/*
 * Copyright 2019-2021 The Polypheny Project
 *
 * Licensed 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.
 *
 * This file incorporates code covered by the following terms:
 *
 * 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.polypheny.db.algebra;


/**
 * Exception that indicates that a relational expression would be invalid with given parameters.
 *
 * This exception is thrown by the constructor of a subclass of {@link AlgNode} when given parameters it cannot accept. For example, {@code EnumerableJoinRel} can only implement equi-joins,
 * so its constructor throws {@code InvalidRelException} when given the condition {@code input0.x - input1.y = 2}.
 *
 * Because the exception is checked (i.e. extends {@link Exception} but not {@link RuntimeException}), constructors that throw this exception will declare this exception in their {@code throws} clause,
 * and rules that create those relational expressions will need to handle it. Usually a rule will not take the exception personally, and will fail to match. The burden of checking is removed from the rule,
 * which means less code for the author of the rule to maintain.
 *
 * The caller that receives an {@code InvalidRelException} (typically a rule attempting to create a relational expression) should log it at the DEBUG level.
 */
public class InvalidAlgException extends Exception {

    /**
     * Creates an InvalidRelException.
     */
    public InvalidAlgException( String message ) {
        super( message );
    }


    /**
     * Creates an InvalidRelException with a cause.
     */
    public InvalidAlgException( String message, Throwable cause ) {
        super( message, cause );
    }

}
