Objects.java

package de.invesdwin.util.lang;

import java.io.IOException;
import java.io.InputStream;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import javax.annotation.Nullable;
import javax.annotation.concurrent.Immutable;

import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.builder.CompareToBuilder;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;
import org.nustaq.serialization.FSTConfiguration;

import de.invesdwin.norva.apt.staticfacade.StaticFacadeDefinition;
import de.invesdwin.norva.beanpath.BeanPathObjects;
import de.invesdwin.norva.beanpath.IDeepCloneProvider;
import de.invesdwin.util.lang.internal.AObjectsStaticFacade;

@Immutable
@StaticFacadeDefinition(name = "de.invesdwin.util.lang.internal.AObjectsStaticFacade", targets = {
        BeanPathObjects.class })
public final class Objects extends AObjectsStaticFacade {

    public static final FSTConfiguration SERIALIZATION_CONFIG = FSTConfiguration.getDefaultConfiguration();
    public static final Set<String> REFLECTION_EXCLUDED_FIELDS = new HashSet<String>();

    static {
        //datanucleus enhancer fix
        REFLECTION_EXCLUDED_FIELDS.add("jdoDetachedState");
        REFLECTION_EXCLUDED_FIELDS.add("class");
        //use FST in BeanPathObjects as deepClone fallback instead of java serialization
        BeanPathObjects.setDeepCloneProvider(new IDeepCloneProvider() {
            @Override
            public <T> T deepClone(final T obj) {
                return Objects.deepClone(obj);
            }
        });
    }

    private Objects() {}

    public static <T> T defaultIfNull(final T object, final T defaultValue) {
        return org.apache.commons.lang3.ObjectUtils.defaultIfNull(object, defaultValue);
    }

    @SafeVarargs
    public static <T> T firstNonNull(final T... values) {
        return org.apache.commons.lang3.ObjectUtils.firstNonNull(values);
    }

    public static boolean equals(@Nullable final Object a, @Nullable final Object b) {
        return com.google.common.base.Objects.equal(a, b);
    }

    /**
     * Same as equals, just that an empty collection is equal to null.
     */
    public static boolean equalsProperty(final Object oldValue, final Object newValue) {
        if (!equals(oldValue, newValue)) {
            Iterable<?> iterable = null;
            Object other = null;
            if (oldValue instanceof Iterable) {
                iterable = (Iterable<?>) oldValue;
                other = newValue;
            } else if (newValue instanceof Iterable) {
                iterable = (Iterable<?>) newValue;
                other = oldValue;
            }
            if (iterable == null) {
                return false;
            } else {
                return !iterable.iterator().hasNext() && other == null;
            }
        } else {
            return true;
        }
    }

    public static int hashCode(final Object object) {
        return java.util.Objects.hashCode(object);
    }

    public static int hashCode(final Object o1, final Object o2) {
        //        final int prime = 31;
        //        int result = super.hashCode();
        //        result = prime * result + ((first == null) ? 0 : first.hashCode());
        //        result = prime * result + ((second == null) ? 0 : second.hashCode());
        //        return result;
        final int prime = 31;
        int result = 1;
        result = prime * result + hashCode(o1);
        result = prime * result + hashCode(o2);
        return result;
    }

    public static int hashCode(final Object o1, final Object o2, final Object o3) {
        final int prime = 31;
        int result = 1;
        result = prime * result + hashCode(o1);
        result = prime * result + hashCode(o2);
        result = prime * result + hashCode(o3);
        return result;
    }

    public static int hashCode(final Object o1, final Object o2, final Object o3, final Object o4) {
        final int prime = 31;
        int result = 1;
        result = prime * result + hashCode(o1);
        result = prime * result + hashCode(o2);
        result = prime * result + hashCode(o3);
        result = prime * result + hashCode(o4);
        return result;
    }

    public static int hashCode(final Object o1, final Object o2, final Object o3, final Object o4, final Object o5) {
        final int prime = 31;
        int result = 1;
        result = prime * result + hashCode(o1);
        result = prime * result + hashCode(o2);
        result = prime * result + hashCode(o3);
        result = prime * result + hashCode(o4);
        result = prime * result + hashCode(o5);
        return result;
    }

    public static int hashCode(final Object o1, final Object o2, final Object o3, final Object o4, final Object o5,
            final Object o6) {
        final int prime = 31;
        int result = 1;
        result = prime * result + hashCode(o1);
        result = prime * result + hashCode(o2);
        result = prime * result + hashCode(o3);
        result = prime * result + hashCode(o4);
        result = prime * result + hashCode(o5);
        result = prime * result + hashCode(o6);
        return result;
    }

    public static int hashCode(@Nullable final Object... objects) {
        return com.google.common.base.Objects.hashCode(objects);
    }

    @SuppressWarnings({ "unchecked", "null" })
    public static <T> T deepClone(final T obj) {
        if (obj == null) {
            return (T) null;
        }
        final byte[] serialized = serialize((Serializable) obj);
        return (T) deserialize(serialized);
    }

    @SuppressWarnings("unchecked")
    public static <T> T deserialize(final byte[] objectData) {
        return (T) SERIALIZATION_CONFIG.asObject(objectData);
    }

    public static <T> T deserialize(final InputStream in) {
        //FST is unreliable regarding input streams
        try {
            return deserialize(IOUtils.toByteArray(in));
        } catch (final IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static byte[] serialize(final Serializable obj) {
        return SERIALIZATION_CONFIG.asByteArray(obj);
    }

    public static String toString(final Object obj) {
        return Strings.asStringReflective(obj);
    }

    public static String toStringMultiline(final Object obj) {
        return Strings.asStringReflectiveMultiline(obj);
    }

    public static String toStringIdentity(final Object obj) {
        return Strings.asStringIdentity(obj);
    }

    public static ToStringHelper toStringHelper(final Object obj) {
        return new ToStringHelper(obj, false);
    }

    public static ToStringHelper toStringHelperMultiline(final Object obj) {
        return new ToStringHelper(obj, true);
    }

    public static int reflectionHashCode(final Object obj) {
        return hashCode(obj.getClass(), HashCodeBuilder.reflectionHashCode(obj, REFLECTION_EXCLUDED_FIELDS));
    }

    public static boolean reflectionEquals(final Object thisObj, final Object obj) {
        return EqualsBuilder.reflectionEquals(thisObj, obj, REFLECTION_EXCLUDED_FIELDS);
    }

    public static int reflectionCompareTo(final Object thisObj, final Object obj) {
        return CompareToBuilder.reflectionCompare(thisObj, obj, REFLECTION_EXCLUDED_FIELDS);
    }

}