org.daisy.dotify.api.writer.MetaDataItem Maven / Gradle / Ivy

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package org.daisy.dotify.api.writer;

import javax.xml.namespace.QName;

/**
 * Provides a simple meta data item. A meta data item can contain an element name,
 * text content and an attribute key/value. Thereby, this model supports the two
 * most common types of meta data elements in XML-formats while remaining reasonably
 * well-defined:
 * 
 * Specific element with content, for example:
 *  * <dc:title>Example</dc:title>
 * 
 * 
 * Generic element + specific attribute key and value, for example:
 *  * <meta name="dc:title" value="Example"/>
 * 
 * 
 * 
 *
 * @author Joel Håkansson
 */
public class MetaDataItem {

    private final QName key;
    private final String value;
    private final AttributeItem attribute;


    /**
     * Provides a meta data item builder.
     */
    public static class Builder {
        private final QName elementKey;
        private final String elementValue;
        private AttributeItem attribute;

        /**
         * Creates a new meta data item builder.
         *
         * @param elementKey   the element name
         * @param elementValue the element value, (in other words, its text contents)
         */
        public Builder(QName elementKey, String elementValue) {
            this.elementKey = elementKey;
            this.elementValue = elementValue;
        }

        /**
         * Sets the item's attribute.
         *
         * @param value the attribute
         * @return returns this builder
         */
        public Builder attribute(AttributeItem value) {
            this.attribute = value;
            return this;
        }

        /**
         * Creates a new meta data item based on the current
         * state of the builder.
         *
         * @return returns a new meta data item
         */
        public MetaDataItem build() {
            return new MetaDataItem(this);
        }
    }

    /**
     * Creates a new meta data item with the specified parameters.
     *
     * @param key   the element name
     * @param value the text contents of the element
     */
    public MetaDataItem(QName key, String value) {
        this.key = key;
        this.value = value;
        this.attribute = null;
    }

    private MetaDataItem(Builder builder) {
        this.key = builder.elementKey;
        this.value = builder.elementValue;
        this.attribute = builder.attribute;
    }

    /**
     * Gets the element name.
     *
     * @return returns the name of the meta data item
     */
    public QName getKey() {
        return key;
    }

    /**
     * Gets the text contents of this meta data item.
     *
     * @return returns the text contents
     */
    public String getValue() {
        return value;
    }

    /**
     * Gets the attribute, if specified or null.
     *
     * @return the attribute
     */
    public AttributeItem getAttribute() {
        return attribute;
    }

}