| import org.apache.lucene.queries.function.FunctionValues; |
| import org.apache.lucene.queries.function.ValueSource; |
| import org.apache.lucene.queries.function.docvalues.FloatDocValues; |
| import org.apache.lucene.search.IndexSearcher; |
| |
| import java.io.IOException; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Scales values to be between min and max. |
| * <p>This implementation currently traverses all of the source values to obtain |
| * their min and max. |
| * <p>This implementation currently cannot distinguish when documents have been |
| * deleted or documents that have no value, and 0.0 values will be used for |
| * these cases. This means that if values are normally all greater than 0.0, one can |
| * still end up with 0.0 as the min value to map from. In these cases, an |
| * appropriate map() function could be used as a workaround to change 0.0 |
| * to a value in the real range. |
| */ |
| public class ScaleFloatFunction extends ValueSource { |
| protected final ValueSource source; |
| protected final float min; |
| protected final float max; |
| |
| public ScaleFloatFunction(ValueSource source, float min, float max) { |
| this.source = source; |
| this.min = min; |
| this.max = max; |
| } |
| |
| @Override |
| public String description() { |
| return "scale(" + source.description() + "," + min + "," + max + ")"; |
| } |
| |
| private static class ScaleInfo { |
| float minVal; |
| float maxVal; |
| } |
| |
| private ScaleInfo createScaleInfo(Map context, LeafReaderContext readerContext) throws IOException { |
| final List<LeafReaderContext> leaves = ReaderUtil.getTopLevelContext(readerContext).leaves(); |
| |
| float minVal = Float.POSITIVE_INFINITY; |
| float maxVal = Float.NEGATIVE_INFINITY; |
| |
| for (LeafReaderContext leaf : leaves) { |
| int maxDoc = leaf.reader().maxDoc(); |
| FunctionValues vals = source.getValues(context, leaf); |
| for (int i=0; i<maxDoc; i++) { |
| if ( ! vals.exists(i) ) { |
| continue; |
| } |
| float val = vals.floatVal(i); |
| if ((Float.floatToRawIntBits(val) & (0xff<<23)) == 0xff<<23) { |
| // if the exponent in the float is all ones, then this is +Inf, -Inf or NaN |
| // which don't make sense to factor into the scale function |
| continue; |
| } |
| if (val < minVal) { |
| minVal = val; |
| } |
| if (val > maxVal) { |
| maxVal = val; |
| } |
| } |
| } |
| |
| if (minVal == Float.POSITIVE_INFINITY) { |
| // must have been an empty index |
| minVal = maxVal = 0; |
| } |
| |
| ScaleInfo scaleInfo = new ScaleInfo(); |
| scaleInfo.minVal = minVal; |
| scaleInfo.maxVal = maxVal; |
| context.put(ScaleFloatFunction.this, scaleInfo); |
| return scaleInfo; |
| } |
| |
| @Override |
| public FunctionValues getValues(Map context, LeafReaderContext readerContext) throws IOException { |
| |
| ScaleInfo scaleInfo = (ScaleInfo)context.get(ScaleFloatFunction.this); |
| if (scaleInfo == null) { |
| scaleInfo = createScaleInfo(context, readerContext); |
| } |
| |
| final float scale = (scaleInfo.maxVal-scaleInfo.minVal==0) ? 0 : (max-min)/(scaleInfo.maxVal-scaleInfo.minVal); |
| final float minSource = scaleInfo.minVal; |
| final float maxSource = scaleInfo.maxVal; |
| |
| final FunctionValues vals = source.getValues(context, readerContext); |
| |
| return new FloatDocValues(this) { |
| @Override |
| public boolean exists(int doc) throws IOException { |
| return vals.exists(doc); |
| } |
| @Override |
| public float floatVal(int doc) throws IOException { |
| return (vals.floatVal(doc) - minSource) * scale + min; |
| } |
| @Override |
| public String toString(int doc) throws IOException { |
| return "scale(" + vals.toString(doc) + ",toMin=" + min + ",toMax=" + max |
| + ",fromMin=" + minSource |
| + ",fromMax=" + maxSource |
| + ")"; |
| } |
| }; |
| } |
| |
| @Override |
| public void createWeight(Map context, IndexSearcher searcher) throws IOException { |
| source.createWeight(context, searcher); |
| } |
| |
| @Override |
| public int hashCode() { |
| int h = Float.floatToIntBits(min); |
| h = h*29; |
| h += Float.floatToIntBits(max); |
| h = h*29; |
| h += source.hashCode(); |
| return h; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (ScaleFloatFunction.class != o.getClass()) return false; |
| ScaleFloatFunction other = (ScaleFloatFunction)o; |
| return this.min == other.min |
| && this.max == other.max |
| && this.source.equals(other.source); |
| } |
| } |