Initial checkin

src/main/java/com/softwarecraftsmen/dns/labels/SimpleLabel.java

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+/**
+ * This file is Copyright © 2008 Software Craftsmen Limited. All Rights Reserved.
+ */
+package com.softwarecraftsmen.dns.labels;
+
+import static com.softwarecraftsmen.dns.NonAsciiAndControlCharactersAreNotSupportedInCharacterStringsException.throwExceptionIfUnsupportedCharacterCode;
+import com.softwarecraftsmen.dns.messaging.serializer.AtomicWriter;
+import static com.softwarecraftsmen.dns.labels.ServiceLabel.serviceLabel;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import static java.lang.String.format;
+import java.util.ArrayList;
+import java.util.List;
+import static java.util.Locale.UK;
+
+public class SimpleLabel implements Label, Comparable<SimpleLabel>
+{
+	@NotNull
+	public static final SimpleLabel Empty = new SimpleLabel("");
+
+	private final String value;
+
+	private SimpleLabel(final @NotNull String value)
+	{
+		if (value.length() > 63)
+		{
+			throw new LabelsCanNotBeLongerThan63CharactersException(value);
+		}
+		for (char toWrite : value.toCharArray())
+		{
+			throwExceptionIfUnsupportedCharacterCode(toWrite);
+			if (toWrite == '.')
+			{
+				throw new LabelsCanNotContainPeriodsException(value);
+			}
+		}
+		this.value = value;
+	}
+
+	@NotNull
+	public static SimpleLabel simpleLabel(final @NotNull String value)
+	{
+		if (value.length() == 0)
+		{
+			return Empty;
+		}
+		return new SimpleLabel(value);
+	}
+
+	public boolean equals(final @Nullable Object o)
+	{
+		if (this == o)
+		{
+			return true;
+		}
+		if (o == null || getClass() != o.getClass())
+		{
+			return false;
+		}
+
+		final SimpleLabel that = (SimpleLabel) o;
+		return value.equals(that.value);
+	}
+
+	public int hashCode()
+	{
+		return value.hashCode();
+	}
+
+	@NotNull
+	public String toString()
+	{
+		return value;
+	}
+
+	@NotNull
+	public String toStringRepresentation()
+	{
+		return value;
+	}
+
+	@NotNull
+	public static List<SimpleLabel> labelsFromDottedName(final String dottedName)
+	{
+		final String[] values = dottedName.split("\\.");
+		return new ArrayList<SimpleLabel>()
+		{{
+			for (String value : values)
+			{
+				add(simpleLabel(value));
+			}
+		}};
+	}
+
+	public boolean isEmpty()
+	{
+		return value.length() == 0;
+	}
+
+	public int length()
+	{
+		return value.length();
+	}
+
+	public void serialize(final @NotNull AtomicWriter writer)
+	{
+		writer.writeCharacterString(value);
+	}
+
+	@NotNull
+	public ServiceLabel toServiceLabel()
+	{
+		return serviceLabel(value);
+	}
+
+	@NotNull
+	public ServiceProtocolLabel toServiceProtocolLabel()
+	{
+		try
+		{
+			return ServiceProtocolLabel.toServiceProtocolLabel(value);
+		}
+		catch(IllegalArgumentException e)
+		{
+			throw new IllegalStateException(e);
+		}
+	}
+
+	public int compareTo(final @NotNull SimpleLabel that)
+	{
+		return this.value.compareTo(that.value);
+	}
+
+	public final class LabelsCanNotContainPeriodsException extends IllegalArgumentException
+	{
+		public LabelsCanNotContainPeriodsException(final @NotNull String value)
+		{
+			super(format(UK, "Labels (the strings between dots in a DNS name) can not contain the period character. This label, %1$s, does.", value));
+		}
+
+		public void throwExceptionIfCharacterIsAPeriod(final char toWrite)
+		{
+			if (toWrite == '.')
+			{
+				throw new LabelsCanNotContainPeriodsException(value);
+			}
+		}
+	}
+
+	public static final class LabelsCanNotBeLongerThan63CharactersException extends IllegalArgumentException
+	{
+		public LabelsCanNotBeLongerThan63CharactersException(final @NotNull String label)
+		{
+			super(format(UK, "Labels (the strings between dots in a DNS name) can not be longer than 63 character. This label, %1$s, is.", label));
+		}
+	}
+}