edu.utah.further.core.util.text.PlaceHolderResolverImpl.java Source code

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Here is the source code for edu.utah.further.core.util.text.PlaceHolderResolverImpl.java

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/**
 * Copyright (C) [2013] [The FURTHeR Project]
 *
 * 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 edu.utah.further.core.util.text;

import static edu.utah.further.core.api.text.ToStringCustomStyles.SHORT_WITH_SPACES_STYLE;
import static org.slf4j.LoggerFactory.getLogger;
import static org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.DEFAULT_PLACEHOLDER_PREFIX;
import static org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.DEFAULT_PLACEHOLDER_SUFFIX;
import static org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.DEFAULT_VALUE_SEPARATOR;

import java.util.Properties;

import org.apache.commons.lang.builder.ToStringBuilder;
import org.slf4j.Logger;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.stereotype.Service;
import org.springframework.util.PropertyPlaceholderHelper;

import edu.utah.further.core.api.exception.ApplicationException;
import edu.utah.further.core.api.lang.CoreUtil;
import edu.utah.further.core.api.text.PlaceHolderResolver;

/**
 * A utility service that resolves place holders in strings. It harnesses Spring's
 * property place holder replacement facility. The only difference between this class and
 * Spring's {@link PropertyPlaceholderConfigurer} is that the former is intended to
 * directly process strings, and the latter processes spring context bean definitions.
 * <p>
 * This implementation class is built for extension.
 * -----------------------------------------------------------------------------------<br>
 * (c) 2008-2013 FURTHeR Project, Health Sciences IT, University of Utah<br>
 * Contact: {@code <further@utah.edu>}<br>
 * Biomedical Informatics, 26 South 2000 East<br>
 * Room 5775 HSEB, Salt Lake City, UT 84112<br>
 * Day Phone: 1-801-581-4080<br>
 * -----------------------------------------------------------------------------------
 * 
 * @author Oren E. Livne {@code <oren.livne@utah.edu>}
 * @version Apr 26, 2010
 */
@Service("placeHolderResolver")
public class PlaceHolderResolverImpl implements PlaceHolderResolver {
    // ========================= CONSTANTS =================================

    /**
     * A logger that helps identify this class' printouts.
     */
    @SuppressWarnings("unused")
    private static final Logger log = getLogger(PlaceHolderResolverImpl.class);

    // ========================= DEPENDENCIES ==============================

    /**
     * Default properties to use as place-holders.
     */
    private Properties defaultPlaceHolders;

    // ========================= FIELDS ====================================

    private final PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(DEFAULT_PLACEHOLDER_PREFIX,
            DEFAULT_PLACEHOLDER_SUFFIX, DEFAULT_VALUE_SEPARATOR, true);

    // ========================= CONSTRUCTORS ==============================

    /**
     * Initialize a resolver. By default, no place holders are declared.
     */
    public PlaceHolderResolverImpl() {
        setDefaultPlaceHolders(new Properties());
    }

    // ========================= IMPLEMENTATION: Object ====================

    /**
     * @return
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return new ToStringBuilder(this, SHORT_WITH_SPACES_STYLE).append("defaultPlaceHolders", defaultPlaceHolders)
                .toString();
    }

    // ========================= METHODS ===================================

    /**
     * @param strVal
     * @return
     * @see edu.utah.further.core.api.text.PlaceHolderResolver#resolvePlaceholders(java.lang.String)
     */
    @Override
    public String resolvePlaceholders(final String strVal) {
        return helper.replacePlaceholders(strVal, defaultPlaceHolders);
    }

    /**
     * Resolve all place holders in a string. Allows to override the default place holders
     * for this specific string.
     * 
     * @param strVal
     *            original string
     * @param overriddenPlaceholders
     *            map of key-value place holders to use. Is overlaid over the default
     *            place holder map, potentially overriding the default values with
     *            identical keys in both maps
     * @return string with place holders replaced with their values
     * @throws ApplicationException
     *             if unresolved or circular place holder references are detected
     */
    @Override
    public String resolvePlaceholders(final String strVal, final Properties overriddenPlaceholders) {
        if (strVal == null) {
            return strVal;
        }

        final Properties props = new Properties(defaultPlaceHolders);
        props.putAll(overriddenPlaceholders);
        return helper.replacePlaceholders(strVal, props);
    }

    // ========================= GET & SET =================================

    /**
     * Return the defaultPlaceHolders property.
     * 
     * @return the defaultPlaceHolders
     */
    @Override
    public Properties getDefaultPlaceHolders() {
        // Make a defensive copy
        return CoreUtil.newPropertiesCopy(defaultPlaceHolders);
    }

    /**
     * Set a new value for the defaultPlaceHolders property.
     * 
     * @param defaultPlaceHolders
     *            the defaultPlaceHolders to set
     */
    @Override
    public final void setDefaultPlaceHolders(final Properties defaultPlaceHolders) {
        // Make a defensive copy
        this.defaultPlaceHolders = CoreUtil.newPropertiesCopy(defaultPlaceHolders);
    }
}