JavaPackage.java

package org.springframework.roo.model;

import java.util.Arrays;
import java.util.List;

import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;

/**
 * Immutable representation of a Java package.
 * <p>
 * This class is used whenever a formal reference to a Java package is required.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public class JavaPackage implements Comparable<JavaPackage> {

  private final String fullyQualifiedPackageName;
  private String module;

  /**
   * Construct a JavaPackage.
   * <p>
   * The fully qualified package name will be enforced as follows:
   * <ul>
   * <li>The rules listed in
   * {@link JavaSymbolName#assertJavaNameLegal(String)}
   * </ul>
   * 
   * @param fullyQualifiedPackageName the name (as per the above rules;
   *            mandatory)
   */
  public JavaPackage(final String fullyQualifiedPackageName) {
    Validate.notNull(fullyQualifiedPackageName, "Fully qualified package name required");
    JavaSymbolName.assertJavaNameLegal(fullyQualifiedPackageName);
    this.fullyQualifiedPackageName = fullyQualifiedPackageName;
  }

  /**
   * Construct a JavaPackage.
   * <p>
   * The fully qualified package name will be enforced as follows:
   * <ul>
   * <li>The rules listed in
   * {@link JavaSymbolName#assertJavaNameLegal(String)}
   * </ul>
   * 
   * @param fullyQualifiedPackageName the name (as per the above rules;
   *            mandatory)
   * @param module the module where is created (optional)
   */
  public JavaPackage(final String fullyQualifiedPackageName, final String module) {
    this(fullyQualifiedPackageName);
    this.module = module;
  }

  public int compareTo(final JavaPackage o) {
    if (o == null) {
      return -1;
    }
    return fullyQualifiedPackageName.compareTo(o.getFullyQualifiedPackageName());
  }

  @Override
  public boolean equals(final Object obj) {
    return obj instanceof JavaPackage && compareTo((JavaPackage) obj) == 0;
  }

  /**
   * Returns the elements of this package's fully-qualified name
   * 
   * @return a non-empty list
   */
  public List<String> getElements() {
    return Arrays.asList(StringUtils.split(fullyQualifiedPackageName, "."));
  }

  /**
   * @return the fully qualified package name (complies with the rules
   *         specified in the constructor)
   */
  public String getFullyQualifiedPackageName() {
    return fullyQualifiedPackageName;
  }

  /**
    * @return the module name where the javaPackage is located 
    */
  public String getModule() {
    return module;
  }

  /**
   * Returns the last element of the fully-qualified package name
   * 
   * @return a non-blank element
   */
  public String getLastElement() {
    final List<String> elements = getElements();
    return elements.get(elements.size() - 1);
  }

  @Override
  public int hashCode() {
    return fullyQualifiedPackageName.hashCode();
  }

  /**
   * Indicates whether this package is anywhere within the given package, in
   * other words is the same package or is a sub-package of the given one. For
   * example:
   * <ul>
   * <li>com.foo is within com.foo</li>
   * <li>com.foo.bar is within com.foo</li>
   * <li>com.foo is not within com.foo.bar</li>
   * </ul>
   * 
   * @param otherPackage the package to check against (can be
   *            <code>null</code>)
   * @return <code>false</code> if a <code>null</code> package is given
   */
  public boolean isWithin(final JavaPackage otherPackage) {
    return otherPackage != null
        && fullyQualifiedPackageName.startsWith(otherPackage.getFullyQualifiedPackageName());
  }

  @Override
  public String toString() {
    return fullyQualifiedPackageName;
  }
}