gcc/libjava/classpath/javax/management/openmbean/CompositeData.java

/* CompositeData.java -- A composite data structure.
   Copyright (C) 2006, 2007 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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GNU Classpath is distributed in the hope that it will be useful, but
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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package javax.management.openmbean;

import java.util.Collection;

/**
 * Provides an interface to a composite data structure,
 * in order to aid interoperability.  The composite data
 * structure is represented by mapping field names to
 * values.
 *
 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
 * @since 1.5
 */
public interface CompositeData
{

  /**
   * Returns true if this {@link CompositeData} instance contains
   * the specified key.  This method always returns false for
   * an input key equal to <code>null</code> or the empty string.
   *
   * @param key the key to find in the structure.
   * @return true if the key exists.
   */
  boolean containsKey(String key);

  /**
   * Returns true if this {@link CompositeData} instance has
   * a value equal to that supplied.
   *
   * @param value the value to look for.
   * @return true if the value exists.
   */
  boolean containsValue(Object value);

  /**
   * Compares the specified object with this object for equality.
   * The object is judged equivalent if it is non-null, and also
   * an instance of {@link CompositeData} with the same name-value
   * mappings and types.  The two compared instances may be
   * equivalent even if they represent different implementations of
   * {@link CompositeData}.
   *
   * @param obj the object to compare for equality.
   * @return true if <code>obj</code> is equal to <code>this</code>.
   */
  boolean equals(Object obj);

  /**
   * Retrieves the value for the specified key.
   *
   * @param key the key whose value should be returned.
   * @return the matching value.
   * @throws IllegalArgumentException if the key is <code>null</code>
   *                                  or the empty string.
   * @throws InvalidKeyException if the key does not exist.
   */
  Object get(String key);

  /**
   * Returns the appropriate value for each key in the given array,
   * using the same ordering.
   *
   * @param keys the keys whose values should be returned.
   * @return the matching values.
   * @throws IllegalArgumentException if one of the keys is
   *                                  <code>null</code> or the
   *                                  empty string.
   * @throws InvalidKeyException if one of the keys does not exist.
   */
  Object[] getAll(String[] keys);

  /**
   * Returns the composite type which corresponds to this instance
   * of {@link CompositeData}.
   *
   * @return the composite type for this instance.
   */
  CompositeType getCompositeType();

  /**
   * Returns the hash code of this instance.  The hash code is
   * computed as the sum of the hash codes of all the values plus
   * the hash code of the composite type.  As equality comparisons
   * take place using this same information, this ensures that
   * the property, <code>e1.equals(e2)</code> implies
   * <code>e1.hashCode() == e2.hashCode(), holds for any pair
   * of instances, <code>e1</code> and <code>e2</code>.
   *
   * @return the hash code of this {@link CompositeData}.
   * @see Object#equals(Object)
   */
  int hashCode();

  /**
   * Returns a textual representation of this instance.  The
   * exact format is left up to the implementation, but it
   * should contain the name of the implementing class,
   * the name of the type and a mapping of the form
   * <code>key=value</code> for each pair of key and value.
   *
   * @return a {@link java.lang.String} representation of the
   *         object.
   */
  String toString();

  /**
   * Returns a read-only collection of the values associated with
   * this instance.  The values are sorted using the lexicographic
   * ordering of the corresponding keys.
   *
   * @return the values of this instance.
   */
  Collection<?> values();

}