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 */
017
018package org.apache.commons.jexl3.internal.introspection;
019import java.lang.reflect.InvocationTargetException;
020import org.apache.commons.jexl3.JexlException;
021/**
022 * Specialized executor to get a boolean property from an object.
023 * @since 2.0
024 */
025public final class BooleanGetExecutor extends AbstractExecutor.Get {
026    /** The property. */
027    private final String property;
028
029    /**
030     * Discovers a BooleanGetExecutor.
031     * <p>The method to be found should be named "is{P,p}property and return a boolean.</p>
032     *
033     * @param is the introspector
034     * @param clazz the class to find the get method from
035     * @param property the property name
036     * @return the executor if found, null otherwise
037     */
038    public static BooleanGetExecutor discover(final Introspector is, final Class<?> clazz, final String property) {
039        if (property != null && !property.isEmpty()) {
040            final java.lang.reflect.Method m = PropertyGetExecutor.discoverGet(is, "is", clazz, property);
041            if (m != null && (m.getReturnType() == Boolean.TYPE || m.getReturnType() == Boolean.class)) {
042                return new BooleanGetExecutor(clazz, m, property);
043            }
044        }
045        return null;
046    }
047
048    /**
049     * Creates an instance by attempting discovery of the get method.
050     * @param clazz the class to introspect
051     * @param method the method held by this executor
052     * @param key the property to get
053     */
054    private BooleanGetExecutor(final Class<?> clazz, final java.lang.reflect.Method method, final String key) {
055        super(clazz, method);
056        property = key;
057    }
058
059    @Override
060    public Object getTargetProperty() {
061        return property;
062    }
063
064    @Override
065    public Object invoke(final Object obj) throws IllegalAccessException, InvocationTargetException {
066        return method == null ? null : method.invoke(obj, (Object[]) null);
067    }
068
069    @Override
070    public Object tryInvoke(final Object obj, final Object key) {
071        if (obj != null && method !=  null
072            // ensure method name matches the property name
073            && property.equals(key)
074            && objectClass.equals(obj.getClass())) {
075            try {
076                return method.invoke(obj, (Object[]) null);
077            } catch (final IllegalAccessException xill) {
078                return TRY_FAILED;// fail
079            } catch (final InvocationTargetException xinvoke) {
080                throw JexlException.tryFailed(xinvoke); // throw
081            }
082        }
083        return TRY_FAILED;
084    }
085}