blueprint.sdk.util.config.Config Maven / Gradle / Ivy

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/*
 License:

 blueprint-sdk is licensed under the terms of Eclipse Public License(EPL) v1.0
 (http://www.eclipse.org/legal/epl-v10.html)


 Distribution:

 Maven Central - https://search.maven.org/artifact/io.github.lempel/blueprint-sdk
 MVN Repository - https://mvnrepository.com/artifact/io.github.lempel/blueprint-sdk
 */

package blueprint.sdk.util.config;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPathExpressionException;

import org.apache.commons.jxpath.JXPathContext;
import org.apache.commons.jxpath.Pointer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Node;

import blueprint.sdk.util.JXPathHelper;
import blueprint.sdk.util.Validator;

/**
 * Configuration Handler
 *
 * @author [email protected]
 * @since 2013. 6. 18.
 */
public class Config {
    /**
     * logger
     */
    private static final Logger L = LoggerFactory.getLogger(Config.class);

    /**
     * uri of configuration
     */
    private String uri;

    private DocumentBuilder builder;

    /**
     * root Node of config xml
     */
    private Node root;

    /**
     * root as JXPathContext
     */
    @SuppressWarnings("WeakerAccess")
    protected JXPathContext context;

    /**
     * Constructor
     */
    public Config() {
        // NO-OP
    }

    /**
     * Constructor
     *
     * @param root Document or Node of config
     */
    @SuppressWarnings("WeakerAccess")
    public Config(Node root) {
        this.root = root;
    }

    /**
     * @return configuration's uri
     */
    public String getUri() {
        return uri;
    }

    /**
     * @param uri path/uri of config xml
     * @throws ConfigException load failure
     */
    public void load(String uri) throws ConfigException {
        synchronized (this) {
            this.uri = uri;

            if (builder == null) {
                try {
                    builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
                } catch (ParserConfigurationException e) {
                    throw new ConfigException("XML parser error", e);
                }
            }
        }

        try {
            root = builder.parse(uri);
            context = JXPathContext.newContext(root);
        } catch (Exception e) {
            throw new ConfigException("Can't parse config xml", e);
        }

        String configName = JXPathHelper.evaluate("config/@name", context);
        if (Validator.isEmpty(configName)) {
            configName = "no-name";
        }

        L.info("configuration '" + configName + "' is loaded");
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return null or String value
     */
    public String getString(String xpath) {
        String result = JXPathHelper.evaluate(xpath, context);
        result = resolveProperty(result);

        warnEmptyValue(xpath, result);

        return result;
    }

    /**
     * Print warning message (actual log level is INFO) if designated value is
     * empty.
     *
     * @param xpath XPath to evaluate
     * @param result value to check
     */
    @SuppressWarnings("WeakerAccess")
    protected void warnEmptyValue(String xpath, String result) {
        if (result == null || result.isEmpty()) {
            L.info("evaluated result of '" + xpath + "' is empty");
        }
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return boolean value
     * @throws XPathExpressionException
     */
    public boolean getBoolean(String xpath) throws XPathExpressionException {
        try {
            return Boolean.parseBoolean(getString(xpath));
        } catch (NumberFormatException e) {
            throw new XPathExpressionException("evaluated result of '" + xpath + "' is not an Integer");
        }
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return int value
     * @throws XPathExpressionException
     */
    public int getInt(String xpath) throws XPathExpressionException {
        try {
            return Integer.parseInt(getString(xpath));
        } catch (NumberFormatException e) {
            throw new XPathExpressionException("evaluated result of '" + xpath + "' is not an Integer");
        }
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return values as String[]
     */
    public String[] getStringArray(String xpath) {
        List result = new ArrayList<>(10);

        Iterator nodeIter = JXPathHelper.evaluateIteratorPointers(xpath, context);
        while (nodeIter.hasNext()) {
            Pointer nodePtr = nodeIter.next();

            String value = (String) nodePtr.getValue();
            value = resolveProperty(value);
            result.add(value);
        }

        if (result.size() == 0) {
            warnEmptyValue(xpath, null);
        }

        return result.toArray(new String[result.size()]);
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return values as Boolean[]
     * @throws XPathExpressionException
     */
    public Boolean[] getBooleanArray(String xpath) throws XPathExpressionException {
        List result = new ArrayList<>(10);

        Iterator nodeIter = JXPathHelper.evaluateIteratorPointers(xpath, context);
        while (nodeIter.hasNext()) {
            Pointer nodePtr = nodeIter.next();

            String value = (String) nodePtr.getValue();
            value = resolveProperty(value);
            try {
                result.add(Boolean.parseBoolean(value));
            } catch (NumberFormatException e) {
                throw new XPathExpressionException("evaluated result of '" + xpath + "' is not a Boolean");
            }
        }

        if (result.size() == 0) {
            warnEmptyValue(xpath, null);
        }

        return result.toArray(new Boolean[result.size()]);
    }

    /**
     * Get value from given XPath
     *
     * @param xpath XPath to evaluate
     * @return values Integer[]
     * @throws XPathExpressionException
     */
    public Integer[] getIntArray(String xpath) throws XPathExpressionException {
        List result = new ArrayList<>(10);

        Iterator nodeIter = JXPathHelper.evaluateIteratorPointers(xpath, context);
        while (nodeIter.hasNext()) {
            Pointer nodePtr = nodeIter.next();

            String value = (String) nodePtr.getValue();
            value = resolveProperty(value);
            try {
                result.add(Integer.parseInt(value));
            } catch (NumberFormatException e) {
                throw new XPathExpressionException("evaluated result of '" + xpath + "' is not an Integer");
            }
        }

        if (result.size() == 0) {
            warnEmptyValue(xpath, null);
        }

        return result.toArray(new Integer[result.size()]);
    }

    /**
     * Replace '$' enclosed value with system property.
     *
     * @param value XPath to evaluate
     * @return system property or value itself(no such property)
     */
    @SuppressWarnings("WeakerAccess")
    protected String resolveProperty(String value) {
        String result = value;

        if (!Validator.isEmpty(value) && value.charAt(0) == '$' && value.endsWith("$")) {
            String key = value.substring(1, value.length() - 1);

            Properties props = System.getProperties();
            if (props.containsKey(key)) {
                result = props.getProperty(key);
            }
        }

        return result;
    }
}