    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.jexl3;
    018
    019import org.apache.commons.jexl3.introspection.JexlPropertyGet;
    020import org.apache.commons.jexl3.introspection.JexlPropertySet;
    021
    022/**
    023 * Wraps an Object as a JEXL context and NamespaceResolver.
    024 *
    025 * @param <T> the wrapped object type to use
    026 * @since 3.0
    027 */
    028public class ObjectContext<T> implements JexlContext, JexlContext.NamespaceResolver {
    029
    030    /** The property solving jexl engine. */
    031    private final JexlEngine jexl;
    032
    033    /** The object serving as context provider. */
    034    private final T object;
    035
    036    /**
    037     * @return the Jexl engine
    038     */
    039    protected JexlEngine getJexl() {
    040        return jexl;
    041    }
    042
    043    /**
    044     * @return the object exposed by this context
    045     */
    046    protected T getObject() {
    047        return object;
    048    }
    049
    050    /**
    051     * Creates a new ObjectContext.
    052     *
    053     * @param engine  the jexl engine to use to solve properties
    054     * @param wrapped the object to wrap in this context
    055     */
    056    public ObjectContext(final JexlEngine engine, final T wrapped) {
    057        this.jexl = engine;
    058        this.object = wrapped;
    059    }
    060
    061    @Override
    062    public Object get(final String name) {
    063        final JexlPropertyGet jget = jexl.getUberspect().getPropertyGet(object, name);
    064        if (jget != null) {
    065            try {
    066                return jget.invoke(object);
    067            } catch (final Exception xany) {
    068                if (jexl.isStrict()) {
    069                    throw new JexlException.Property(null, name, true, xany);
    070                }
    071            }
    072        }
    073        return null;
    074    }
    075
    076    @Override
    077    public void set(final String name, final Object value) {
    078        final JexlPropertySet jset = jexl.getUberspect().getPropertySet(object, name, value);
    079        if (jset != null) {
    080            try {
    081                jset.invoke(object, value);
    082            } catch (final Exception xany) {
    083                // ignore
    084                if (jexl.isStrict()) {
    085                    throw new JexlException.Property(null, name, true, xany);
    086                }
    087            }
    088        }
    089    }
    090
    091    @Override
    092    public boolean has(final String name) {
    093        final JexlPropertyGet jget = jexl.getUberspect().getPropertyGet(object, name);
    094        try {
    095            return jget != null && jget.invoke(object) != null;
    096        } catch (final Exception xany) {
    097            return false;
    098        }
    099    }
    100
    101    @Override
    102    public Object resolveNamespace(final String name) {
    103        if (name == null || name.isEmpty()) {
    104            return object;
    105        }
    106        return null;
    107    }
    108}