org.trpr.example.service.cep.CEPEngineResource.java Source code

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Here is the source code for org.trpr.example.service.cep.CEPEngineResource.java

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/*
 * Copyright 2012-2015, the original author or authors.
 *
 * Licensed 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.trpr.example.service.cep;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.trpr.platform.impl.task.URIResource;
import org.trpr.platform.spi.task.Resource;

/**
 * The <code>CEPEngineResource</code> class is a CEP Engine {@link Resource} used in processing event stream processing in Trooper.
 * Looks up a CEP engine defined as a Spring Bean and identified by this Resource {@link Resource#getName()} method.
 * 
 * @author Regunath B
 * @version 1.0, 28/09/2012
 */
@SuppressWarnings("rawtypes")
public class CEPEngineResource<T> implements Resource<T>, ApplicationContextAware {

    /** Default serial version UID*/
    private static final long serialVersionUID = 1L;

    /** The name of the CEP Engine bean in the application context that created this Resource or was set on it explicitly */
    public static final String CEP_ENGINE_BEAN_NAME = "cepEngine";

    /** Description for this CEP Engine Resource */
    private static final String CEP_ENGINE_DESCRIPTION = "Trooper CEP Engine";

    /** The Spring app context that created this Resource or was set on it explicitly */
    private ApplicationContext appContext;

    /**
     * Interface method implementation. Checks of a Spring bean by name {@link CEPEngineResource#CEP_ENGINE_BEAN_NAME} exists in the application context
     * set on this class
     * @see org.trpr.platform.spi.task.Resource#exists()
     */
    public boolean exists() {
        return this.appContext.containsBean(((URIResource) this.getSerializedForm()).getSerializedForm());
    }

    /**
     * Interface method implementation. Creates and returns a {@link URIResource}
     * @see org.trpr.platform.spi.task.Resource#getSerializedForm()
     */
    @SuppressWarnings({ "unchecked" })
    public T getSerializedForm() {
        return (T) new URIResource<T>(this);
    }

    /**
     * Interface method implementation. Returns {@link #CEP_ENGINE_BEAN_NAME}
     * @see org.trpr.platform.spi.task.Resource#getName()
     */
    public String getName() {
        return CEPEngineResource.CEP_ENGINE_BEAN_NAME;
    }

    /**
     * Interface method implementation. Return static description text contained in {@link #CEP_ENGINE_DESCRIPTION}
     * @see org.trpr.platform.spi.task.Resource#getDescription()
     */
    public String getDescription() {
        return CEPEngineResource.CEP_ENGINE_DESCRIPTION;
    }

    /**
     * Interface method implementation. Returns true if the serialized forms match
     * @see org.trpr.platform.spi.task.Resource#equals(org.trpr.platform.spi.task.Resource)
     */
    public boolean equals(Resource<T> resource) {
        return this.getSerializedForm().equals(resource.getSerializedForm());
    }

    /**
     * Gets the CEP Engine bean from the Spring Application context using the serialized form.
     * @return a CEP Engine implementation
     */
    public Object getObject() throws Exception {
        return this.appContext.getBean(((URIResource) this.getSerializedForm()).getSerializedForm());
    }

    /**
     * Interface method implementation. Sets the ApplicationContext which has the CEP Engine bean
     * @see org.springframework.context.ApplicationContextAware#setApplicationContext(org.springframework.context.ApplicationContext)
     */
    public void setApplicationContext(ApplicationContext appContext) throws BeansException {
        this.appContext = appContext;
    }

}