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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
 *  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 org.apache.cayenne.exp.parser;

import java.io.IOException;
import java.util.List;

import org.apache.cayenne.exp.Expression;
import org.apache.cayenne.exp.ExpressionException;
import org.apache.cayenne.exp.ExpressionParameter;

/**
 * A named expression parameter.
 * 
 * @since 1.1
 */
public class ASTNamedParameter extends ASTScalar {

	private static final long serialVersionUID = -3965588358977704022L;

	ASTNamedParameter(int id) {
		super(id);
	}

	public ASTNamedParameter() {
		super(ExpressionParserTreeConstants.JJTNAMEDPARAMETER);
	}

	public ASTNamedParameter(Object value) {
		super(ExpressionParserTreeConstants.JJTNAMEDPARAMETER);
		setValue(value);
	}

	@Override
	protected Object evaluateNode(Object o) throws Exception {
		throw new ExpressionException("Uninitialized parameter: " + value + ", call 'expWithParameters' first.");
	}

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

	@Override
	public void setValue(Object value) {
		if (value == null) {
			throw new ExpressionException("Null Parameter value");
		}

		String name = value.toString().trim();
		if (name.length() == 0) {
			throw new ExpressionException("Empty Parameter value");
		}

		super.setValue(new ExpressionParameter(name));
	}

	/**
	 * @since 4.0
	 */
	@Override
	public void appendAsEJBQL(List<Object> parameterAccumulator, Appendable out, String rootId) throws IOException {

		if (value != null) {
			String valueString = value.toString();
			if (valueString.length() > 1 && valueString.charAt(0) == '$') {
				out.append(':');
				out.append(valueString.substring(1));
				return;
			}
		}

		super.appendAsEJBQL(parameterAccumulator, out, rootId);
	}
}