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.jexl2.internal;
019import java.lang.reflect.InvocationTargetException;
020/**
021 * Specialized executor to get a boolean property from an object.
022 * @since 2.0
023 */
024public final class BooleanGetExecutor extends AbstractExecutor.Get {
025    /** The property. */
026    private final String property;
027    /**
028     * Creates an instance by attempting discovery of the get method.
029     * @param is the introspector
030     * @param clazz the class to introspect
031     * @param key the property to get
032     */
033    public BooleanGetExecutor(Introspector is, Class<?> clazz, String key) {
034        super(clazz, discover(is, clazz, key));
035        property = key;
036    }
037
038    /** {@inheritDoc} */
039    @Override
040    public Object getTargetProperty() {
041        return property;
042    }
043
044    /** {@inheritDoc} */
045    @Override
046    public Object execute(Object obj)
047        throws IllegalAccessException, InvocationTargetException {
048        return method == null ? null : method.invoke(obj, (Object[]) null);
049    }
050    
051    /** {@inheritDoc} */
052    @Override
053    public Object tryExecute(Object obj, Object key) {
054        if (obj != null && method !=  null
055            // ensure method name matches the property name
056            && property.equals(key)
057            && objectClass.equals(obj.getClass())) {
058            try {
059                return method.invoke(obj, (Object[]) null);
060            } catch (InvocationTargetException xinvoke) {
061                return TRY_FAILED; // fail
062            } catch (IllegalAccessException xill) {
063                return TRY_FAILED;// fail
064            }
065        }
066        return TRY_FAILED;
067    }
068
069    /**
070     * Discovers the method for a {@link BooleanGet}.
071     * <p>The method to be found should be named "is{P,p}property and return a boolean.</p>
072     *@param is the introspector
073     *@param clazz the class to find the get method from
074     *@param property the the property name
075     *@return the method if found, null otherwise
076     */
077    static java.lang.reflect.Method discover(Introspector is, final Class<?> clazz, String property) {
078        java.lang.reflect.Method m = PropertyGetExecutor.discoverGet(is, "is", clazz, property);
079        return (m != null && m.getReturnType() == Boolean.TYPE) ? m : null;
080    }
081
082}