com.isotrol.impe3.core.component.ActionExtractors.java Source code

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Here is the source code for com.isotrol.impe3.core.component.ActionExtractors.java

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/**
 * This file is part of Port@l
 * Port@l 3.0 - Portal Engine and Management System
 * Copyright (C) 2010  Isotrol, SA.  http://www.isotrol.com
 *
 * Port@l is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Port@l is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Port@l.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.isotrol.impe3.core.component;

import java.lang.reflect.Method;
import java.util.List;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.isotrol.impe3.api.component.Action;
import com.isotrol.impe3.api.component.Component;
import com.isotrol.impe3.api.component.ExtractAction;

/**
 * Collection of action extractors.
 * @author Andres Rodriguez
 * @param <T> Target component type.
 */
public final class ActionExtractors<T extends Component> extends Extractors<T> {
    private final ImmutableSet<ActionExtractor> extractors;

    static <T extends Component> ActionExtractors<T> of(Class<T> type, Iterable<Method> methods) {
        return new ActionExtractors<T>(type, filter(methods, ExtractAction.class));
    }

    private ActionExtractors(final Class<T> type, Iterable<Method> methods) {
        super(type);
        final ImmutableSet.Builder<ActionExtractor> builder = ImmutableSet.builder();
        for (Method m : methods) {
            final ActionExtractor e = new ActionExtractor(m);
            builder.add(e);
        }
        this.extractors = builder.build();
    }

    @Override
    public boolean isEmpty() {
        return extractors.isEmpty();
    }

    /**
     * Performs an extraction.
     * @param target Target object.
     * @return Actions to register.
     */
    public final List<Action> extract(Object target) {
        if (isEmpty()) {
            return ImmutableList.of();
        }
        final List<Action> actions = Lists.newArrayListWithCapacity(extractors.size());
        for (ActionExtractor e : extractors) {
            final Action action = e.extract(target);
            if (action != null) {
                actions.add(action);
            }
        }
        return actions;
    }

    /**
     * A direct extractor.
     * @author Andres Rodriguez
     */
    private class ActionExtractor extends Extractor {
        ActionExtractor(final Method method) {
            super(method);
            if (getReturnType() != Action.class) {
                throw new IllegalExtractionMethodException(getType(), method);
            }
        }

        /**
         * Extracts the value.
         * @param target Target object.
         * @return Extracted value.
         */
        public final Action extract(Object target) {
            return (Action) invoke(target);
        }
    }
}