jakarta.el.ValueExpression Maven / Gradle / Ivy
/*
* 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 jakarta.el;
public abstract class ValueExpression extends Expression {
private static final long serialVersionUID = 8577809572381654673L;
/**
* @param The expected type for the result of evaluating this value expression
* @param context The EL context for this evaluation
*
* @return The result of evaluating this value expression
*
* @throws NullPointerException If the supplied context is null
* @throws PropertyNotFoundException If a property/variable resolution failed because no match was found or a match
* was found but was not readable
* @throws ELException Wraps any exception throw whilst resolving a property or variable
*/
public abstract T getValue(ELContext context);
/**
* @param context The EL context for this evaluation
* @param value The value to set the property to which this value expression refers
*
* @throws NullPointerException If the supplied context is null
* @throws PropertyNotFoundException If a property/variable resolution failed because no match was found
* @throws PropertyNotWritableException If a property/variable resolution failed because a match was found but was
* not writable
* @throws ELException Wraps any exception throw whilst resolving a property or variable
*/
public abstract void setValue(ELContext context, Object value);
/**
* @param context The EL context for this evaluation
*
* @return true if this expression is read only otherwise false
*
* @throws NullPointerException If the supplied context is null
* @throws PropertyNotFoundException If a property/variable resolution failed because no match was found or a match
* was found but was not readable
* @throws ELException Wraps any exception throw whilst resolving a property or variable
*/
public abstract boolean isReadOnly(ELContext context);
/**
* @param context The EL context for this evaluation
*
* @return The type of the result of this value expression
*
* @throws NullPointerException If the supplied context is null
* @throws PropertyNotFoundException If a property/variable resolution failed because no match was found or a match
* was found but was not readable
* @throws ELException Wraps any exception throw whilst resolving a property or variable
*/
public abstract Class getType(ELContext context);
public abstract Class getExpectedType();
/**
* @param context The EL context for this evaluation
*
* @return This default implementation always returns null
*
* @since EL 2.2
*/
public ValueReference getValueReference(ELContext context) {
// Expected to be over-ridden by implementation
context.notifyBeforeEvaluation(getExpressionString());
context.notifyAfterEvaluation(getExpressionString());
return null;
}
}