LifecycleEndPointAnalyzer.java

/**
 * Copyright (c) 2009-2011 VMware, Inc. All Rights Reserved.
 *
 * 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 com.springsource.insight.plugin.servlet;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import com.springsource.insight.intercept.endpoint.AbstractEndPointAnalyzer;
import com.springsource.insight.intercept.endpoint.EndPointAnalysis;
import com.springsource.insight.intercept.endpoint.EndPointName;
import com.springsource.insight.intercept.operation.Operation;
import com.springsource.insight.intercept.operation.OperationType;
import com.springsource.insight.intercept.trace.Frame;
import com.springsource.insight.intercept.trace.Trace;

/**
 * Locates lifecycle endpoints within Traces.
 * <p/>
 * If a LifecycleOperation is detected in the root frame, an endpoint analysis
 * will be returned. The score of the analysis will always be {@link LifecycleEndPointAnalyzer#ANALYSIS_SCORE}, and its endpoint
 * key/label will be based on the lifecycle event.
 */
public class LifecycleEndPointAnalyzer extends AbstractEndPointAnalyzer {
    /**
     * The <U>static</U> score assigned to the generated endpoints.
     * <B>Note:</B> we assign a rather high value since we want this endpoint
     * to "trump" others with high probability. However, it will
     * do so only if the <U>root</U> frame is a lifecycle one
     *
     * @see #getScoringFrame(Trace)
     * @see #validateScoringFrame(Frame)
     */
    public static final int ANALYSIS_SCORE = 50;

    public static final OperationType SERVLET_LISTENER_TYPE = OperationType.valueOf("servlet-listener");
    public static final OperationType LIFECYCLE_TYPE_TYPE = OperationType.APP_LIFECYCLE;
    public static final EndPointName ENDPOINT_NAME = EndPointName.valueOf("lifecycle");
    public static final String ENDPOINT_LABEL = "App Lifecycle";
    /**
     * The {@link List} of {@link OperationType}-s that mark a lifecycle frame
     */
    public static final List<OperationType> OPS = Collections.unmodifiableList(Arrays.asList(SERVLET_LISTENER_TYPE, LIFECYCLE_TYPE_TYPE));
    private static final LifecycleEndPointAnalyzer INSTANCE = new LifecycleEndPointAnalyzer();

    private LifecycleEndPointAnalyzer() {
        super(OPS);
    }

    public static final LifecycleEndPointAnalyzer getInstance() {
        return INSTANCE;
    }

    @Override
    public Frame getScoringFrame(Trace trace) {
        Frame root = trace.getRootFrame();
        if (validateScoringFrame(root) == null) {
            return null;
        } else {
            return root;
        }
    }

    @Override
    protected int getDefaultScore(int depth) {
        return ANALYSIS_SCORE;
    }

    @Override
    protected OperationType validateScoringFrame(Frame frame) {
        if ((frame == null) || (!frame.isRoot())) {
            return null;
        } else {
            return super.validateScoringFrame(frame);
        }
    }

    @Override
    protected EndPointAnalysis makeEndPoint(Frame lifecycleFrame, int depth) {
        Operation op = lifecycleFrame.getOperation();
        String endPointExample = op.get("event", String.class);

        return new EndPointAnalysis(ENDPOINT_NAME, ENDPOINT_LABEL, endPointExample, getOperationScore(op, depth), op);
    }
}