com.autentia.wuija.i18n.SequenceResource.java Source code

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Here is the source code for com.autentia.wuija.i18n.SequenceResource.java

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/**
 * Copyright 2008 Autentia Real Business Solutions S.L.
 *
 * This file is part of Autentia WUIJA.
 *
 * Autentia WUIJA 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, version 3 of the License.
 *
 * Autentia WUIJA 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 Autentia WUIJA. If not, see <http://www.gnu.org/licenses/>.
 */
package com.autentia.wuija.i18n;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.net.URI;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.springframework.core.io.Resource;
import org.springframework.util.Assert;

/**
 * Esta clase permite ver un conjunto de <code>Resource</code> como si se tratara de uno solo. La idea es que la ir
 * leyendo el <code>InputStream</code> de esta clase, iremos leyendo del <code>InputStream</code> del primer
 * <code>Resource</code>, cuando este se acabe, leeremos del segundo, luego del tercero, ...
 */
public class SequenceResource implements Resource {

    private final Resource[] resources;

    public SequenceResource(Resource[] resources) {
        Assert.notEmpty(resources, "Array of resources cannot be null or empty");
        this.resources = resources;
    }

    public Resource createRelative(String relativePath) throws IOException {
        throw new IOException();
    }

    public boolean exists() {
        return resources[0].exists();
    }

    public String getDescription() {
        return resources[0].getDescription();
    }

    public File getFile() throws IOException {
        return resources[0].getFile();
    }

    public String getFilename() {
        return resources[0].getFilename();
    }

    public URI getURI() throws IOException {
        return resources[0].getURI();
    }

    public URL getURL() throws IOException {
        return resources[0].getURL();
    }

    public boolean isOpen() {
        return resources[0].isOpen();
    }

    public boolean isReadable() {
        return resources[0].isReadable();
    }

    public long lastModified() throws IOException {
        return resources[0].lastModified();
    }

    /**
     * Devuelve un nico <code>InputStream</code> que es el resultado de concatenar todos los <code>InputStream</code>
     * de los <code>Resource</code> que se pasaron en el constructor.
     * <p>
     * Para conseguir esto, esta clase utiliza la clase <code>java.io.SequenceInputStream</code> de Java.
     * 
     * @return un nico <code>InputStream</code> que es el resultado de concatenar todos los <code>InputStream</code> de
     *         los <code>Resource</code> que se pasaron en el constructor.
     */
    public InputStream getInputStream() throws IOException {
        final List<InputStream> ins = new ArrayList<InputStream>(resources.length);
        for (Resource resource : resources) {
            ins.add(resource.getInputStream());
        }
        final Enumeration<InputStream> streamsEnumeration = Collections.enumeration(ins);
        return new SequenceInputStream(streamsEnumeration);
    }

}