org.sonar.api.utils.UriReader.java Source code

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Here is the source code for org.sonar.api.utils.UriReader.java

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/*
 * Sonar, open source software quality management tool.
 * Copyright (C) 2008-2012 SonarSource
 * mailto:contact AT sonarsource DOT com
 *
 * Sonar is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * Sonar is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Sonar; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
 */
package org.sonar.api.utils;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Throwables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.io.Files;
import org.sonar.api.BatchComponent;
import org.sonar.api.ServerComponent;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.nio.charset.Charset;
import java.util.List;
import java.util.Locale;
import java.util.Map;

/**
 * Reads different types of URI. Supported schemes are http and file.
 *
 * @since 3.2
 */
public class UriReader implements BatchComponent, ServerComponent {

    private final Map<String, SchemeProcessor> processorsByScheme = Maps.newHashMap();

    public UriReader(SchemeProcessor[] processors) {
        List<SchemeProcessor> allProcessors = Lists.asList(new FileProcessor(), processors);
        for (SchemeProcessor processor : allProcessors) {
            for (String scheme : processor.getSupportedSchemes()) {
                processorsByScheme.put(scheme.toLowerCase(Locale.ENGLISH), processor);
            }
        }
    }

    /**
     * Reads all bytes from uri. It throws an unchecked exception if an error occurs.
     */
    public byte[] readBytes(URI uri) {
        return searchForSupportedProcessor(uri).readBytes(uri);
    }

    /**
     * Reads all characters from uri, using the given character set.
     * It throws an unchecked exception if an error occurs.
     */
    public String readString(URI uri, Charset charset) {
        return searchForSupportedProcessor(uri).readString(uri, charset);
    }

    /**
     * Returns a detailed description of the given uri. For example HTTP URIs are completed
     * with the configured HTTP proxy.
     */
    public String description(URI uri) {
        SchemeProcessor reader = searchForSupportedProcessor(uri);

        return reader.description(uri);
    }

    @VisibleForTesting
    SchemeProcessor searchForSupportedProcessor(URI uri) {
        SchemeProcessor processor = processorsByScheme.get(uri.getScheme().toLowerCase(Locale.ENGLISH));
        Preconditions.checkArgument(processor != null, "URI schema is not supported: " + uri.getScheme());
        return processor;
    }

    abstract static class SchemeProcessor {
        abstract String[] getSupportedSchemes();

        abstract byte[] readBytes(URI uri);

        abstract String readString(URI uri, Charset charset);

        abstract String description(URI uri);
    }

    /**
     * This implementation is not exposed in API and is kept private.
     */
    private static class FileProcessor extends SchemeProcessor {

        @Override
        public String[] getSupportedSchemes() {
            return new String[] { "file" };
        }

        @Override
        byte[] readBytes(URI uri) {
            try {
                return Files.toByteArray(new File(uri));
            } catch (IOException e) {
                throw Throwables.propagate(e);
            }
        }

        @Override
        String readString(URI uri, Charset charset) {
            try {
                return Files.toString(new File(uri), charset);
            } catch (IOException e) {
                throw Throwables.propagate(e);
            }
        }

        @Override
        String description(URI uri) {
            return new File(uri).getAbsolutePath();
        }
    }
}