org.owasp.shim.Java8Shim Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of java8-shim Show documentation

Backports @since Java 9 collection factories like List.of onto Java8 in a way that uses the real ones where available, falls back to a conforming implementation on Java8 and JIT compiles well.

The newest version!

package org.owasp.shim;

import java.util.*;

/**
 * Static adapters for Java 9 APIs that we need to support on Java 8.
 */
@SuppressWarnings("JavadocReference")
public abstract class Java8Shim {
    /** Statically import this and do `j8.listOf(...)`. */
    public static Java8Shim j8() { return instance; }

    Java8Shim() {} // Not public so there can only be one instance loaded below.

    private static final Java8Shim instance;
    static {
        Object _instance;
        try {
            try {
                // This is compiled with -release 1.9 in a separate project.
                _instance = Class.forName("org.owasp.shim.ForJava9AndLater").newInstance();
            } catch (Error e) {
                // This is co-located with this project and is a fall-back.
                _instance = Class.forName("org.owasp.shim.ForJava8").newInstance();
            }
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
            throw new Error(e);
        }
        instance = (Java8Shim) _instance;
    }

    /**
     * {@link java.util.List.of}
     */
    public abstract  List listOf();

    /**
     * {@link java.util.List.of}
     */
    public abstract  List listOf(T a);

    /**
     * {@link java.util.List.of}
     */
    public abstract  List listOf(T a, T b);

    /**
     * {@link java.util.List.of}
     */
    public abstract  List listOf(T a, T b, T c);

    /**
     * {@link java.util.List.of}
     */
    public abstract  List listOf(T... els);

    /**
     * {@link java.util.List.copyOf}
     */
    public abstract  List listCopyOf(Collection c);

    /**
     * {@link java.util.Map.copyOf}
     */
    public abstract  Map mapCopyOf(Map m);

    /**
     * {@link java.util.Map.entry}
     */
    public abstract  Map.Entry mapEntry(K key, V value);

    /**
     * {@link java.util.Map.ofEntries}
     */
    public abstract  Map mapOfEntries(Map.Entry... entries);

    /**
     * {@link java.util.Set.of}
     */
    public abstract  Set setOf();

    /**
     * {@link java.util.Set.of}
     */
    public abstract  Set setOf(T a);

    /**
     * {@link java.util.Set.of}
     */
    public abstract  Set setOf(T a, T b);

    /**
     * {@link java.util.Set.of}
     */
    public abstract  Set setOf(T a, T b, T c);

    /**
     * {@link java.util.Set.of}
     */
    public abstract  Set setOf(T... els);

    /**
     * {@link java.util.Set.copyOf}
     */
    public abstract  Set setCopyOf(Collection c);
}