com.abiquo.commons.plugin.internal.ContextPropertiesInvocationHandler Maven / Gradle / Ivy

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/**
 * The Abiquo Platform
 * Cloud management application for hybrid clouds
 * Copyright (C) 2008 - Abiquo Holdings S.L.
 *
 * This application is free software; you can redistribute it and/or
 * modify it under the terms of the GNU LESSER GENERAL PUBLIC
 * LICENSE as published by the Free Software Foundation under
 * version 3 of the License
 *
 * This software 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
 * LESSER GENERAL PUBLIC LICENSE v.3 for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
package com.abiquo.commons.plugin.internal;

import static com.google.common.collect.Sets.newHashSet;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

import com.abiquo.commons.plugin.IConnection;
import com.abiquo.commons.plugin.WithContextProperties;
import com.abiquo.commons.plugin.annotation.ContextProperties;
import com.abiquo.commons.plugin.exception.ComputeException;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMap.Builder;

public class ContextPropertiesInvocationHandler implements InvocationHandler
{
    private final Object target;

    private final Map> PROPERTIES_BY_METHODNAME;

    public ContextPropertiesInvocationHandler(final Object target)
    {
        this.target = Objects.requireNonNull(target);
        this.PROPERTIES_BY_METHODNAME = contextPropertiesByMethodName(target);
    }

    @Override
    public Object invoke(final Object proxy, final Method method, final Object[] args)
        throws UnsupportedOperationException, ComputeException
    {
        return new HashSet<>(PROPERTIES_BY_METHODNAME.getOrDefault(method.getName(),
            Collections.emptySet()));
    }

    private Map> contextPropertiesByMethodName(final Object plugin)
    {
        Builder> builder = ImmutableMap.> builder();
        if (target != null)
        {
            for (Method m : plugin.getClass().getMethods())
            {
                if (!m.isSynthetic() && !m.isBridge())
                {
                    ContextProperties props = m.getAnnotation(ContextProperties.class);
                    if (props != null)
                    {
                        // IConnection should implement WithContextProperties
                        if (!Arrays.stream(m.getParameterTypes()).anyMatch(
                            c -> WithContextProperties.class.isAssignableFrom(c)
                                && IConnection.class.isAssignableFrom(c)))
                        {
                            throw new IllegalStateException("Cannot load "
                                + target.getClass().getSimpleName()
                                + " method "
                                + m.getName()
                                + " uses @ContextProperties but it doesn't receive a IConnection implementing WithContextProperties");
                        }

                        builder.put(m.getName(), newHashSet(props.value()));
                    }
                }
            }
        }
        return builder.build();
    }
}