org.jmxtrans.embedded.util.json.PlaceholderEnabledJsonNodeFactory.java Source code

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Here is the source code for org.jmxtrans.embedded.util.json.PlaceholderEnabledJsonNodeFactory.java

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/*
 * Copyright (c) 2010-2013 the original author or authors
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 * 
 */
package org.jmxtrans.embedded.util.json;

import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.TextNode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Property placeholder / substitution enabled {@link JsonNodeFactory}.
 *
 * Each JSON text value is processed by the {@link PropertyPlaceholderResolver}before building a {@linkplain TextNode}.
 *
 * Inspired by <a href="http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/html/beans.html#beans-factory-placeholderconfigurer">
 * Spring Framework PropertyPlaceHolder</a> and by
 * <a href="http://commons.apache.org/digester/guide/substitution.html">Jakarta Digester Substitution</a>.
 *
 * @author <a href="mailto:cleclerc@xebia.fr">Cyrille Le Clerc</a>
 */
public class PlaceholderEnabledJsonNodeFactory extends JsonNodeFactory {

    private static final long serialVersionUID = 1L;

    private transient final Logger logger = LoggerFactory.getLogger(getClass());

    private PropertyPlaceholderResolver resolver = new PropertyPlaceholderResolver();

    /**
     * Main constructor
     *
     * <p>The only argument to this constructor is a boolean telling whether
     * {@link com.fasterxml.jackson.databind.node.DecimalNode} instances must be built with exact representations of
     * {@link java.math.BigDecimal} instances.</p>
     *
     * <p>This has quite an influence since, for instance, a BigDecimal (and,
     * therefore, a DecimalNode) constructed from input string {@code "1.0"} and
     * another constructed with input string {@code "1.00"} <b>will not</b> be
     * equal, since their scale differs (1 in the first case, 2 in the second
     * case).</p>
     *
     * <p>Note that setting the argument to {@code true} does <i>not</i>
     * guarantee a strict inequality between JSON representations: input texts
     * {@code "0.1"} and {@code "1e-1"}, for instance, yield two equivalent
     * BigDecimal instances since they have the same scale (1).</p>
     *
     * <p>The no-arg constructor (and the default {@link #instance}) calls this
     * constructor with {@code false} as an argument.</p>
     *
     * @param bigDecimalExact see description
     * @see java.math.BigDecimal
     */
    public PlaceholderEnabledJsonNodeFactory(boolean bigDecimalExact) {
        super(bigDecimalExact);
    }

    /**
     * Default constructor
     *
     * <p>This calls {@link #PlaceholderEnabledJsonNodeFactory(boolean)} with {@code false}
     * as an argument.</p>
     */
    public PlaceholderEnabledJsonNodeFactory() {
        super();
    }

    @Override
    public TextNode textNode(String text) {
        String resolvedText = (text == null) ? null : resolver.resolveString(text);
        if (logger.isInfoEnabled()) {
            if (text == null || text.equals(resolvedText)) {
                logger.debug("Resolve '{}' into '{}'", text, resolvedText);
            } else {
                logger.info("Resolve '{}' into '{}'", text, resolvedText);
            }
        }
        return super.textNode(resolvedText);
    }
}