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An aggregation of 1.4, 1.5 modules into an ROP client jar.
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 *   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
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 *    http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cayenne.exp.parser;

import java.io.PrintWriter;

import org.apache.cayenne.ObjectId;
import org.apache.cayenne.Persistent;
import org.apache.cayenne.exp.Expression;

/**
 * A scalar value wrapper expression.
 * 
 * @since 1.1
 */
public class ASTScalar extends SimpleNode {

    protected Object value;

    /**
     * Constructor used by expression parser. Do not invoke directly.
     */
    ASTScalar(int id) {
        super(id);
    }

    public ASTScalar() {
        super(ExpressionParserTreeConstants.JJTSCALAR);
    }

    public ASTScalar(Object value) {
        super(ExpressionParserTreeConstants.JJTSCALAR);
        setValue(value);
    }

    @Override
    protected Object evaluateNode(Object o) throws Exception {
        return value;
    }

    /**
     * Creates a copy of this expression node, without copying children.
     */
    @Override
    public Expression shallowCopy() {
        ASTScalar copy = new ASTScalar(id);
        copy.value = value;
        return copy;
    }

    @Override
    public void encodeAsString(PrintWriter pw) {
        SimpleNode.encodeScalarAsString(pw, value, '\"');
    }

    /**
     * @since 3.0
     */
    @Override
    public void encodeAsEJBQL(PrintWriter pw, String rootId) {

        // TODO: see CAY-1111
        // Persistent processing is a hack for a rather special case of a single column PK
        // object.. full implementation pending...
        Object scalar = value;
        if (scalar instanceof Persistent) {

            Persistent persistent = (Persistent) scalar;
            ObjectId id = persistent.getObjectId();
            if (!id.isTemporary() && id.getIdSnapshot().size() == 1) {
                scalar = id.getIdSnapshot().values().iterator().next();
            }
        }

        SimpleNode.encodeScalarAsString(pw, scalar, '\'');
    }

    public void setValue(Object value) {
        this.value = value;
    }

    public Object getValue() {
        return value;
    }

    @Override
    protected String getExpressionOperator(int index) {
        throw new UnsupportedOperationException("No operator for '"
                + ExpressionParserTreeConstants.jjtNodeName[id]
                + "'");
    }
}