src/java.management/share/classes/javax/management/openmbean/CompositeData.java

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package javax.management.openmbean;


// java import
//
import java.util.Collection;

// jmx import
//


/**
 * The {@code CompositeData} interface specifies
 * the behavior of a specific type of complex <i>open data</i> objects
 * which represent <i>composite data</i> structures.
 *
 *
 * @since 1.5
 */
public interface CompositeData {


    /**
     * Returns the <i>composite type </i> of this <i>composite data</i> instance.
     *
     * @return the type of this CompositeData.
     */
    public CompositeType getCompositeType();

    /**
     * Returns the value of the item whose name is {@code key}.
     *
     * @param key the name of the item.
     *
     * @return the value associated with this key.
     *
     * @throws IllegalArgumentException  if {@code key} is a null or empty String.
     *
     * @throws InvalidKeyException  if {@code key} is not an
     *         existing item name for this {@code CompositeData} instance.
     */
    public Object get(String key) ;

    /**
     * Returns an array of the values of the items whose names
     * are specified by {@code keys}, in the same order as {@code keys}.
     *
     * @param keys the names of the items.
     *
     * @return the values corresponding to the keys.
     *
     * @throws IllegalArgumentException  if an element in {@code keys} is a null or empty String.
     *
     * @throws InvalidKeyException  if an element in {@code keys}
     *         is not an existing item name for this {@code CompositeData} instance.
     */
    public Object[] getAll(String[] keys) ;

    /**
     * Returns {@code true} if and only if this {@code CompositeData} instance contains
     * an item whose name is {@code key}.
     * If {@code key} is a null or empty String, this method simply returns false.
     *
     * @param key the key to be tested.
     *
     * @return true if this {@code CompositeData} contains the key.
     */
    public boolean containsKey(String key) ;

    /**
     * Returns {@code true} if and only if this {@code CompositeData} instance contains an item
     * whose value is {@code value}.
     *
     * @param value the value to be tested.
     *
     * @return true if this {@code CompositeData} contains the value.
     */
    public boolean containsValue(Object value) ;

    /**
     * Returns an unmodifiable Collection view of the item values
     * contained in this {@code CompositeData} instance.
     * The returned collection's iterator will return the values
     * in the ascending lexicographic order of the corresponding
     * item names.
     *
     * @return the values.
     */
    public Collection<?> values() ;

    /**
     * Compares the specified <var>obj</var> parameter with this
     * {@code CompositeData} instance for equality.
     * <p>
     * Returns {@code true} if and only if all of the following statements are true:
     * <ul>
     * <li><var>obj</var> is non null,</li>
     * <li><var>obj</var> also implements the {@code CompositeData} interface,</li>
     * <li>their composite types are equal</li>
     * <li>their contents, i.e. (name, value) pairs are equal. If a value contained in
     * the content is an array, the value comparison is done as if by calling
     * the {@link java.util.Arrays#deepEquals(Object[], Object[]) deepEquals} method
     * for arrays of object reference types or the appropriate overloading of
     * {@code Arrays.equals(e1,e2)} for arrays of primitive types</li>
     * </ul>
     * <p>
     * This ensures that this {@code equals} method works properly for
     * <var>obj</var> parameters which are different implementations of the
     * {@code CompositeData} interface, with the restrictions mentioned in the
     * {@link java.util.Collection#equals(Object) equals}
     * method of the {@code java.util.Collection} interface.
     *
     * @param  obj  the object to be compared for equality with this
     * {@code CompositeData} instance.
     * @return  {@code true} if the specified object is equal to this
     * {@code CompositeData} instance.
     */
    public boolean equals(Object obj) ;

    /**
     * Returns the hash code value for this {@code CompositeData} instance.
     * <p>
     * The hash code of a {@code CompositeData} instance is the sum of the hash codes
     * of all elements of information used in {@code equals} comparisons
     * (ie: its <i>composite type</i> and all the item values).
     * <p>
     * This ensures that {@code t1.equals(t2)} implies that {@code t1.hashCode()==t2.hashCode()}
     * for any two {@code CompositeData} instances {@code t1} and {@code t2},
     * as required by the general contract of the method
     * {@link Object#hashCode() Object.hashCode()}.
     * <p>
     * Each item value's hash code is added to the returned hash code.
     * If an item value is an array,
     * its hash code is obtained as if by calling the
     * {@link java.util.Arrays#deepHashCode(Object[]) deepHashCode} method
     * for arrays of object reference types or the appropriate overloading
     * of {@code Arrays.hashCode(e)} for arrays of primitive types.
     *
     * @return the hash code value for this {@code CompositeData} instance
     */
    public int hashCode() ;

    /**
     * Returns a string representation of this {@code CompositeData} instance.
     * <p>
     * The string representation consists of the name of the implementing class,
     * the string representation of the composite type of this instance,
     * and the string representation of the contents
     * (ie list the itemName=itemValue mappings).
     *
     * @return  a string representation of this {@code CompositeData} instance
     */
    public String toString() ;

}