BinaryNode.java

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//   http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.doris.nereids.trees;

/**
 * interface for all tree node that have two children.
 */
public interface BinaryNode<
            NODE_TYPE extends TreeNode<NODE_TYPE>,
            LEFT_CHILD_TYPE extends TreeNode,
            RIGHT_CHILD_TYPE extends TreeNode>
        extends TreeNode<NODE_TYPE> {

    default LEFT_CHILD_TYPE left() {
        return (LEFT_CHILD_TYPE) child(0);
    }

    default RIGHT_CHILD_TYPE right() {
        return (RIGHT_CHILD_TYPE) child(1);
    }

    @Override
    default int arity() {
        return 2;
    }
}