org.apache.wicket.atmosphere.MethodEventSubscription.java Source code

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Here is the source code for org.apache.wicket.atmosphere.MethodEventSubscription.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.wicket.atmosphere;

import java.lang.reflect.Method;

import org.apache.wicket.Component;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.behavior.Behavior;

import com.google.common.base.Objects;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import java.lang.reflect.InvocationTargetException;
import org.apache.wicket.Page;
import org.apache.wicket.ajax.AjaxRequestTarget;

/**
 * The subscription of a method on a component to certain events. This is used by {@link EventBus}
 * to track the subscriptions.
 * 
 * @author papegaaij
 * @author floaz
 */
public class MethodEventSubscription implements EventSubscription {
    private String componentPath;

    private Integer behaviorIndex;

    private String methodName;

    private Predicate<Object> filter;

    private Predicate<Object> contextAwareFilter;

    /**
     * Construct.
     * 
     * @param component
     * @param behavior
     * @param method
     */
    public MethodEventSubscription(Component component, Behavior behavior, Method method) {
        componentPath = component.getPageRelativePath();
        behaviorIndex = behavior == null ? null : component.getBehaviorId(behavior);
        Class<?> eventType = method.getParameterTypes()[1];
        Subscribe subscribe = method.getAnnotation(Subscribe.class);
        filter = Predicates.and(Predicates.instanceOf(eventType), createFilter(subscribe.filter()));
        contextAwareFilter = createFilter(subscribe.contextAwareFilter());
        methodName = method.getName();
    }

    @SuppressWarnings("unchecked")
    private static Predicate<Object> createFilter(Class<? extends Predicate<?>> filterClass) {
        try {
            return (Predicate<Object>) filterClass.newInstance();
        } catch (InstantiationException e) {
            throw new WicketRuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new WicketRuntimeException(e);
        }
    }

    /**
     * @return The path of the subscribed component
     */
    public String getComponentPath() {
        return componentPath;
    }

    /**
     * @return The index of the subscribed behavior, or null if the subscription is for the
     *         component itself
     */
    private Integer getBehaviorIndex() {
        return behaviorIndex;
    }

    /**
     * @return The filter on incomming events, a combination of the type and the
     *         {@link Subscribe#filter()} parameter.
     */
    public Predicate<Object> getFilter() {
        return filter;
    }

    /**
     * @return The context ware filter on incomming events, constructed from the
     *         {@link Subscribe#contextAwareFilter()} parameter.
     */
    public Predicate<Object> getContextAwareFilter() {
        return contextAwareFilter;
    }

    /**
     * @return The method that is subscribed
     */
    public String getMethodName() {
        return methodName;
    }

    @Override
    public void call(AjaxRequestTarget target, Object event) {
        if (!getContextAwareFilter().apply(event)) {
            // Filter not applied, do not invoke call.
            return;
        }

        Page page = target.getPage();
        Component component = page.get(getComponentPath());
        Object base = component;
        if (getBehaviorIndex() != null) {
            base = component.getBehaviorById(getBehaviorIndex());
        }

        for (Method curMethod : base.getClass().getMethods()) {
            if (curMethod.isAnnotationPresent(Subscribe.class) && curMethod.getName().equals(getMethodName())) {
                try {
                    curMethod.setAccessible(true);
                    curMethod.invoke(base, target, event);
                } catch (IllegalAccessException e) {
                    throw new WicketRuntimeException(e);
                } catch (IllegalArgumentException e) {
                    throw new WicketRuntimeException(e);
                } catch (InvocationTargetException e) {
                    throw new WicketRuntimeException(e);
                }
            }
        }
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(componentPath, behaviorIndex, methodName);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof MethodEventSubscription) {
            MethodEventSubscription other = (MethodEventSubscription) obj;
            return Objects.equal(componentPath, other.getComponentPath())
                    && Objects.equal(behaviorIndex, other.getBehaviorIndex())
                    && Objects.equal(methodName, other.getMethodName());
        }
        return false;
    }
}