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        return jexl.getUberspect().getPropertyGet(object, name) != null;
094    }
095
096    @Override
097    public Object resolveNamespace(final String name) {
098        if (name == null || name.isEmpty()) {
099            return object;
100        }
101        return null;
102    }
103}