com.adobe.granite.ui.components.ExpressionHelper Maven / Gradle / Ivy

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 * ADOBE CONFIDENTIAL
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 *
 *  Copyright 2013 Adobe Systems Incorporated
 *  All Rights Reserved.
 *
 * NOTICE:  All information contained herein is, and remains
 * the property of Adobe Systems Incorporated and its suppliers,
 * if any.  The intellectual and technical concepts contained
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package com.adobe.granite.ui.components;

import java.util.Locale;

import javax.servlet.ServletRequest;
import javax.servlet.ServletRequestWrapper;
import javax.servlet.jsp.PageContext;

import org.apache.sling.api.SlingHttpServletRequest;

/**
 * A helper to deal with EL easier.
 */
public class ExpressionHelper {
    private ExpressionResolver resolver;

    private SlingHttpServletRequest request;

    public ExpressionHelper(ExpressionResolver resolver, PageContext pageContext) {
        this(resolver, toSlingRequest(pageContext.getRequest()));
    }

    public ExpressionHelper(ExpressionResolver resolver, SlingHttpServletRequest servletRequest) {
        this.resolver = resolver;
        this.request = servletRequest;
    }

    /**
     * Resolves the given expression as string. Request's locale will be used.
     * @param expression the expression to be resolved
     * @return the resolved expression as a string
     */
    public String getString(String expression) {
        return get(expression, String.class);
    }

    /**
     * Resolves the given expression as string, with the given locale.
     * @param expression the expression to be resolved
     * @param locale the locale
     * @return the resolved expression as a string
     */
    public String getString(String expression, Locale locale) {
        return get(expression, locale, String.class);
    }

    /**
     * Resolves the given expression as boolean. Request's locale will be used.
     * @param expression the expression to be resolved
     * @return the resolved expression as a boolean
     */
    public boolean getBoolean(String expression) {
        return get(expression, Boolean.class);
    }

    /**
     * Resolves the given expression as boolean, with the given locale.
     * @param expression the expression to be resolved
     * @param locale the locale
     * @return the resolved expression as a boolean
     */
    public boolean getBoolean(String expression, Locale locale) {
        return get(expression, locale, Boolean.class);
    }

    /**
     * Resolves the given expression. Request's locale will be used.
     * @param expression the expression to be resolved
     * @param expectedType the expected type of the resolved expression
     * @param  the type of the resolved expression
     * @return the resolved expression
     */
    public  T get(String expression, Class expectedType) {
        return get(expression, request.getLocale(), expectedType);
    }

    /**
     * Resolves the given expression, with the given locale.
     * @param expression the expression to be resolved
     * @param locale the locale
     * @param expectedType the expected type of the resolved expression
     * @param  the type of the resolved expression
     * @return the resolved expression
     */
    public  T get(String expression, Locale locale, Class expectedType) {
        if (expression == null) return null;

        return resolver.resolve(expression, locale, expectedType, request);
    }

    private static SlingHttpServletRequest toSlingRequest(ServletRequest req) {
        while (!(req instanceof SlingHttpServletRequest)) {
            if (req instanceof ServletRequestWrapper) {
                req = ((ServletRequestWrapper) req).getRequest();
            } else {
                throw new IllegalStateException("request wrong class");
            }
        }

        return (SlingHttpServletRequest) req;
    }
}