+++ /dev/null
-package org.apache.lucene.search.spans;
-
-/**
- * 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.
- */
-
-import java.io.IOException;
-import java.lang.reflect.Method;
-
-import org.apache.lucene.index.IndexReader;
-import org.apache.lucene.index.Term;
-import org.apache.lucene.search.MultiTermQuery;
-import org.apache.lucene.search.Query;
-import org.apache.lucene.search.TopTermsRewrite;
-import org.apache.lucene.search.ScoringRewrite;
-import org.apache.lucene.search.BooleanClause.Occur; // javadocs only
-
-/**
- * Wraps any {@link MultiTermQuery} as a {@link SpanQuery},
- * so it can be nested within other SpanQuery classes.
- * <p>
- * The query is rewritten by default to a {@link SpanOrQuery} containing
- * the expanded terms, but this can be customized.
- * <p>
- * Example:
- * <blockquote><pre>
- * {@code
- * WildcardQuery wildcard = new WildcardQuery(new Term("field", "bro?n"));
- * SpanQuery spanWildcard = new SpanMultiTermQueryWrapper<WildcardQuery>(wildcard);
- * // do something with spanWildcard, such as use it in a SpanFirstQuery
- * }
- * </pre></blockquote>
- */
-public class SpanMultiTermQueryWrapper<Q extends MultiTermQuery> extends SpanQuery {
- protected final Q query;
- private Method getFieldMethod = null, getTermMethod = null;
-
- /**
- * Create a new SpanMultiTermQueryWrapper.
- *
- * @param query Query to wrap.
- * <p>
- * NOTE: This will call {@link MultiTermQuery#setRewriteMethod(MultiTermQuery.RewriteMethod)}
- * on the wrapped <code>query</code>, changing its rewrite method to a suitable one for spans.
- * Be sure to not change the rewrite method on the wrapped query afterwards! Doing so will
- * throw {@link UnsupportedOperationException} on rewriting this query!
- * In Lucene 3.x, MultiTermQuery allows queries to rewrite to different field names, but SpanQuery
- * needs a fixed field. The wrapped query must therefore support getField() or getTerm().
- * @throws IllegalArgumentException if the wrapped query does not provide getField() or getTerm().
- */
- public SpanMultiTermQueryWrapper(Q query) {
- this.query = query;
-
- MultiTermQuery.RewriteMethod method = query.getRewriteMethod();
- if (method instanceof TopTermsRewrite) {
- final int pqsize = ((TopTermsRewrite) method).getSize();
- setRewriteMethod(new TopTermsSpanBooleanQueryRewrite(pqsize));
- } else {
- setRewriteMethod(SCORING_SPAN_QUERY_REWRITE);
- }
-
- // In Lucene 3.x, MTQ has no fixed field, we need to get it by reflection.
- // If the underlying query does not allow to get a constant field, we throw IAE:
- try {
- getFieldMethod = query.getClass().getMethod("getField");
- } catch (Exception e1) {
- try {
- getTermMethod = query.getClass().getMethod("getTerm");
- } catch (Exception e2) {
- try {
- getTermMethod = query.getClass().getMethod("getPrefix");
- } catch (Exception e3) {
- throw new IllegalArgumentException("SpanMultiTermQueryWrapper can only wrap MultiTermQueries"+
- " that can return a field name using getField() or getTerm()");
- }
- }
- }
- }
-
- /**
- * Expert: returns the rewriteMethod
- */
- public final SpanRewriteMethod getRewriteMethod() {
- final MultiTermQuery.RewriteMethod m = query.getRewriteMethod();
- if (!(m instanceof SpanRewriteMethod))
- throw new UnsupportedOperationException("You can only use SpanMultiTermQueryWrapper with a suitable SpanRewriteMethod.");
- return (SpanRewriteMethod) m;
- }
-
- /**
- * Expert: sets the rewrite method. This only makes sense
- * to be a span rewrite method.
