commons-rdf-jena/src/main/java/org/apache/commons/rdf/jena/impl/JenaLiteralImpl.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.commons.rdf.jena.impl;

import java.util.Locale;
import java.util.Objects;
import java.util.Optional;

import org.apache.commons.rdf.api.IRI;
import org.apache.commons.rdf.api.Literal;
import org.apache.commons.rdf.jena.JenaLiteral;
import org.apache.jena.graph.Node;

class JenaLiteralImpl extends AbstractJenaRDFTerm implements JenaLiteral {

    private static final InternalJenaFactory INTERNAL_JENA_FACTORY = new InternalJenaFactory() {
    };

    JenaLiteralImpl(final Node node) {
        super(node);
        if (!node.isLiteral()) {
            throw new IllegalArgumentException("Node is not a literal: " + node);
        }
    }

    private static String lowerCase(final String langTag) {
        return langTag.toLowerCase(Locale.ROOT);
    }

    @Override
    public boolean equals(final Object other) {
        if (other == this) {
            return true;
        }
        if (other == null) {
            return false;
        }
        if (!(other instanceof Literal)) {
            return false;
        }
        final Literal literal = (Literal) other;
        return getLexicalForm().equals(literal.getLexicalForm()) &&
                getDatatype().equals(literal.getDatatype()) &&
                getLanguageTag().map(JenaLiteralImpl::lowerCase).equals(
                        literal.getLanguageTag().map(JenaLiteralImpl::lowerCase));
    }

    @Override
    public IRI getDatatype() {
        return INTERNAL_JENA_FACTORY.createIRI(asJenaNode().getLiteralDatatype().getURI());
    }

    @Override
    public Optional<String> getLanguageTag() {
        final String x = asJenaNode().getLiteralLanguage();
        if (x == null || x.isEmpty()) {
            return Optional.empty();
        }
        return Optional.of(x);
    }

    @Override
    public String getLexicalForm() {
        return asJenaNode().getLiteralLexicalForm();
    }

    @Override
    public int hashCode() {
        return Objects.hash(getLexicalForm(), getDatatype(), getLanguageTag().map(JenaLiteralImpl::lowerCase));
    }
}