org.directwebremoting.servlet.BaseModule Maven / Gradle / Ivy

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DWR is easy Ajax for Java. It makes it simple to call Java code directly from Javascript. It gets rid of almost all the boilerplate code between the web browser and your Java code. This version 4.0.2 works with Jakarta Servlet 4.0.2.
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package org.directwebremoting.servlet;

import org.directwebremoting.util.LocalUtil;

/**
 * A base class for script modules.
 * @author Mike Wilson [mikewse at hotmail dot com]
 */
public class BaseModule
{
    /**
     * Constructor. Path parameters are supplied for expanding path variables in
     * module paths.
     * @param contextPath ...
     * @param servletPath ...
     * @param separator ..
     */
    public BaseModule(String contextPath, String servletPath, String separator)
    {
        this.contextPath = contextPath.replace("/", separator);
        this.servletPath = servletPath.replace("/", separator);
        this.separator = separator;
    }

    /**
     * Adds the actual module content (script body).
     * @param content ...
     */
    public void addContent(String content)
    {
        this.contentBuf.append(content);
    }

    /**
     * Expands ${contextPath} and ${servletPath} variables in the baseModulePath.
     * @param baseModulePath ...
     * @return module path
     */
    public String expandModulePath(String baseModulePath)
    {
        // Replace variables in baseModulePath according to this scheme
        // (assuming / as separator):
        //   baseModulePath         servletPath        result
        //   ${servletPath}         ""                 ""
        //   ${servletPath}         /dwr               dwr
        //   /${servletPath}        ""                 /
        //   /${servletPath}        /dwr               /dwr
        //   ${servletPath}/abc     ""                 abc
        //   ${servletPath}/abc     /dwr               dwr/abc
        //   /${servletPath}/abc    ""                 /abc
        //   /${servletPath}/abc    /dwr               /dwr/abc
        //   abc/${servletPath}     ""                 abc
        //   abc/${servletPath}     /dwr               abc/dwr
        //   /abc/${servletPath}    ""                 /abc
        //   /abc/${servletPath}    /dwr               /abc/dwr

        // Expand variables in baseModulePath
        String expandedBaseModulePath = baseModulePath.replace("${contextPath}", contextPath).replace("${servletPath}", servletPath);

        // Clean up the result:
        // - remove double separators
        // - remove leading separator if not absolute path
        // - remove trailing separator (but leave leading separator)
        while(expandedBaseModulePath.indexOf(separator + separator) > 0)
        {
            expandedBaseModulePath = expandedBaseModulePath.replaceAll(separator + separator, separator);
        }
        if (!baseModulePath.startsWith(separator) && expandedBaseModulePath.startsWith(separator))
        {
            expandedBaseModulePath = expandedBaseModulePath.substring(separator.length());
        }
        if (expandedBaseModulePath.endsWith(separator) && expandedBaseModulePath.length() > separator.length())
        {
            expandedBaseModulePath = expandedBaseModulePath.substring(0, expandedBaseModulePath.length() - separator.length());
        }

        return expandedBaseModulePath;
    }

    /**
     * Mounts a moduleName onto a baseModulePath and at the same time expanding
     * ${contextPath} and ${servletPath} variables in the baseModulePath. The
     * module path segments in the resulting module name will be separated with
     * the configured separator (typically / or .).
     * @param baseModulePath ...
     * @param moduleName ...
     * @return module name rooted on baseModulePath
     */
    public String expandModulePath(String baseModulePath, String moduleName)
    {
        String expandedModulePath = expandModulePath(baseModulePath);
        String expandedModuleName = moduleName.replaceAll("\\.", separator);
        String sep = "";
        if (LocalUtil.hasLength(expandedModulePath) && LocalUtil.hasLength(expandedModuleName))
        {
            sep = separator;
        }
        return expandedModulePath + sep + expandedModuleName;
    }

    /**
     * The supplied context path used for variable expansion.
     */
    private final String contextPath;

    /**
     * The supplied servlet path used for variable expansion.
     */
    private final String servletPath;

    /**
     * The separator used between module name segments (typically / or .).
     */
    private final String separator;

    /**
     * Module content (script body).
     */
    protected final StringBuilder contentBuf = new StringBuilder();
}