org.apache.openjpa.kernel.exps.Value Maven / Gradle / Ivy
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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
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.kernel.exps;
import java.io.Serializable;
import org.apache.openjpa.meta.ClassMetaData;
/**
* Interface for any non-operator in a query filter, including
* constants, variables, and object fields.
*
* @author Abe White
*/
public interface Value
extends Serializable {
/**
* Return the expected type for this value, or Object if
* the type is unknown.
*/
Class getType();
/**
* Set the implicit type of the value, based on how it is used in the
* filter. This method is only called on values who return
* Object from {@link #getType}.
*/
void setImplicitType(Class type);
/**
* Return true if this value is a variable.
*/
boolean isVariable();
/**
* Return true if this value is an aggregate.
*/
boolean isAggregate();
/**
* Return true if this value is an XML Path.
*/
boolean isXPath();
/**
* Return any associated persistent type.
*/
ClassMetaData getMetaData();
/**
* Associate a persistent type with this value.
*/
void setMetaData(ClassMetaData meta);
/**
* Accept a visit from a tree visitor.
*/
void acceptVisit(ExpressionVisitor visitor);
/**
* Return select item alias
*/
String getAlias();
/**
* Set select item alias
*/
void setAlias(String alias);
/**
* Return 'this' concrete class if alias is set, otherwise null
*/
Value getSelectAs();
Path getPath();
String getName();
}