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Issue #1797 Multi Release Jar javadoc

This commit is contained in:
Greg Wilkins 2017-09-20 15:40:17 +10:00
parent 5de895af88
commit 6b7bbbe66a
1 changed files with 166 additions and 25 deletions
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191
jetty-util/src/main/java/org/eclipse/jetty/util/MultiReleaseJarFile.java
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@ -20,44 +20,132 @@ package org.eclipse.jetty.util;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.stream.Stream;
/**
* <p>Utility class to create a stream of Multi Release {@link JarEntry}s</p>
* <p>This is the java 8 version of this class.
* A java 9 version of this class is included as a Multi Release class in the
* jetty-util jar, that uses java 9 APIs to correctly handle Multi Release jars.</p>
* <p>Utility class to handle a Multi Release Jar file</p>
*/
public class MultiReleaseJarFile
{
private static final String META_INF_VERSIONS = "META-INF/versions/";
public static JarFile open(File file) throws IOException
private final JarFile jarFile;
private final int majorVersion;
private final boolean multiRelease;
/* Map to hold unversioned name to VersionedJarEntry */
private final Map<String,VersionedJarEntry> entries;
/**
* Construct a multi release jar file for the current JVM version, ignoring directories.
* @param file The file to open
*/
public MultiReleaseJarFile(File file) throws IOException
{
return new JarFile(file);
this(file,JavaVersion.VERSION.getMajor(),false);
}
public static Stream<VersionedJarEntry> streamVersioned(JarFile jf)
/**
* Construct a multi release jar file
* @param file The file to open
* @param majorVersion The major JVM version to apply when selecting a version.
* @param includeDirectories true if any directory entries should not be ignored
* @throws IOException if the jar file cannot be read
*/
public MultiReleaseJarFile(File file, int majorVersion, boolean includeDirectories) throws IOException
{
return jf.stream()
.map(VersionedJarEntry::new);
if (file==null || !file.exists() || !file.canRead() || file.isDirectory())
throw new IllegalArgumentException("bad jar file: "+file);
jarFile = new JarFile(file,true,JarFile.OPEN_READ);
this.majorVersion = majorVersion;
Manifest manifest = jarFile.getManifest();
if (manifest==null)
multiRelease = false;
else
multiRelease = Boolean.valueOf(String.valueOf(manifest.getMainAttributes().getValue("Multi-Release")));
Map<String,VersionedJarEntry> map = new TreeMap<>();
jarFile.stream()
.map(VersionedJarEntry::new)
.filter(e->(includeDirectories||!e.isDirectory()) && e.isApplicable())
.forEach(e->map.compute(e.name, (k, v) -> v==null || v.isReplacedBy(e) ? e : v));
for (Iterator<Map.Entry<String,VersionedJarEntry>> i = map.entrySet().iterator();i.hasNext();)
{
Map.Entry<String,VersionedJarEntry> e = i.next();
VersionedJarEntry entry = e.getValue();
if (entry.inner)
{
VersionedJarEntry outer = map.get(entry.outer);
if (entry.outer==null || outer.version!= entry.version)
i.remove();
}
}
entries = Collections.unmodifiableMap(map);
}
public static Stream<JarEntry> stream(JarFile jf)
/**
* @return true IFF the jar is a multi release jar
*/
public boolean isMultiRelease()
{
// Java 8 version of this class, ignores all versioned entries.
return streamVersioned(jf)
.filter(e->!e.isVersioned())
.map(e->e.resolve(jf));
return multiRelease;
}
public static class VersionedJarEntry
/**
* @return The major version applied to this jar for the purposes of selecting entries
*/
public int getVersion()
{
return majorVersion;
}
/**
* @return A stream of versioned entries from the jar, excluded any that are not applicable
*/
public Stream<VersionedJarEntry> stream()
{
return entries.values().stream();
}
/** Get a versioned resource entry by name
* @param name The unversioned name of the resource
* @return The versioned entry of the resource
*/
public VersionedJarEntry getEntry(String name)
{
return entries.get(name);
}
@Override
public String toString()
{
return String.format("%s[%b,%d]",jarFile.getName(),isMultiRelease(),getVersion());
}
/**
* A versioned Jar entry
*/
public class VersionedJarEntry
{
final JarEntry entry;
final String name;
final int version;
final boolean inner;
final String outer;
VersionedJarEntry(JarEntry entry)
{
@ -65,17 +153,18 @@ public class MultiReleaseJarFile
String name = entry.getName();
if (name.startsWith(META_INF_VERSIONS))
{
v=-1;
v = -1;
int index = name.indexOf('/', META_INF_VERSIONS.length());
if (index >= 0 && index < name.length())
if (index > META_INF_VERSIONS.length() && index < name.length())
{
try
{
v = Integer.parseInt(name.substring(META_INF_VERSIONS.length(), index), 10);
v = TypeUtil.parseInt(name, META_INF_VERSIONS.length(), index - META_INF_VERSIONS.length(), 10);
name = name.substring(index + 1);
}
catch (NumberFormatException x)
{
throw new RuntimeException("illegal version in "+jarFile,x);
}
}
}
@ -83,27 +172,79 @@ public class MultiReleaseJarFile
this.entry = entry;
this.name = name;
this.version = v;
this.inner = name.contains("$") && name.toLowerCase().endsWith(".class");
this.outer = inner ? name.substring(0, name.indexOf('$')) + name.substring(name.length() - 6, name.length()) : null;
}
public int version()
/**
* @return the unversioned name of the resource
*/
public String getName()
{
return name;
}
/**
* @return The name of the resource within the jar, which could be versioned
*/
public String getNameInJar()
{
return entry.getName();
}
/**
* @return The version of the resource or 0 for a base version
*/
public int getVersion()
{
return version;
}
/**
*
* @return True iff the entry is not from the base version
*/
public boolean isVersioned()
{
return version > 0;
}
/**
*
* @return True iff the entry is a directory
*/
public boolean isDirectory()
{
return entry.isDirectory();
}
/**
* @return An input stream of the content of the versioned entry.
* @throws IOException if something goes wrong!
*/
public InputStream getInputStream() throws IOException
{
return jarFile.getInputStream(entry);
}
boolean isApplicable()
{
if (multiRelease)
return this.version>=0 && this.version <= majorVersion && name.length()>0;
return this.version==0;
}
boolean isReplacedBy(VersionedJarEntry entry)
{
if (isDirectory())
return entry.version==0;
return this.name.equals(entry.name) && entry.version>version;
}
@Override
public String toString()
{
return entry.toString() + (version==0?"[base]":("["+version+"]"));
}
public JarEntry resolve(JarFile jf)
{
return entry;
return String.format("%s->%s[%d]",name,entry.getName(),version);
}
}
}