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package javax.management.openmbean;
// java import
//
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
// jmx import
//
The TabularType
class is the open type class whose instances describe the types of TabularData
values. Since: 1.5
/**
* The <code>TabularType</code> class is the <i> open type</i> class
* whose instances describe the types of {@link TabularData TabularData} values.
*
* @since 1.5
*/
public class TabularType extends OpenType<TabularData> {
/* Serial version */
static final long serialVersionUID = 6554071860220659261L;
@serial The composite type of rows
/**
* @serial The composite type of rows
*/
private CompositeType rowType;
@serial The items used to index each row element, kept in the order the user gave This is an unmodifiable ArrayList
/**
* @serial The items used to index each row element, kept in the order the user gave
* This is an unmodifiable {@link ArrayList}
*/
@SuppressWarnings("serial") // Conditionally serializable
private List<String> indexNames;
private transient Integer myHashCode = null; // As this instance is immutable, these two values
private transient String myToString = null; // need only be calculated once.
/* *** Constructor *** */
Constructs a TabularType
instance, checking for the validity of the given parameters.
The validity constraints are described below for each parameter.
The Java class name of tabular data values this tabular type represents (ie the class name returned by the getClassName
method) is set to the string value returned by TabularData.class.getName()
.
Params: - typeName – The name given to the tabular type this instance represents; cannot be a null or empty string.
- description – The human readable description of the tabular type this instance represents;
cannot be a null or empty string.
- rowType – The type of the row elements of tabular data values described by this tabular type instance;
cannot be null.
- indexNames – The names of the items the values of which are used to uniquely index each row element in the
tabular data values described by this tabular type instance;
cannot be null or empty. Each element should be an item name defined in rowType
(no null or empty string allowed).
It is important to note that the order of the item names in indexNames is used by the methods
get
and remove
of class TabularData
to match their array of values parameter to items.
Throws: - IllegalArgumentException – if rowType is null,
or indexNames is a null or empty array,
or an element in indexNames is a null or empty string,
or typeName or description is a null or empty string.
- OpenDataException – if an element's value of indexNames
is not an item name defined in rowType.
/**
* Constructs a <code>TabularType</code> instance, checking for the validity of the given parameters.
* The validity constraints are described below for each parameter.
* <p>
* The Java class name of tabular data values this tabular type represents
* (ie the class name returned by the {@link OpenType#getClassName() getClassName} method)
* is set to the string value returned by <code>TabularData.class.getName()</code>.
*
* @param typeName The name given to the tabular type this instance represents; cannot be a null or empty string.
* <br>
* @param description The human readable description of the tabular type this instance represents;
* cannot be a null or empty string.
* <br>
* @param rowType The type of the row elements of tabular data values described by this tabular type instance;
* cannot be null.
* <br>
* @param indexNames The names of the items the values of which are used to uniquely index each row element in the
* tabular data values described by this tabular type instance;
* cannot be null or empty. Each element should be an item name defined in <var>rowType</var>
* (no null or empty string allowed).
* It is important to note that the <b>order</b> of the item names in <var>indexNames</var>
* is used by the methods {@link TabularData#get(java.lang.Object[]) get} and
* {@link TabularData#remove(java.lang.Object[]) remove} of class
* <code>TabularData</code> to match their array of values parameter to items.
* <br>
* @throws IllegalArgumentException if <var>rowType</var> is null,
* or <var>indexNames</var> is a null or empty array,
* or an element in <var>indexNames</var> is a null or empty string,
* or <var>typeName</var> or <var>description</var> is a null or empty string.
* <br>
* @throws OpenDataException if an element's value of <var>indexNames</var>
* is not an item name defined in <var>rowType</var>.
*/
public TabularType(String typeName,
String description,
CompositeType rowType,
String[] indexNames) throws OpenDataException {
// Check and initialize state defined by parent.
