de.agilecoders.wicket.markup.html.bootstrap.behavior.CssClassNameAppender Maven / Gradle / Ivy

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package de.agilecoders.wicket.markup.html.bootstrap.behavior;

import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.Lists;
import org.apache.wicket.behavior.AttributeAppender;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;
import org.apache.wicket.util.string.Strings;

import java.util.List;

/**
 * A CssClassNameAppender appends the given value, rather than replace it. This is especially useful
 * for adding CSS classes to markup elements.
 * 
 * 
 *     <span class="className" wicket:id="foo">
 * 
 * 
 * can be modified with these CssClassNameAppender:
 * 

 * 
 * link.add(new CssClassNameAppender("className2"));
 * link.add(new CssClassNameAppender(Arrays.asList("className2","className3")));
 * 
 * 
 * this will result in the following markup:
 * 

 * 
 *     <span class="className className2 className3" wicket:id="foo" >
 * 
 *
 * @author miha
 * @version 1.0
 */
public class CssClassNameAppender extends AttributeAppender {

    /**
     * Separator between the current value and the concatenated value.
     */
    protected static final String SEPARATOR = " ";

    /**
     * The name of the html class attribute name.
     */
    protected static final String ATTRIBUTE_NAME = "class";

    /**
     * @return separator between the current value and the concatenated value.
     */
    public static String separator() {
        return SEPARATOR;
    }

    /**
     * Creates an AttributeModifier that appends the appendModel's value to the current value of the
     * class attribute, and will add the attribute when it is not there already.
     *
     * @param appendModel the model supplying a single value to append
     */
    public CssClassNameAppender(IModel appendModel) {
        super(ATTRIBUTE_NAME, appendModel, SEPARATOR);
    }

    /**
     * Constructor.
     * {@link CssClassNameAppender#CssClassNameAppender(org.apache.wicket.model.IModel)}
     *
     * @param appendValue one or more values to append
     */
    public CssClassNameAppender(String... appendValue) {
        this(Lists.newArrayList(appendValue));
    }

    /**
     * Constructor.
     * {@link CssClassNameAppender#CssClassNameAppender(org.apache.wicket.model.IModel)}
     *
     * @param appendValueList a list of values to append
     */
    public CssClassNameAppender(List appendValueList) {
        this(Model.of(Joiner.on(SEPARATOR).skipNulls().join(appendValueList)));
    }

    /**
     * Constructor.
     * {@link CssClassNameAppender#CssClassNameAppender(org.apache.wicket.model.IModel)}
     *
     * @param cssClassNameProvider a css class name provider
     */
    public CssClassNameAppender(CssClassNameProvider cssClassNameProvider) {
        this(Model.of(cssClassNameProvider.cssClassName()));
    }

    @Override
    protected String newValue(String currentValue, String appendValue) {
        // Short circuit when one of the values is empty: return the other value.
        if (Strings.isEmpty(currentValue)) {
            return appendValue != null ? appendValue : null;
        } else if (Strings.isEmpty(appendValue)) {
            return currentValue != null ? currentValue : null;
        }

        List values = Lists.newArrayList(Splitter.on(separator()).trimResults().split(currentValue));
        List appendValues = Lists.newArrayList(Splitter.on(separator()).trimResults().split(appendValue));

        StringBuilder sb = new StringBuilder(currentValue);

        for (String append : appendValues) {
            if (!values.contains(append) && append != null && !"".equals(append)) {
                sb.append(separator());
                sb.append(append);
            }
        }

        return sb.toString().trim();
    }
}