org.fabrican.extension.variable.provider.VariableProviderProxy.java Source code

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Here is the source code for org.fabrican.extension.variable.provider.VariableProviderProxy.java

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/*
 * Copyright (c) 2013 TIBCO Software Inc. All Rights Reserved.
 *
 * Use is subject to the terms of the TIBCO license terms accompanying the download of this code.
 * In most instances, the license terms are contained in a file named license.txt.
 */
package org.fabrican.extension.variable.provider;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.Properties;

import org.apache.commons.jexl2.Expression;
import org.apache.commons.jexl2.JexlContext;
import org.apache.commons.jexl2.JexlEngine;
import org.apache.commons.jexl2.MapContext;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONTokener;

import com.datasynapse.fabric.admin.info.ComponentInfo;
import com.datasynapse.fabric.admin.info.FabricEngineInfo;
import com.datasynapse.fabric.admin.info.StackInfo;
import com.datasynapse.fabric.broker.userartifact.variable.AbstractDynamicVariableProvider;
import com.datasynapse.fabric.util.ContainerUtils;

public class VariableProviderProxy extends AbstractDynamicVariableProvider {

    private String serverURL;
    private String primaryKey;
    private String secondaryKey;
    private JexlEngine jexl = new JexlEngine();

    public Properties getVariables(FabricEngineInfo engineInfo, StackInfo stackInfo, ComponentInfo componentInfo) {

        MapContext jc = new MapContext();
        jc.set("engineInfo", engineInfo);
        jc.set("stackInfo", stackInfo);
        jc.set("componentInfo", componentInfo);
        String p = evaluate(getPrimaryKey(), jc);
        String s = evaluate(getSecondaryKey(), jc);
        ;

        if (getServerURL() == null) {
            throw new IllegalArgumentException("serverURL is not set");
        }
        String u = getServerURL();
        try {
            u += "?primary=" + (p == null ? "" : URLEncoder.encode(p.trim(), "utf-8"));
            u += "&secondary=" + (s == null ? "" : URLEncoder.encode(s.trim(), "utf-8"));
        } catch (UnsupportedEncodingException e) {
            // we always have "UTF-8" but anyway
            throw new RuntimeException("utf-8 not supported", e);
        }
        InputStream is = null;
        try {
            URL url = new URL(u);
            URLConnection c = url.openConnection();
            is = c.getInputStream();
            JSONTokener tokener = new JSONTokener(new InputStreamReader(is, "utf-8"));
            JSONObject jObj = new JSONObject(tokener);
            Properties r = new Properties();
            @SuppressWarnings("unchecked")
            Iterator<String> keys = jObj.keys();
            while (keys.hasNext()) {
                String k = keys.next();
                r.put(k, jObj.getString(k));
            }
            String msg = "no variables";
            if (r.size() > 0) {
                msg = r.toString();
            }
            ContainerUtils.getLogger(this).fine(
                    "Provided " + msg + " to Engine " + engineInfo.getUsername() + "-" + engineInfo.getInstance());
            return r;
        } catch (IOException ioe) {
            throw new RuntimeException("failed to connection to web server", ioe);
        } catch (JSONException je) {
            throw new RuntimeException("failed to parse response from web server", je);
        } finally {
            try {
                if (is != null) {
                    is.close();
                }
            } catch (Exception e) {

            }
        }
    }

    private String evaluate(String propExpr, JexlContext jc) {
        if (propExpr != null) {
            Expression e = jexl.createExpression(propExpr);
            return (String) e.evaluate(jc);
        } else {
            return null;
        }
    }

    public void destroy() {
    }

    public void init() throws Exception {
    }

    public String getServerURL() {
        return serverURL;
    }

    public void setServerURL(String serverURL) {
        this.serverURL = serverURL;
    }

    public String getPrimaryKey() {
        return primaryKey;
    }

    public void setPrimaryKey(String primaryKey) {
        this.primaryKey = primaryKey;
    }

    public String getSecondaryKey() {
        return secondaryKey;
    }

    public void setSecondaryKey(String secondaryKey) {
        this.secondaryKey = secondaryKey;
    }
}