com.blazebit.persistence.impl.JoinNodeGathererVisitor Maven / Gradle / Ivy

/*
 * Copyright 2014 - 2020 Blazebit.
 *
 * Licensed 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.
 */

package com.blazebit.persistence.impl;

import com.blazebit.persistence.parser.expression.PathExpression;
import com.blazebit.persistence.parser.expression.VisitorAdapter;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 *
 * @author Christian Beikov
 * @since 1.3.0
 */
public class JoinNodeGathererVisitor extends VisitorAdapter {

    private Collection joinNodes;

    public JoinNodeGathererVisitor() {
    }

    public JoinNodeGathererVisitor(Collection joinNodes) {
        this.joinNodes = joinNodes;
    }

    public Set collectNonRootJoinNodes(ResolvedExpression[] identifierExpressions) {
        joinNodes = new ArrayList<>();
        int size = identifierExpressions.length;
        for (int i = 0; i < size; i++) {
            identifierExpressions[i].getExpression().accept(this);
        }

        Set nonRootJoinNodeClosure = new HashSet<>();
        List nodes = (List) joinNodes;
        size = nodes.size();
        for (int i = 0; i < size; i++) {
            JoinNode n = nodes.get(i);
            if (n.getParent() != null) {
                nonRootJoinNodeClosure.add(n);
                nonRootJoinNodeClosure.addAll(n.getDependencies());
            }
        }
        return nonRootJoinNodeClosure;
    }

    @Override
    public void visit(PathExpression expression) {
        joinNodes.add((JoinNode) expression.getBaseNode());
    }
}