001/*
002 * (C) Copyright 2006-2011 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Florent Guillaume
018 */
019
020package org.nuxeo.ecm.core.query.sql.model;
021
022import java.util.ArrayList;
023import java.util.Iterator;
024import java.util.List;
025
026/**
027 * An expression for an single operator with an arbitrary number of operands.
028 * <p>
029 * It extends {@link Predicate} but it's really not a real Predicate (some users of Predicate expect it to have lvalue
030 * and rvalue fields, which are null in this class).
031 *
032 * @author Florent Guillaume
033 */
034public class MultiExpression extends Predicate {
035
036    private static final long serialVersionUID = 1L;
037
038    public final List<Predicate> predicates;
039
040    public MultiExpression(Operator operator, List<Predicate> predicates) {
041        super(null, operator, null);
042        this.predicates = predicates;
043    }
044
045    /**
046     * Copy constructor.
047     *
048     * @since 10.3
049     */
050    public MultiExpression(MultiExpression other) {
051        this(other.operator, new ArrayList<>(other.predicates));
052    }
053
054    @Override
055    public void accept(IVisitor visitor) {
056        visitor.visitMultiExpression(this);
057    }
058
059    @Override
060    public String toString() {
061        if (predicates.isEmpty()) {
062            StringBuilder sb = new StringBuilder();
063            // this is not really valid NXQL but sufficient for debugging
064            sb.append(operator);
065            sb.append("()");
066            return sb.toString();
067        }
068        if (predicates.size() == 1) {
069            // here debugging loses the operator, but this shouldn't be an issue for semantics
070            return predicates.get(0).toString();
071        }
072        StringBuilder sb = new StringBuilder();
073        sb.append('(');
074        for (Iterator<Predicate> it = predicates.iterator(); it.hasNext();) {
075            Predicate predicate = it.next();
076            sb.append(predicate.toString());
077            if (it.hasNext()) {
078                sb.append(' ');
079                sb.append(operator);
080                sb.append(' ');
081            }
082        }
083        sb.append(')');
084        return sb.toString();
085    }
086
087    @Override
088    public boolean equals(Object other) {
089        if (other == this) {
090            return true;
091        }
092        if (other instanceof MultiExpression) {
093            return equals((MultiExpression) other);
094        }
095        return false;
096    }
097
098    protected boolean equals(MultiExpression other) {
099        return predicates.equals(other.predicates) && super.equals(other);
100    }
101
102    @Override
103    public int hashCode() {
104        return predicates.hashCode() + super.hashCode();
105    }
106
107}