/*
* 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.solr.handler.component;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import org.apache.solr.common.params.FacetParams;
/**
* Emcapsulates a collection of {@link PivotFacetValue}s associated with a
* {@link PivotFacetField} withs pecial tracking of a {@link PivotFacetValue}
* corrisponding to the <code>null</code> value when {@link FacetParams#FACET_MISSING}
* is used.
*
* @see #markDirty
* @see PivotFacetField
* @see PivotFacetValue
*/
@SuppressWarnings("rawtypes")
public class PivotFacetFieldValueCollection implements Iterable<PivotFacetValue> {
private List<PivotFacetValue> explicitValues;
private PivotFacetValue missingValue;
private Map<Comparable, PivotFacetValue> valuesMap;
private boolean dirty = true;
//Facet parameters relating to this field
private final int facetFieldMinimumCount;
private final int facetFieldOffset;
private final int facetFieldLimit;
private final String facetFieldSort;
public PivotFacetFieldValueCollection(int minCount, int offset, int limit, String fieldSort){
this.explicitValues = new ArrayList<>();
this.valuesMap = new HashMap<>();
this.facetFieldMinimumCount = minCount;
this.facetFieldOffset = offset;
this.facetFieldLimit = limit;
this.facetFieldSort = fieldSort;
}
/**
* Indicates that the values in this collection have been modified by the caller.
*
* Any caller that manipulates the {@link PivotFacetValue}s contained in this collection
* must call this method after doing so.
*/
public void markDirty() {
dirty = true;
}
/**
* The {@link PivotFacetValue} with corisponding to a a value of
* <code>null</code> when {@link FacetParams#FACET_MISSING} is used.
*
* @return the appropriate <code>PivotFacetValue</code> object, may be null
* if we "missing" is not in use, or if it does not meat the mincount.
*/
public PivotFacetValue getMissingValue(){
return missingValue;
}
/**
* Read-Only access to the Collection of {@link PivotFacetValue}s corrisponding to
* non-missing values.
*
* @see #getMissingValue
*/
public List<PivotFacetValue> getExplicitValuesList() {
return Collections.unmodifiableList(explicitValues);
}
/**
* Size of {@link #getExplicitValuesList}
*/
public int getExplicitValuesListSize() {
return this.explicitValues.size();
}
/**
* Total number of {@link PivotFacetValue}s, including the "missing" value if used.
*
* @see #getMissingValue
* @see #getExplicitValuesList
*/
public int size() {
return this.getExplicitValuesListSize() + (this.missingValue == null ? 0 : 1);
}
/**
* Returns the appropriate sub-list of the explicit values that need to be refined,
* based on the {@link FacetParams#FACET_OFFSET} & {@link FacetParams#FACET_LIMIT}
* for this field.
*
* @see #getExplicitValuesList
* @see List#subList
*/
public List<PivotFacetValue> getNextLevelValuesToRefine() {
final int numRefinableValues = getExplicitValuesListSize();
if (facetFieldOffset < numRefinableValues) {
final int offsetPlusCount = (facetFieldLimit >= 0)
? Math.min(facetFieldLimit + facetFieldOffset, numRefinableValues)
: numRefinableValues;
return getExplicitValuesList().subList(facetFieldOffset, offsetPlusCount);
} else {
return Collections.<PivotFacetValue>emptyList();
}
}
/**
* Fast lookup to retrieve a {@link PivotFacetValue} from this collection if it
* exists
*
* @param value of the <code>PivotFacetValue</code> to lookup, if
* <code>null</code> this returns the same as {@link #getMissingValue}
* @return the corrisponding <code>PivotFacetValue</code> or null if there is
* no <code>PivotFacetValue</code> in this collection corrisponding to
* the specified value.
*/
public PivotFacetValue get(Comparable value){
return valuesMap.get(value);
}
/**
* Fetchs a {@link PivotFacetValue} from this collection via the index, may not
* be used to fetch the <code>PivotFacetValue</code> corrisponding to the missing-value.
*
* @see #getExplicitValuesList
* @see List#get(int)
* @see #getMissingValue
*/
public PivotFacetValue getAt(int index){
return explicitValues.get(index);
}
/**
* Adds a {@link PivotFacetValue} to this collection -- callers must not use this
* method if a {@link PivotFacetValue} with the same value already exists in this collection
*/
public void add(PivotFacetValue pfValue) {
Comparable val = pfValue.getValue();
assert ! this.valuesMap.containsKey(val)
: "Must not add duplicate PivotFacetValue with redundent inner value";
dirty = true;
if(null == val) {
this.missingValue = pfValue;
} else {
this.explicitValues.add(pfValue);
}
this.valuesMap.put(val, pfValue);
}
/**
* Destructive method that recursively prunes values from the data structure
* based on the counts for those values and the effective sort, mincount, limit,
* and offset being used for each field.
