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    • io.streamthoughts.azkarra.api.components.ComponentMetadata Maven / Gradle / Ivy

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    /*
 * Copyright 2019-2020 StreamThoughts.
 *
 * 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 io.streamthoughts.azkarra.api.components;

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.Objects;
import java.util.Optional;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class ComponentMetadata {

    private static final Function IDENTITY = object -> object;

    private final Collection attributes;

    /**
     * Creates a new {@link ComponentMetadata} instance.
     */
    public ComponentMetadata() {
        this(new LinkedList<>());
    }

    /**
     * Creates a new {@link ComponentMetadata} instance.
     *
     * @param attributes    the component attributes.
     */
    private ComponentMetadata(final Collection attributes) {
        this.attributes = attributes;
    }

    /**
     * Gets all attributes.
     *
     * @return      the list of {@link ComponentAttribute}.
     */
    public Collection attributes() {
        return Collections.unmodifiableCollection(attributes);
    }

    /**
     * Adds the specified attribute.
     *
     * @param attribute the attribute to add.
     */
    public void addAttribute(final ComponentAttribute attribute) {
        attributes.add(Objects.requireNonNull(attribute, "attribute cannot be null"));
    }

    /**
     * Gets all attributes for the given name.
     *
     * @param name  the name of attributes.
     * @return      the list of matching {@link ComponentAttribute}.
     */
    public Collection attributesForName(final String name) {
        return attributes.stream()
            .filter(attr -> attr.name().equalsIgnoreCase(name))
            .collect(Collectors.toList());
    }

    /**
     * Finds the value for the specified attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     * @return          the {@link Optional} value.
     */
    public Optional value(final String name, final String member) {
        return findValues(name, member, IDENTITY).findFirst();
    }

    /**
     * Finds all values for the specified attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     * @return          the {@link Optional} value.
     */
    public Collection values(final String name, final String member) {
        return findValues(name, member, IDENTITY).collect(Collectors.toList());
    }

    /**
     * Gets the string value for the specified attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     * @return          the string value if found, otherwise {@code null}.
     */
    public Collection stringValues(final String name, final String member) {
        return findValues(name, member, Object::toString).collect(Collectors.toList());
    }

    /**
     * Gets the string value for the specified attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     * @return          the string value if found, otherwise {@code null}.
     */
    public String stringValue(final String name, final String member) {
        return findValues(name, member, Object::toString).findFirst().orElse(null);
    }

    /**
     * Gets the array value for the specified attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     *
     * @return          the array value if found, otherwise {@code null}.
     */
    public String[] arrayValue(final String name, final String member) {
        return findValues(name, member, v -> (String[])v).findFirst().orElse(new String[0]);
    }

    /**
     * Checks whether the metadata contains the given value for the given attribute name and member.
     *
     * @param name      the name of the attribute.
     * @param member    the member of the attribute.
     * @param value     the member value.
     *
     * @return          {@code true} if the value exist, otherwise {@code false}.
     */
    public boolean contains(final String name, final String member, Object value) {
        Collection attributes = attributesForName(name);
        for (ComponentAttribute attribute : attributes) {
            if (attribute.contains(member, value)) {
                return true;
            }
        }
        return false;
    }

    private  Stream findValues(final String name, final String member, final Function mapper) {
        return attributesForName(name).stream()
            .map(attribute -> attribute.value(member))
            .filter(Objects::nonNull)
            .map(mapper);
    }
}
    
    
    
    

    




    
    
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