org.mvel2.optimizers.impl.refl.nodes.FieldAccessor Maven / Gradle / Ivy

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/**
 * MVEL (The MVFLEX Expression Language)
 *
 * Copyright (C) 2007 Christopher Brock, MVFLEX/Valhalla Project and the Codehaus
 *
 * 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
 *
 * 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 org.mvel2.optimizers.impl.refl.nodes;

import static org.mvel2.DataConversion.convert;

import java.lang.reflect.Field;

import org.mvel2.compiler.AccessorNode;
import org.mvel2.integration.VariableResolverFactory;
import org.mvel2.util.PropertyTools;

public class FieldAccessor implements AccessorNode {

    private AccessorNode nextNode;
    private Field field;
    private boolean coercionRequired = false;
    private boolean primitive;

    public FieldAccessor() {
    }

    public FieldAccessor(Field field) {
        primitive = (this.field = field).getType().isPrimitive();
    }

    public Object getValue(Object ctx, Object elCtx, VariableResolverFactory vars) {
        try {
            if (nextNode != null) {
                return nextNode.getValue(field.get(ctx), elCtx, vars);
            } else {
                return field.get(ctx);
            }
        } catch (Exception e) {
            throw new RuntimeException("unable to access field: " + field.getName(), e);
        }
    }

    public Object setValue(Object ctx, Object elCtx, VariableResolverFactory variableFactory, Object value) {
        if (nextNode != null) {
            try {
                return nextNode.setValue(field.get(ctx), elCtx, variableFactory,
                        value == null && primitive ? PropertyTools.getPrimitiveInitialValue(field.getType()) : value);
            } catch (Exception e) {
                throw new RuntimeException("unable to access field", e);
            }
        }

        // this local field is required to make sure exception block works with the same coercionRequired value
        // and it is not changed by another thread while setter is invoked 
        boolean attemptedCoercion = coercionRequired;
        try {

            if (coercionRequired) {
                field.set(ctx, value = convert(ctx, field.getClass()));
                return value;
            } else {
                field.set(ctx, value);
                return value;
            }
        } catch (IllegalArgumentException e) {
            if (!attemptedCoercion) {
                coercionRequired = true;
                return setValue(ctx, elCtx, variableFactory, value);
            }
            throw new RuntimeException("unable to bind property", e);
        } catch (Exception e) {
            throw new RuntimeException("unable to access field", e);
        }
    }

    public Field getField() {
        return field;
    }

    public void setField(Field field) {
        this.field = field;
    }

    public AccessorNode getNextNode() {
        return nextNode;
    }

    public AccessorNode setNextNode(AccessorNode nextNode) {
        return this.nextNode = nextNode;
    }

    public Class getKnownEgressType() {
        return field.getClass();
    }
}