* <p>
* This method should only be called after all refinement is completed.
* </p>
*
* @see PivotFacetField#trim
* @see PivotFacet#getTrimmedPivotsAsListOfNamedLists
*/
public void trim() { // NOTE: destructive
// TODO: see comment in PivotFacetField about potential optimization
// (ie: trim as we refine)
trimNonNullValues();
trimNullValue();
}
private void trimNullValue(){
if (missingValue == null) {
return;
}
if (missingValue.getCount() >= facetFieldMinimumCount){
if (null != missingValue.getChildPivot()) {
missingValue.getChildPivot().trim();
}
} else { // missing count less than mincount
missingValue = null;
}
}
private void trimNonNullValues(){
if (explicitValues != null && explicitValues.size() > 0) {
sort();
ArrayList<PivotFacetValue> trimmedValues = new ArrayList<>();
int facetsSkipped = 0;
for (PivotFacetValue pivotValue : explicitValues) {
if (pivotValue.getCount() >= facetFieldMinimumCount) {
if (facetsSkipped >= facetFieldOffset) {
trimmedValues.add(pivotValue);
if (pivotValue.getChildPivot() != null) {
pivotValue.getChildPivot().trim();
}
if (facetFieldLimit > 0 && trimmedValues.size() >= facetFieldLimit) {
break;
}
} else {
facetsSkipped++;
}
}
}
explicitValues = trimmedValues;
valuesMap.clear();
}
}
/**
* Sorts the collection and recursively sorts the collections assocaited with
* any sub-pivots.
*
* @see FacetParams#FACET_SORT
* @see PivotFacetField#sort
*/
public void sort() {
if (dirty) {
if (facetFieldSort.equals(FacetParams.FACET_SORT_COUNT)) {
Collections.sort(this.explicitValues, new PivotFacetCountComparator());
} else if (facetFieldSort.equals(FacetParams.FACET_SORT_INDEX)) {
Collections.sort(this.explicitValues, new PivotFacetValueComparator());
}
dirty = false;
}
for (PivotFacetValue value : this.explicitValues)
if (value.getChildPivot() != null) {
value.getChildPivot().sort();
}
if (missingValue != null && missingValue.getChildPivot() != null) {
missingValue.getChildPivot().sort();
}
}
/**
* Iterator over all elements in this Collection, including the result of
* {@link #getMissingValue} as the last element (if it exists)
*/
@Override
public Iterator<PivotFacetValue> iterator() {
Iterator<PivotFacetValue> it = new Iterator<PivotFacetValue>() {
private final Iterator valuesIterator = explicitValues.iterator();
private boolean shouldGiveMissingValue = (missingValue != null);
@Override
public boolean hasNext() {
return valuesIterator.hasNext() || shouldGiveMissingValue;
}
@Override
public PivotFacetValue next() {
while(valuesIterator.hasNext()){
return (PivotFacetValue) valuesIterator.next();
}
//else
if(shouldGiveMissingValue){
shouldGiveMissingValue = false;
return missingValue;
}
return null;
}
@Override
public void remove() {
throw new UnsupportedOperationException("Can't remove from this iterator");
}
};
return it;
}
/** Sorts {@link PivotFacetValue} instances by their count */
public static class PivotFacetCountComparator implements Comparator<PivotFacetValue> {
public int compare(PivotFacetValue left, PivotFacetValue right) {
int countCmp = right.getCount() - left.getCount();
return (0 != countCmp) ? countCmp :
compareWithNullLast(left.getValue(), right.getValue());
}
}
/** Sorts {@link PivotFacetValue} instances by their value */
public static class PivotFacetValueComparator implements Comparator<PivotFacetValue> {
public int compare(PivotFacetValue left, PivotFacetValue right) {
return compareWithNullLast(left.getValue(), right.getValue());
}
}
/**
* A helper method for use in <code>Comparator</code> classes where object properties
* are <code>Comparable</code> but may be null.
*/
static int compareWithNullLast(final Comparable o1, final Comparable o2) {
if (null == o1) {
if (null == o2) {
return 0;
}
return 1; // o1 is null, o2 is not
}
if (null == o2) {
return -1; // o2 is null, o1 is not
}
return o1.compareTo(o2);
}
public String toString(){
return String.format(Locale.ROOT, "Values:%s | Missing:%s ", explicitValues, missingValue);
}
}