/*
 * 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;

/**
 * Represents a compiled EL method expression. A MethodExpression is the result of compiling an EL expression
 * that resolves to a method, and can be invoked at a later time with a given set of parameters.
 */
public abstract class MethodExpression extends Expression {

    private static final long serialVersionUID = 8163925562047324656L;

    /**
     * Constructs a MethodExpression.
     */
    public MethodExpression() {
    }

    /**
     * Returns information about the method that this expression resolves to.
     *
     * @param context The EL context for this evaluation
     *
     * @return Information about the method that this expression resolves to
     *
     * @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 MethodNotFoundException   If no matching method can be found
     * @throws ELException               Wraps any exception throw whilst resolving the property
     */
    public abstract MethodInfo getMethodInfo(ELContext context);

    /**
     * Invokes the method that this expression resolves to with the given parameters.
     *
     * @param context The EL context for this evaluation
     * @param params  The parameters with which to invoke this method expression
     *
     * @return The result of invoking this method 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 MethodNotFoundException   If no matching method can be found
     * @throws ELException               Wraps any exception throw whilst resolving the property or coercion of the
     *                                       result to the expected return type fails
     */
    public abstract Object invoke(ELContext context, Object[] params);

    /**
     * Returns whether the parameters for the method invocation are provided by the expression or by the container.
     *
     * @return This default implementation always returns <code>false</code>
     *
     * @since EL 3.0
     */
    public boolean isParametersProvided() {
        // Expected to be over-ridden by implementation
        return false;
    }

    /**
     * Obtain the {@link MethodReference} for the method to which this method expression resolves.
     *
     * @param context The EL context for this evaluation
     *
     * @return This default implementation always returns <code>null</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 MethodNotFoundException   If no matching method can be found
     * @throws ELException               Wraps any exception throw whilst resolving the property
     *
     * @since EL 5.0
     */
    public MethodReference getMethodReference(ELContext context) {
        // Expected to be over-ridden by implementation
        context.notifyBeforeEvaluation(getExpressionString());
        context.notifyAfterEvaluation(getExpressionString());
        return null;
    }
}