- */
- public final void setRewriteMethod(SpanRewriteMethod rewriteMethod) {
- query.setRewriteMethod(rewriteMethod);
- }
-
- @Override
- public Spans getSpans(IndexReader reader) throws IOException {
- throw new UnsupportedOperationException("Query should have been rewritten");
- }
-
- @Override
- public String getField() {
- try {
- if (getFieldMethod != null) {
- return (String) getFieldMethod.invoke(query);
- } else {
- assert getTermMethod != null;
- return ((Term) getTermMethod.invoke(query)).field();
- }
- } catch (Exception e) {
- throw new RuntimeException("Cannot invoke getField() or getTerm() on wrapped query.", e);
- }
- }
-
- @Override
- public String toString(String field) {
- StringBuilder builder = new StringBuilder();
- builder.append("SpanMultiTermQueryWrapper(");
- builder.append(query.toString(field));
- builder.append(")");
- return builder.toString();
- }
-
- @Override
- public Query rewrite(IndexReader reader) throws IOException {
- final Query q = query.rewrite(reader);
- if (!(q instanceof SpanQuery))
- throw new UnsupportedOperationException("You can only use SpanMultiTermQueryWrapper with a suitable SpanRewriteMethod.");
- return q;
- }
-
- @Override
- public int hashCode() {
- return 31 * query.hashCode();
- }
-
- @Override
- public boolean equals(Object obj) {
- if (this == obj) return true;
- if (obj == null) return false;
- if (getClass() != obj.getClass()) return false;
- final SpanMultiTermQueryWrapper other = (SpanMultiTermQueryWrapper) obj;
- return query.equals(other.query);
- }
-
- /** Abstract class that defines how the query is rewritten. */
- public static abstract class SpanRewriteMethod extends MultiTermQuery.RewriteMethod {
- @Override
- public abstract SpanQuery rewrite(IndexReader reader, MultiTermQuery query) throws IOException;
- }
-
- /**
- * A rewrite method that first translates each term into a SpanTermQuery in a
- * {@link Occur#SHOULD} clause in a BooleanQuery, and keeps the
- * scores as computed by the query.
- *
- * @see #setRewriteMethod
- */
- public final static SpanRewriteMethod SCORING_SPAN_QUERY_REWRITE = new SpanRewriteMethod() {
- private final ScoringRewrite<SpanOrQuery> delegate = new ScoringRewrite<SpanOrQuery>() {
- @Override
- protected SpanOrQuery getTopLevelQuery() {
- return new SpanOrQuery();
- }
-
- @Override
- protected void addClause(SpanOrQuery topLevel, Term term, float boost) {
- final SpanTermQuery q = new SpanTermQuery(term);
- q.setBoost(boost);
- topLevel.addClause(q);
- }
- };
-
- @Override
- public SpanQuery rewrite(IndexReader reader, MultiTermQuery query) throws IOException {
- return delegate.rewrite(reader, query);
- }
-
- // Make sure we are still a singleton even after deserializing
- protected Object readResolve() {
- return SCORING_SPAN_QUERY_REWRITE;
- }
- };
-
- /**
- * A rewrite method that first translates each term into a SpanTermQuery in a
- * {@link Occur#SHOULD} clause in a BooleanQuery, and keeps the
- * scores as computed by the query.
- *
- * <p>
- * This rewrite method only uses the top scoring terms so it will not overflow
- * the boolean max clause count.
- *
- * @see #setRewriteMethod
- */
- public static final class TopTermsSpanBooleanQueryRewrite extends SpanRewriteMethod {
- private final TopTermsRewrite<SpanOrQuery> delegate;
-
- /**
- * Create a TopTermsSpanBooleanQueryRewrite for
- * at most <code>size</code> terms.
- */
- public TopTermsSpanBooleanQueryRewrite(int size) {
- delegate = new TopTermsRewrite<SpanOrQuery>(size) {
- @Override
- protected int getMaxSize() {
- return Integer.MAX_VALUE;
- }
-
- @Override
- protected SpanOrQuery getTopLevelQuery() {
- return new SpanOrQuery();
- }
-
- @Override
- protected void addClause(SpanOrQuery topLevel, Term term, float boost) {
- final SpanTermQuery q = new SpanTermQuery(term);
- q.setBoost(boost);
- topLevel.addClause(q);
- }
- };
- }
-
- /** return the maximum priority queue size */
- public int getSize() {
- return delegate.getSize();
- }
-
- @Override
- public SpanQuery rewrite(IndexReader reader, MultiTermQuery query) throws IOException {
- return delegate.rewrite(reader, query);
- }
-
- @Override
- public int hashCode() {
- return 31 * delegate.hashCode();
- }
-
- @Override
- public boolean equals(Object obj) {
- if (this == obj) return true;
- if (obj == null) return false;
- if (getClass() != obj.getClass()) return false;
- final TopTermsSpanBooleanQueryRewrite other = (TopTermsSpanBooleanQueryRewrite) obj;
- return delegate.equals(other.delegate);
- }
-
- }
-
-}
fnp / pylucene.git / blobdiff