- * Allows multiple {@link Filter}s to be chained. - * Logical operations such as NOT and XOR - * are applied between filters. One operation can be used - * for all filters, or a specific operation can be declared - * for each filter. - *
- *- * Order in which filters are called depends on - * the position of the filter in the chain. It's probably - * more efficient to place the most restrictive filters - * /least computationally-intensive filters first. - *
- * - */ -public class ChainedFilter extends Filter -{ - public static final int OR = 0; - public static final int AND = 1; - public static final int ANDNOT = 2; - public static final int XOR = 3; - /** - * Logical operation when none is declared. Defaults to - * OR. - */ - public static int DEFAULT = OR; - - /** The filter chain */ - private Filter[] chain = null; - - private int[] logicArray; - - private int logic = -1; - - /** - * Ctor. - * @param chain The chain of filters - */ - public ChainedFilter(Filter[] chain) - { - this.chain = chain; - } - - /** - * Ctor. - * @param chain The chain of filters - * @param logicArray Logical operations to apply between filters - */ - public ChainedFilter(Filter[] chain, int[] logicArray) - { - this.chain = chain; - this.logicArray = logicArray; - } - - /** - * Ctor. - * @param chain The chain of filters - * @param logic Logical operation to apply to ALL filters - */ - public ChainedFilter(Filter[] chain, int logic) - { - this.chain = chain; - this.logic = logic; - } - - /** - * {@link Filter#getDocIdSet}. - */ - @Override - public DocIdSet getDocIdSet(IndexReader reader) throws IOException - { - int[] index = new int[1]; // use array as reference to modifiable int; - index[0] = 0; // an object attribute would not be thread safe. - if (logic != -1) - return getDocIdSet(reader, logic, index); - else if (logicArray != null) - return getDocIdSet(reader, logicArray, index); - else - return getDocIdSet(reader, DEFAULT, index); - } - - private DocIdSetIterator getDISI(Filter filter, IndexReader reader) - throws IOException { - DocIdSet docIdSet = filter.getDocIdSet(reader); - if (docIdSet == null) { - return DocIdSet.EMPTY_DOCIDSET.iterator(); - } else { - DocIdSetIterator iter = docIdSet.iterator(); - if (iter == null) { - return DocIdSet.EMPTY_DOCIDSET.iterator(); - } else { - return iter; - } - } - } - - private OpenBitSetDISI initialResult(IndexReader reader, int logic, int[] index) - throws IOException - { - OpenBitSetDISI result; - /** - * First AND operation takes place against a completely false - * bitset and will always return zero results. - */ - if (logic == AND) - { - result = new OpenBitSetDISI(getDISI(chain[index[0]], reader), reader.maxDoc()); - ++index[0]; - } - else if (logic == ANDNOT) - { - result = new OpenBitSetDISI(getDISI(chain[index[0]], reader), reader.maxDoc()); - result.flip(0,reader.maxDoc()); // NOTE: may set bits for deleted docs. - ++index[0]; - } - else - { - result = new OpenBitSetDISI(reader.maxDoc()); - } - return result; - } - - /** Provide a SortedVIntList when it is definitely - * smaller than an OpenBitSet - * @deprecated Either use CachingWrapperFilter, or - * switch to a different DocIdSet implementation yourself. - * This method will be removed in Lucene 4.0 - **/ - @Deprecated - protected final DocIdSet finalResult(OpenBitSetDISI result, int maxDocs) { - return result; - } - - - /** - * Delegates to each filter in the chain. - * @param reader IndexReader - * @param logic Logical operation - * @return DocIdSet - */ - private DocIdSet getDocIdSet(IndexReader reader, int logic, int[] index) - throws IOException - { - OpenBitSetDISI result = initialResult(reader, logic, index); - for (; index[0] < chain.length; index[0]++) - { - doChain(result, logic, chain[index[0]].getDocIdSet(reader)); - } - return finalResult(result, reader.maxDoc()); - } - - /** - * Delegates to each filter in the chain. - * @param reader IndexReader - * @param logic Logical operation - * @return DocIdSet - */ - private DocIdSet getDocIdSet(IndexReader reader, int[] logic, int[] index) - throws IOException - { - if (logic.length != chain.length) - throw new IllegalArgumentException("Invalid number of elements in logic array"); - - OpenBitSetDISI result = initialResult(reader, logic[0], index); - for (; index[0] < chain.length; index[0]++) - { - doChain(result, logic[index[0]], chain[index[0]].getDocIdSet(reader)); - } - return finalResult(result, reader.maxDoc()); - } - - @Override - public String toString() - { - StringBuilder sb = new StringBuilder(); - sb.append("ChainedFilter: ["); - for (int i = 0; i < chain.length; i++) - { - sb.append(chain[i]); - sb.append(' '); - } - sb.append(']'); - return sb.toString(); - } - - private void doChain(OpenBitSetDISI result, int logic, DocIdSet dis) - throws IOException { - - if (dis instanceof OpenBitSet) { - // optimized case for OpenBitSets - switch (logic) { - case OR: - result.or((OpenBitSet) dis); - break; - case AND: - result.and((OpenBitSet) dis); - break; - case ANDNOT: - result.andNot((OpenBitSet) dis); - break; - case XOR: - result.xor((OpenBitSet) dis); - break; - default: - doChain(result, DEFAULT, dis); - break; - } - } else { - DocIdSetIterator disi; - if (dis == null) { - disi = DocIdSet.EMPTY_DOCIDSET.iterator(); - } else { - disi = dis.iterator(); - if (disi == null) { - disi = DocIdSet.EMPTY_DOCIDSET.iterator(); - } - } - - switch (logic) { - case OR: - result.inPlaceOr(disi); - break; - case AND: - result.inPlaceAnd(disi); - break; - case ANDNOT: - result.inPlaceNot(disi); - break; - case XOR: - result.inPlaceXor(disi); - break; - default: - doChain(result, DEFAULT, dis); - break; - } - } - } - -}