/*******************************************************************************
* Copyright (c) 2006, 2015 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 v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation
*
******************************************************************************/
package org.eclipse.persistence.jpa.jpql.parser;
/**
* This {@link ExpressionVisitor} wraps another {@link ExpressionVisitor} and delegates all its
* calls to it (the delegate).
*
* @version 2.4
* @since 2.3
* @author Pascal Filion
*/
@SuppressWarnings("nls")
public abstract class ExpressionVisitorWrapper extends AnonymousExpressionVisitor {
/**
* The {@link ExpressionVisitor} that will have the calls delegated from this one.
*/
private final ExpressionVisitor delegate;
/**
* Creates a new <code>ExpressionVisitorWrapper</code>.
*/
@SuppressWarnings("unused")
private ExpressionVisitorWrapper() {
this(null);
}
/**
* Creates a new <code>ExpressionVisitorWrapper</code>.
*
* @param delegate The {@link ExpressionVisitor} that will have the calls delegated from this one
* @exception NullPointerException The delegate {@link ExpressionVisitor} cannot be null
*/
protected ExpressionVisitorWrapper(ExpressionVisitor delegate) {
super();
if (delegate == null) {
throw new NullPointerException("The delegate ExpressionVisitor cannot be null");
}
this.delegate = delegate;
}
/**
* Returns the delegate {@link ExpressionVisitor} that is receiving all the calls from this one.
*
* @return The delegate {@link ExpressionVisitor}
*/
protected ExpressionVisitor getDelegate() {
return delegate;
}
/**
* {@inheritDoc}
*/
@Override
protected void visit(Expression expression) {
expression.accept(delegate);
}
}