ExplicitCollateNode.java

/**
 * Copyright © 2012 Akiban Technologies, Inc.  All rights
 * reserved.
 *
 * This program and the accompanying materials are made available
 * under the terms of the Eclipse Public License v1.0 which
 * accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * This program may also be available under different license terms.
 * For more information, see www.akiban.com or contact
 * licensing@akiban.com.
 *
 * Contributors:
 * Akiban Technologies, Inc.
 */

package com.akiban.sql.parser;

import com.akiban.sql.StandardException;

/**
 * This node represents a COLLATE clause attached to an expression.
 *
 */
public class ExplicitCollateNode extends ValueNode
{
    private ValueNode operand;
    private String collation;

    /**
     * Initializer for a ExplicitCollateNode
     *
     * @param operand   The operand
     * @param collation The explicit collation
     */
    public void init(Object operand, Object collation) throws StandardException {
        this.operand = (ValueNode)operand;
        this.collation = (String)collation;
    }

    /**
     * Fill this node with a deep copy of the given node.
     */
    public void copyFrom(QueryTreeNode node) throws StandardException {
        super.copyFrom(node);

        ExplicitCollateNode other = (ExplicitCollateNode)node;
        this.operand = (ValueNode)getNodeFactory().copyNode(other.operand,
                                                            getParserContext());
        this.collation = other.collation;
    }

    /**
     * Convert this object to a String.  See comments in QueryTreeNode.java
     * for how this should be done for tree printing.
     *
     * @return This object as a String
     */

    public String toString() {
        return "collation: " + collation + "\n" +
            super.toString();
    }

    /**
     * Prints the sub-nodes of this object.  See QueryTreeNode.java for
     * how tree printing is supposed to work.
     *
     * @param depth The depth of this node in the tree
     */

    public void printSubNodes(int depth) {
        super.printSubNodes(depth);

        if (operand != null) {
            printLabel(depth, "operand: ");
            operand.treePrint(depth + 1);
        }
    }

    /**
     * Get the operand of this unary operator.
     *
     * @return The operand of this unary operator.
     */
    public ValueNode getOperand() {
        return operand;
    }

    public String getCollation() {
        return collation;
    }

    /**
     * Accept the visitor for all visitable children of this node.
     * 
     * @param v the visitor
     *
     * @exception StandardException on error
     */
    void acceptChildren(Visitor v) throws StandardException {
        super.acceptChildren(v);

        if (operand != null) {
            operand = (ValueNode)operand.accept(v);
        }
    }

    /**
     * @throws StandardException 
     * {@inheritDoc}
     */
    protected boolean isEquivalent(ValueNode o) throws StandardException {
        if (isSameNodeType(o)) {
            // the first condition in the || covers the case when 
            // both operands are null.
            ExplicitCollateNode other = (ExplicitCollateNode)o;
            return (collation.equals(other.collation) && 
                    ((operand == other.operand)|| 
                     ((operand != null) && operand.isEquivalent(other.operand))));
        }
        return false;
    }

}