JarEntry.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package java.util.jar;

import java.io.IOException;
import java.util.zip.ZipEntry;
import java.security.CodeSigner;
import java.security.cert.Certificate;

/**
 * This class is used to represent a JAR file entry.
 *
 * @since 1.2
 */
// jar包中的实体条目
public class JarEntry extends ZipEntry {
    
    Attributes attr;        // jar实体中"META-INF/MANIFEST.MF"文件的键值对数据
    CodeSigner[] signers;
    Certificate[] certs;
    
    
    /**
     * Creates a new <code>JarEntry</code> for the specified JAR file
     * entry name.
     *
     * @param name the JAR file entry name
     *
     * @throws NullPointerException     if the entry name is <code>null</code>
     * @throws IllegalArgumentException if the entry name is longer than
     *                                  0xFFFF bytes.
     */
    public JarEntry(String name) {
        super(name);
    }
    
    /**
     * Creates a new <code>JarEntry</code> with fields taken from the
     * specified <code>ZipEntry</code> object.
     *
     * @param ze the <code>ZipEntry</code> object to create the
     *           <code>JarEntry</code> from
     */
    public JarEntry(ZipEntry ze) {
        super(ze);
    }
    
    /**
     * Creates a new <code>JarEntry</code> with fields taken from the
     * specified <code>JarEntry</code> object.
     *
     * @param je the <code>JarEntry</code> to copy
     */
    public JarEntry(JarEntry je) {
        this((ZipEntry) je);
        this.attr = je.attr;
        this.certs = je.certs;
        this.signers = je.signers;
    }
    
    /**
     * Returns the real name of this {@code JarEntry}.
     *
     * If this {@code JarEntry} is an entry of a
     * <a href="JarFile.html#multirelease">multi-release jar file</a> and the
     * {@code JarFile} is configured to be processed as such, the name returned
     * by this method is the path name of the versioned entry that the
     * {@code JarEntry} represents, rather than the path name of the base entry
     * that {@link #getName()} returns. If the {@code JarEntry} does not represent
     * a versioned entry of a multi-release {@code JarFile} or the {@code JarFile}
     * is not configured for processing a multi-release jar file, this method
     * returns the same name that {@link #getName()} returns.
     *
     * @return the real name of the JarEntry
     *
     * @since 10
     */
    // 返回当前jar实体的名称
    public String getRealName() {
        return super.getName();
    }
    
    /**
     * Returns the <code>Manifest</code> <code>Attributes</code> for this
     * entry, or <code>null</code> if none.
     *
     * @return the <code>Manifest</code> <code>Attributes</code> for this
     * entry, or <code>null</code> if none
     *
     * @throws IOException if an I/O error has occurred
     */
    // 返回jar实体中"META-INF/MANIFEST.MF"文件的键值对数据
    public Attributes getAttributes() throws IOException {
        return attr;
    }
    
    /**
     * Returns the <code>CodeSigner</code> objects for this entry, or
     * <code>null</code> if none. This method can only be called once
     * the <code>JarEntry</code> has been completely verified by reading
     * from the entry input stream until the end of the stream has been
     * reached. Otherwise, this method will return <code>null</code>.
     *
     * <p>The returned array comprises all the code signers that have signed
     * this entry.
     *
     * @return the <code>CodeSigner</code> objects for this entry, or
     * <code>null</code> if none.
     *
     * @since 1.5
     */
    public CodeSigner[] getCodeSigners() {
        return signers == null ? null : signers.clone();
    }
    
    /**
     * Returns the <code>Certificate</code> objects for this entry, or
     * <code>null</code> if none. This method can only be called once
     * the <code>JarEntry</code> has been completely verified by reading
     * from the entry input stream until the end of the stream has been
     * reached. Otherwise, this method will return <code>null</code>.
     *
     * <p>The returned certificate array comprises all the signer certificates
     * that were used to verify this entry. Each signer certificate is
     * followed by its supporting certificate chain (which may be empty).
     * Each signer certificate and its supporting certificate chain are ordered
     * bottom-to-top (i.e., with the signer certificate first and the (root)
     * certificate authority last).
     *
     * @return the <code>Certificate</code> objects for this entry, or
     * <code>null</code> if none.
     */
    public Certificate[] getCertificates() {
        return certs == null ? null : certs.clone();
    }
    
}