org.eclipse.persistence.internal.jpa.parsing.CoalesceNode Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation
EclipseLink build based upon Git transaction f2b9fc5
There is a newer version: 5.0.0-B03
/*
 * Copyright (c) 1998, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     tware - initial implementation as part of JPA 2.0 RI
package org.eclipse.persistence.internal.jpa.parsing;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.persistence.expressions.Expression;
import org.eclipse.persistence.queries.ObjectLevelReadQuery;
import org.eclipse.persistence.queries.ReportQuery;

/**
 * INTERNAL
 * Purpose: Represent an COALESCE in EJBQL
 * 
Responsibilities:

 *  Generate the correct expression for an COALESCE in EJBQL
 * 
 *    @author tware
 *    @since EclipseLink 1.2
 */
public class CoalesceNode extends Node implements AliasableNode {

    private List clauses = null;

    public CoalesceNode(){
        super();
    }

    /**
     * INTERNAL
     * Apply this node to the passed query
     */
    public void applyToQuery(ObjectLevelReadQuery theQuery, GenerationContext generationContext) {
        if (theQuery instanceof ReportQuery) {
            ReportQuery reportQuery = (ReportQuery)theQuery;
            Expression expression = generateExpression(generationContext);
            reportQuery.addItem("Coalesce", expression);
        }
    }

    /**
     * INTERNAL
     * Generate the a new EclipseLink Coalesce expression for this node.
     */
    public Expression generateExpression(GenerationContext context) {
        List expressions = new ArrayList();
        Iterator i = clauses.iterator();
        while (i.hasNext()){
            expressions.add(((Node)i.next()).generateExpression(context));
        }

        Expression whereClause = context.getBaseExpression().coalesce(expressions);
        return whereClause;
    }

    public void validate(ParseTreeContext context) {
        TypeHelper typeHelper = context.getTypeHelper();
        Iterator i = clauses.iterator();
        Object type = null;
        while (i.hasNext()){
            Node node = ((Node)i.next());
            node.validate(context);
            if (type == null){
                type = node.getType();
            } else if (!type.equals(node.getType())){
                type = typeHelper.getObjectType();
            }
        }
        setType(((Node)clauses.get(0)).getType());
    }

    public List getClauses() {
        return clauses;
    }

    public void setClauses(List clauses) {
        this.clauses = clauses;
    }

    public boolean isAliasableNode(){
        return true;
    }

    public String toString(int indent) {
        StringBuilder buffer = new StringBuilder();
        buffer.append("COALESCE");
        buffer.append("(");

        Iterator i = clauses.iterator();
        while (i.hasNext()) {
            Node n = (Node) i.next();
            buffer.append(n.toString(indent));
            buffer.append("\r\n");
        }
        toStringIndent(indent, buffer);
        buffer.append(")");
        return buffer.toString();
    }
}