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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.prelude.query;
import java.util.Iterator;
import java.util.List;
/**
* Helper function for Item
* @author <a href="mailto:arnebef@yahoo-inc.com">Arne Bergene Fossaa</a>
*/
public class ItemHelper {
/*
We could have exchanged the following 3 functions with this
But this introspection is a bit too much of a hack, so we'll leave it with this.
public static <T extends CompositeItem> T ensureIsItem(Item unknown,Class<T> tClass) {
if(unknown != null && tClass.isInstance(unknown)) {
return (T) unknown;
}
T item;
try {
Constructor<T> n = tClass.getConstructor();
item = n.newInstance();
} catch (NoSuchMethodException e) {
return null;
} catch (InvocationTargetException e) {
return null;
} catch (IllegalAccessException e) {
return null;
} catch (InstantiationException e) {
return null;
}
if(item != null) {
item.addItem(unknown);
}
return item;
}
*/
/** Traverse the query tree and return total number of terms */
int getNumTerms(Item rootNode) {
int numTerms = 0;
if (rootNode == null) {
return 0;
} else if (rootNode instanceof CompositeItem) {
CompositeItem composite = (CompositeItem) rootNode;
for (Iterator<Item> i = composite.getItemIterator(); i.hasNext();) {
numTerms += getNumTerms(i.next());
}
} else if (rootNode instanceof TermItem) {
return 1;
} else {
return 0;
}
return numTerms;
}
public void getPositiveTerms(Item item, List<IndexedItem> terms) {
if (item instanceof NotItem) {
getPositiveTerms(((NotItem) item).getPositiveItem(), terms);
} else if (item instanceof PhraseItem) {
PhraseItem pItem = (PhraseItem)item;
terms.add(pItem);
} else if (item instanceof CompositeItem) {
for (Iterator<Item> i = ((CompositeItem) item).getItemIterator(); i.hasNext();) {
getPositiveTerms(i.next(), terms);
}
} else if (item instanceof TermItem) {
terms.add((TermItem)item);
}
}
}
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