/*
 * 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.
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package jakarta.el;

public abstract class ValueExpression extends Expression {

    private static final long serialVersionUID = 8577809572381654673L;

    
Params:
  • context – The EL context for this evaluation
Throws:
Returns: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 <code>null</code> * @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 Object getValue(ELContext context);
Params:
  • context – The EL context for this evaluation
  • value – The value to set the property to which this value expression refers
Throws:
/** * @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 <code>null</code> * @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);
Params:
  • context – The EL context for this evaluation
Throws:
Returns:true if this expression is read only otherwise false
/** * @param context The EL context for this evaluation * * @return <code>true</code> if this expression is read only otherwise * <code>false</code> * * @throws NullPointerException * If the supplied context is <code>null</code> * @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);
Params:
  • context – The EL context for this evaluation
Throws:
Returns:The type of the result of this value expression
/** * @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 <code>null</code> * @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();
Params:
  • context – The EL context for this evaluation
Returns:This default implementation always returns null
Since:EL 2.2
/** * @param context The EL context for this evaluation * * @return This default implementation always returns <code>null</code> * * @since EL 2.2 */
public ValueReference getValueReference(ELContext context) { // Expected to be over-ridden by implementation context.notifyBeforeEvaluation(getExpressionString()); context.notifyAfterEvaluation(getExpressionString()); return null; } }