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package com.hazelcast.shaded.org.apache.calcite.schema;

import com.hazelcast.shaded.org.apache.calcite.linq4j.Queryable;
import com.hazelcast.shaded.org.apache.calcite.rel.type.RelDataType;

import java.util.List;

/**
 * A named expression in a schema.
 *
 * 

Examples of members

* *

Several kinds of members crop up in real life. They all implement the * {@code Member} interface, but tend to be treated differently by the * back-end system if not by Calcite. * *

A member that has zero arguments and a type that is a collection of * records is referred to as a relation. In schemas backed by a * relational database, tables and views will appear as relations. * *

A member that has one or more arguments and a type that is a collection * of records is referred to as a parameterized relation. Some relational * databases support these; for example, Oracle calls them "table * functions". * *

Members may be also more typical of programming-language functions: * they take zero or more arguments, and return a result of arbitrary type. * *

From the above definitions, you can see that a member is a special * kind of function. This makes sense, because even though it has no * arguments, it is "evaluated" each time it is used in a query. */ public interface Member { /** * The name of this function. */ String getName(); /** * Returns the parameters of this member. * * @return Parameters; never null */ List getParameters(); /** * Returns the type of this function's result. * * @return Type of result; never null */ RelDataType getType(); /** * Evaluates this member to yield a result. The result is a * {@link com.hazelcast.shaded.org.apache.calcite.linq4j.Queryable}. * * @param schemaInstance Object that is an instance of the containing * {@link Schema} * @param arguments List of arguments to the call; must match * {@link #getParameters() parameters} in number and type * * @return An instance of this schema object, as a Queryable */ Queryable evaluate( Object schemaInstance, List arguments); }