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package org.apache.lucene.search;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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/** A clause in a BooleanQuery. */
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public class BooleanClause implements java.io.Serializable {
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/** Specifies how clauses are to occur in matching documents. */
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public static enum Occur {
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/** Use this operator for clauses that <i>must</i> appear in the matching documents. */
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MUST { @Override public String toString() { return "+"; } },
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/** Use this operator for clauses that <i>should</i> appear in the
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* matching documents. For a BooleanQuery with no <code>MUST</code>
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* clauses one or more <code>SHOULD</code> clauses must match a document
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* for the BooleanQuery to match.
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* @see BooleanQuery#setMinimumNumberShouldMatch
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SHOULD { @Override public String toString() { return ""; } },
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/** Use this operator for clauses that <i>must not</i> appear in the matching documents.
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* Note that it is not possible to search for queries that only consist
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* of a <code>MUST_NOT</code> clause. */
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MUST_NOT { @Override public String toString() { return "-"; } };
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/** The query whose matching documents are combined by the boolean query.
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/** Constructs a BooleanClause.
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public BooleanClause(Query query, Occur occur) {
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public Occur getOccur() {
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public void setOccur(Occur occur) {
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public Query getQuery() {
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public void setQuery(Query query) {
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public boolean isProhibited() {
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return Occur.MUST_NOT == occur;
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public boolean isRequired() {
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return Occur.MUST == occur;
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/** Returns true if <code>o</code> is equal to this. */
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public boolean equals(Object o) {
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if (o == null || !(o instanceof BooleanClause))
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BooleanClause other = (BooleanClause)o;
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return this.query.equals(other.query)
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&& this.occur == other.occur;
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/** Returns a hash code value for this object.*/
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public int hashCode() {
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return query.hashCode() ^ (Occur.MUST == occur?1:0) ^ (Occur.MUST_NOT == occur?2:0);
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public String toString() {
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return occur.toString() + query.toString();