com.opengamma.component.AbstractComponentConfigLoader.java Source code

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Here is the source code for com.opengamma.component.AbstractComponentConfigLoader.java

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/**
 * Copyright (C) 2009 - present by OpenGamma Inc. and the OpenGamma group of companies
 *
 * Please see distribution for license.
 */
package com.opengamma.component;

import java.io.IOException;
import java.util.List;
import java.util.concurrent.ConcurrentMap;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.core.io.Resource;

import com.opengamma.OpenGammaRuntimeException;

/**
 * Abstract class for loading component configuration.
 */
public abstract class AbstractComponentConfigLoader {

    /**
     * The logger.
     */
    private final ComponentLogger _logger;
    /**
     * The set of properties being built up.
     */
    private final ConcurrentMap<String, String> _properties;

    /**
     * Creates an instance.
     * 
     * @param logger  the logger, not null
     * @param properties  the properties in use, not null
     */
    public AbstractComponentConfigLoader(ComponentLogger logger, ConcurrentMap<String, String> properties) {
        _logger = logger;
        _properties = properties;
    }

    //-------------------------------------------------------------------------
    /**
     * Gets the logger.
     * 
     * @return the logger, not null
     */
    public ComponentLogger getLogger() {
        return _logger;
    }

    /**
     * Gets the properties.
     * 
     * @return the properties, not null
     */
    public ConcurrentMap<String, String> getProperties() {
        return _properties;
    }

    //-------------------------------------------------------------------------
    /**
     * Resolves any ${property} references in the value.
     * 
     * @param value  the value to resolve, not null
     * @param lineNum  the line number, for error messages
     * @return the resolved value, not null
     */
    protected String resolveProperty(String value, int lineNum) {
        String variable = findVariable(value);
        while (variable != null) {
            if (_properties.containsKey(variable) == false) {
                throw new OpenGammaRuntimeException(
                        "Variable expansion not found: ${" + variable + "}, line " + lineNum);
            }
            value = StringUtils.replaceOnce(value, "${" + variable + "}", _properties.get(variable));
            variable = findVariable(value);
        }
        return value;
    }

    /**
     * Finds a variable to replace.
     * 
     * @param value  the value to search, not null
     * @return the variable, null if not found
     */
    private String findVariable(String value) {
        int start = value.lastIndexOf("${");
        if (start >= 0) {
            start += 2;
            int end = value.indexOf("}", start);
            if (end >= 0) {
                return value.substring(start, end);
            }
        }
        return null;
    }

    /**
     * Reads lines from the resource.
     * 
     * @param resource  the resource to read, not null
     * @return the lines, not null
     */
    protected List<String> readLines(Resource resource) {
        try {
            return IOUtils.readLines(resource.getInputStream(), "UTF8");
        } catch (IOException ex) {
            throw new OpenGammaRuntimeException("Unable to read resource: " + resource, ex);
        }
    }

}