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package oracle.toplink.essentials.internal.parsing;

import java.util.*;

/**
 * INTERNAL
 * <p><b>Purpose</b>: Represent a FROM
 * <p><b>Responsibilities</b>:<ul>
 * <li> Determines the context for the Parse Tree
 * <li> Determine the reference class for a query
 * <li> Handle any FROM ... IN clauses
 * </ul>
 *    @author Jon Driscoll
 *    @since TopLink 5.0
 */
public class FromNode extends MajorNode {

    private List declarations;

    public String getFirstVariable() {
        String variable = null;
        if ((declarations != null) && (declarations.size() > 0)) {
            variable = ((IdentificationVariableDeclNode)declarations.get(0)).getCanonicalVariableName();
        }
        return variable;
    }

    public List getDeclarations() {
        return declarations;
    }
    
    public void setDeclarations(List decls) {
        declarations = decls;
    }
    
    /** 
     * INTERNAL 
     * Check the declaration nodes for a path expression starting with a
     * unqualified field access and if so, replace it by a qualified field
     * access. 
     */
    public Node qualifyAttributeAccess(ParseTreeContext context) {
        for (int i = 0; i < declarations.size(); i++) {
            Node decl = (Node)declarations.get(i);
            declarations.set(i, decl.qualifyAttributeAccess(context));
        }
        return this;
    }
    
    /**
     * INTERNAL
     * Validate the current node.
     */
    public void validate(ParseTreeContext context) {
        for (Iterator i = declarations.iterator(); i.hasNext();) {
            Node decl = (Node)i.next();
            decl.validate(context);
        }
    }
}