/*
 * Copyright 2002-2018 the original author or authors.
 *
 * 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
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 * Unless required by applicable law or agreed to in writing, software
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package org.springframework.expression;

import java.util.List;

import org.springframework.lang.Nullable;

Expressions are executed in an evaluation context. It is in this context that references are resolved when encountered during expression evaluation.

There is a default implementation of this EvaluationContext interface: StandardEvaluationContext which can be extended, rather than having to implement everything manually.

Author:Andy Clement, Juergen Hoeller
Since:3.0
/** * Expressions are executed in an evaluation context. It is in this context that * references are resolved when encountered during expression evaluation. * * <p>There is a default implementation of this EvaluationContext interface: * {@link org.springframework.expression.spel.support.StandardEvaluationContext} * which can be extended, rather than having to implement everything manually. * * @author Andy Clement * @author Juergen Hoeller * @since 3.0 */
public interface EvaluationContext {
Return the default root context object against which unqualified properties/methods/etc should be resolved. This can be overridden when evaluating an expression.
/** * Return the default root context object against which unqualified * properties/methods/etc should be resolved. This can be overridden * when evaluating an expression. */
TypedValue getRootObject();
Return a list of accessors that will be asked in turn to read/write a property.
/** * Return a list of accessors that will be asked in turn to read/write a property. */
List<PropertyAccessor> getPropertyAccessors();
Return a list of resolvers that will be asked in turn to locate a constructor.
/** * Return a list of resolvers that will be asked in turn to locate a constructor. */
List<ConstructorResolver> getConstructorResolvers();
Return a list of resolvers that will be asked in turn to locate a method.
/** * Return a list of resolvers that will be asked in turn to locate a method. */
List<MethodResolver> getMethodResolvers();
Return a bean resolver that can look up beans by name.
/** * Return a bean resolver that can look up beans by name. */
@Nullable BeanResolver getBeanResolver();
Return a type locator that can be used to find types, either by short or fully qualified name.
/** * Return a type locator that can be used to find types, either by short or * fully qualified name. */
TypeLocator getTypeLocator();
Return a type converter that can convert (or coerce) a value from one type to another.
/** * Return a type converter that can convert (or coerce) a value from one type to another. */
TypeConverter getTypeConverter();
Return a type comparator for comparing pairs of objects for equality.
/** * Return a type comparator for comparing pairs of objects for equality. */
TypeComparator getTypeComparator();
Return an operator overloader that may support mathematical operations between more than the standard set of types.
/** * Return an operator overloader that may support mathematical operations * between more than the standard set of types. */
OperatorOverloader getOperatorOverloader();
Set a named variable within this evaluation context to a specified value.
Params:
  • name – variable to set
  • value – value to be placed in the variable
/** * Set a named variable within this evaluation context to a specified value. * @param name variable to set * @param value value to be placed in the variable */
void setVariable(String name, @Nullable Object value);
Look up a named variable within this evaluation context.
Params:
  • name – variable to lookup
Returns:the value of the variable, or null if not found
/** * Look up a named variable within this evaluation context. * @param name variable to lookup * @return the value of the variable, or {@code null} if not found */
@Nullable Object lookupVariable(String name); }