DMDirc-Client/src/com/dmdirc/ui/messages/EventPropertyManager.java

/*
 * Copyright (c) 2006-2015 DMDirc Developers
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.dmdirc.ui.messages;

import com.google.common.base.Strings;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.function.Function;

import javax.inject.Inject;
import javax.inject.Singleton;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static com.dmdirc.util.LogUtils.USER_ERROR;

/**
 * Provides properties and functions used by an {@link EventFormatter}.
 *
 * <p>Properties are dyanamically supplied based on get methods within the class. For example, if
 * channel objects have a 'getName()' method, then the name can be accessed as {{channel.name}}.
 *
 * <p>Functions are implemented as string transformations, and are defined in
 * {@link #EventPropertyManager()}.
 */
@Singleton
public class EventPropertyManager {

    private static final Logger LOG = LoggerFactory.getLogger(EventPropertyManager.class);
    private final Map<String, Function<String, String>> functions = new HashMap<>();

    @Inject
    public EventPropertyManager() {
        functions.put("uppercase", String::toUpperCase);
        functions.put("lowercase", String::toLowerCase);
        functions.put("trim", String::trim);
        functions.put("bracketed", s -> Strings.isNullOrEmpty(s) ? "" : " (" + s + ')');
    }

    public <S> Optional<Object> getProperty(final S object, final Class<? extends S> type,
            final String property) {
        final String methodName = "get" + property.substring(0, 1).toUpperCase()
                + property.substring(1);
        try {
            final Method method = type.getMethod(methodName);
            // TODO: This is needed for AutoValues, should probably get return types not real types
            method.setAccessible(true);
            final Object result = method.invoke(object);

            if (result instanceof Optional<?>) {
                return Optional.ofNullable(((Optional<?>) result).orElse(null));
            }

            return Optional.ofNullable(result);
        } catch (ReflectiveOperationException ex) {
            LOG.warn(USER_ERROR, "Unable to format event: could not retrieve property {}",
                    ex.getMessage(), ex);
        }
        return Optional.empty();
    }

    public String applyFunction(final String input, final String function) {
        if (functions.containsKey(function)) {
            return functions.get(function).apply(input);
        }
        LOG.info(USER_ERROR, "unable to format event: no such function {}", function);
        return input;
    }

}