com.sun.faces.util.copier.CopierUtils Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of jakarta.faces-api Show documentation
Jakarta Faces defines an MVC framework for building user interfaces for web applications, including UI components, state management, event handing, input validation, page navigation, and support for internationalization and accessibility.
There is a newer version: 4.1.0
Show newest version
/*
 * Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.faces.util.copier;

import static com.sun.faces.util.ReflectionUtils.instance;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.faces.context.FacesContext;

public class CopierUtils {
    
    private static final String ERROR_COPIER_NAME = "The copier name should be a Java valid simple/qualified name.";
    private static final String COPIER_PREFIX = "com.sun.faces.util.copier.";
    
    private final static Set keywords;

    static {
        Set s = new HashSet();
        String[] kws = {
            "abstract", "continue", "for", "new", "switch",
            "assert", "default", "if", "package", "synchronized",
            "boolean", "do", "goto", "private", "this",
            "break", "double", "implements", "protected", "throw",
            "byte", "else", "import", "public", "throws",
            "case", "enum", "instanceof", "return", "transient",
            "catch", "extends", "int", "short", "try",
            "char", "final", "interface", "static", "void",
            "class", "finally", "long", "strictfp", "volatile",
            "const", "float", "native", "super", "while",
            // literals
            "null", "true", "false"
        };
        for (String kw : kws) {
            s.add(kw);
        }
        keywords = Collections.unmodifiableSet(s);
    }    
    
    public static Copier getCopier(FacesContext context, String copierType) {
        Copier copier = null;

        if (!isEmpty(copierType)) {

            // TODO: or should validate only against {"MultiStrategyCopier", "SerializationCopier",
            // "NewInstanceCopier", "CopyCtorCopier", "CloneCopier"} strings / enum
            
            if (isCopierTypeSimpleName(copierType)) {                
                copierType = COPIER_PREFIX.concat(copierType);
            } else if (!isName(copierType)) {
                throw new IllegalArgumentException(ERROR_COPIER_NAME);
            }

            Object expressionResult = evaluateExpressionGet(context, copierType);

            if (expressionResult instanceof Copier) {
                copier = (Copier) expressionResult;
            } else if (expressionResult instanceof String) {
                copier = instance((String) expressionResult);
            }
        }

        if (copier == null) {
            copier = new MultiStrategyCopier();
        }
        
        return copier;
    }

    @SuppressWarnings("unchecked")
    private static  T evaluateExpressionGet(FacesContext context, String expression) {
        if (expression == null) {
            return null;
        }

        return (T) context.getApplication().evaluateExpressionGet(context, expression, Object.class);
    }

    private static boolean isCopierTypeSimpleName(String copierType) {
        return (isIdentifier(copierType) && !(isKeyword(copierType)));
    }

    // maybe the following four methods should be moved in com.sun.faces.util   
    private static boolean isEmpty(String string) {
        return string == null || string.isEmpty();
    }

    private static boolean isName(CharSequence name) {
        String id = name.toString();

        for (String s : id.split("\\.", -1)) {
            if (!isIdentifier(s) || isKeyword(s)) {
                return false;
            }
        }
        return true;
    }

    private static boolean isIdentifier(CharSequence name) {
        String id = name.toString();

        if (id.length() == 0) {
            return false;
        }
        int cp = id.codePointAt(0);
        if (!Character.isJavaIdentifierStart(cp)) {
            return false;
        }
        for (int i = Character.charCount(cp);
                i < id.length();
                i += Character.charCount(cp)) {
            cp = id.codePointAt(i);
            if (!Character.isJavaIdentifierPart(cp)) {
                return false;
            }
        }
        return true;
    }

    private static boolean isKeyword(CharSequence s) {
        String keywordOrLiteral = s.toString();
        return keywords.contains(keywordOrLiteral);
    }

}