com.facebook.buck.parcelable.Parser.java Source code

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Here is the source code for com.facebook.buck.parcelable.Parser.java

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/*
 * Copyright 2012-present Facebook, Inc.
 *
 * 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 com.facebook.buck.parcelable;

import com.facebook.buck.util.XmlDomParser;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

import java.io.File;
import java.io.IOException;

import javax.annotation.Nullable;

public class Parser {

    /** Utility class: do not instantiate. */
    private Parser() {
    }

    public static ParcelableClass parse(File xml) throws IOException {
        Document doc = XmlDomParser.parse(xml);

        // packageName, className, creatorClass
        Element classElement = (Element) doc.getElementsByTagName("class").item(0);
        String classNameAttr = getAttribute(classElement, "name");
        int splitIndex = classNameAttr.lastIndexOf('.');
        String packageName = classNameAttr.substring(0, splitIndex);
        String className = classNameAttr.substring(splitIndex + 1);
        String creatorClassName = getAttribute(classElement, "creatorClass");

        // imports
        Element importsElement = (Element) doc.getElementsByTagName("imports").item(0);
        String importsText = importsElement.getTextContent();
        Iterable<String> imports = Splitter.on('\n').omitEmptyStrings().trimResults().split(importsText);

        // defaultFieldVisibility
        Element fieldsElement = (Element) doc.getElementsByTagName("fields").item(0);
        String defaultFieldVisibility = getAttribute(fieldsElement, "defaultVisibility");
        if (defaultFieldVisibility == null) {
            defaultFieldVisibility = "private";
        }

        // fields
        ImmutableList.Builder<ParcelableField> fields = ImmutableList.builder();
        NodeList fieldNodes = fieldsElement.getElementsByTagName("field");
        for (int i = 0; i < fieldNodes.getLength(); i++) {
            Element fieldElement = (Element) fieldNodes.item(i);
            ParcelableField field = new ParcelableField(escapeJavaType(getAttribute(fieldElement, "type")),
                    getAttribute(fieldElement, "name"), getBooleanAttribute(fieldElement, "mutable"),
                    getAttribute(fieldElement, "visibility"), getAttribute(fieldElement, "jsonProperty"),
                    getAttribute(fieldElement, "defaultValue"));
            fields.add(field);
        }

        return new ParcelableClass(packageName, imports, className,
                creatorClassName == null ? className : creatorClassName, defaultFieldVisibility, fields.build(),
                getAttribute(classElement, "extends"), getAttribute(classElement, "superParams"));
    }

    /**
     * We allow { and } to be used in place of &lt; and &gt; for Java generics in our XML
     * descriptor files.
     */
    private static String escapeJavaType(String type) {
        return type.replace('{', '<').replace('}', '>');
    }

    /**
     * Return null if the attribute is not present rather than the empty string.
     */
    @Nullable
    private static String getAttribute(Element element, String attributeName) {
        if (element.hasAttribute(attributeName)) {
            return element.getAttribute(attributeName);
        } else {
            return null;
        }
    }

    private static boolean getBooleanAttribute(Element element, String attributeName) {
        String value = getAttribute(element, attributeName);
        return value != null ? Boolean.parseBoolean(value) : false;
    }
}