org.scijava.util.StringMaker Maven / Gradle / Ivy

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package org.scijava.util;

import java.util.Collection;
import java.util.Iterator;

/**
 * Helper class for building up {@link String}s of key/value pairs.
 * 
 * @author Curtis Rueden
 */
public final class StringMaker {

	private final StringBuilder builder;

	public StringMaker() {
		builder = new StringBuilder();
	}

	public StringMaker(final String s) {
		builder = new StringBuilder(s);
	}

	// -- Object methods --

	@Override
	public String toString() {
		return builder.toString();
	}

	// -- StringMaker methods --

	public void append(final String s) {
		if (builder.length() > 0) builder.append(", ");
		builder.append(s);
	}

	public void append(final String key, final Object value) {
		append(key, value, null);
	}

	public void append(final String key, final Object value,
		final Object defaultValue)
	{
		if (value == null || value.equals(defaultValue)) return;

		final String s = makeString(value);
		if (s == null) return;

		if (builder.length() > 0) builder.append(", ");
		builder.append(key + "=" + s);
	}

	// -- Helper methods --

	private String makeString(final Object value) {
		if (value == null) return null;
		if (value instanceof String) {
			final String s = (String) value;
			if (s.isEmpty()) return null;
			return "'" + s + "'";
		}
		if (value instanceof Class) {
			final Class c = (Class) value;
			return c.getSimpleName();
		}
		if (value instanceof Collection) {
			final Collection c = (Collection) value;
			if (c.isEmpty()) return null;
			final StringBuilder sb = new StringBuilder();
			final Iterator iter = c.iterator();
			while (iter.hasNext()) {
				if (sb.length() > 0) sb.append(", ");
				final Object o = iter.next();
				sb.append(makeString(o));
			}
			return "{" + sb.toString() + "}";
		}
		return value.toString();
	}

}