//
super(TabularData.class.getName(), typeName, description, false);
// Check rowType is not null
//
if (rowType == null) {
throw new IllegalArgumentException("Argument rowType cannot be null.");
}
// Check indexNames is neither null nor empty and does not contain any null element or empty string
//
checkForNullElement(indexNames, "indexNames");
checkForEmptyString(indexNames, "indexNames");
// Check all indexNames values are valid item names for rowType
//
for (int i=0; i<indexNames.length; i++) {
if ( ! rowType.containsKey(indexNames[i]) ) {
throw new OpenDataException("Argument's element value indexNames["+ i +"]=\""+ indexNames[i] +
"\" is not a valid item name for rowType.");
}
}
// initialize rowType
//
this.rowType = rowType;
// initialize indexNames (copy content so that subsequent
// modifs to the array referenced by the indexNames parameter
// have no impact)
//
List<String> tmpList = new ArrayList<String>(indexNames.length + 1);
for (int i=0; i<indexNames.length; i++) {
tmpList.add(indexNames[i]);
}
this.indexNames = Collections.unmodifiableList(tmpList);
}
Checks that Object[] arg is neither null nor empty (ie length==0)
and that it does not contain any null element.
/**
* Checks that Object[] arg is neither null nor empty (ie length==0)
* and that it does not contain any null element.
*/
private static void checkForNullElement(Object[] arg, String argName) {
if ( (arg == null) || (arg.length == 0) ) {
throw new IllegalArgumentException("Argument "+ argName +"[] cannot be null or empty.");
}
for (int i=0; i<arg.length; i++) {
if (arg[i] == null) {
throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be null.");
}
}
}
Checks that String[] does not contain any empty (or blank characters only) string.
/**
* Checks that String[] does not contain any empty (or blank characters only) string.
*/
private static void checkForEmptyString(String[] arg, String argName) {
for (int i=0; i<arg.length; i++) {
if (arg[i].trim().isEmpty()) {
throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be an empty string.");
}
}
}
/* *** Tabular type specific information methods *** */
Returns the type of the row elements of tabular data values
described by this TabularType
instance.
Returns: the type of each row.
/**
* Returns the type of the row elements of tabular data values
* described by this <code>TabularType</code> instance.
*
* @return the type of each row.
*/
public CompositeType getRowType() {
return rowType;
}
Returns, in the same order as was given to this instance's
constructor, an unmodifiable List of the names of the items the
values of which are used to uniquely index each row element of
tabular data values described by this TabularType
instance.
Returns: a List of String representing the names of the index
items.
/**
* <p>Returns, in the same order as was given to this instance's
* constructor, an unmodifiable List of the names of the items the
* values of which are used to uniquely index each row element of
* tabular data values described by this <code>TabularType</code>
* instance.</p>
*
* @return a List of String representing the names of the index
* items.
*
*/
public List<String> getIndexNames() {
return indexNames;
}
Tests whether obj is a value which could be
described by this TabularType
instance.
If obj is null or is not an instance of
javax.management.openmbean.TabularData
,
isValue
returns false
.
If obj is an instance of
javax.management.openmbean.TabularData
, say
td
, the result is true if this TabularType
is assignable from
td.getTabularType()
, as defined in CompositeType.isValue
.
Params: - obj – the value whose open type is to be tested for
compatibility with this
TabularType
instance.
Returns: true
if obj is a value for this
tabular type, false
otherwise.
/**
* Tests whether <var>obj</var> is a value which could be
* described by this <code>TabularType</code> instance.
*
* <p>If <var>obj</var> is null or is not an instance of
* <code>javax.management.openmbean.TabularData</code>,
* <code>isValue</code> returns <code>false</code>.</p>
*
* <p>If <var>obj</var> is an instance of
* <code>javax.management.openmbean.TabularData</code>, say {@code
* td}, the result is true if this {@code TabularType} is
* <em>assignable from</em> {@link TabularData#getTabularType()
* td.getTabularType()}, as defined in {@link
* CompositeType#isValue CompositeType.isValue}.</p>
*
* @param obj the value whose open type is to be tested for
* compatibility with this <code>TabularType</code> instance.
*
* @return <code>true</code> if <var>obj</var> is a value for this
* tabular type, <code>false</code> otherwise.
*/
public boolean isValue(Object obj) {
// if obj is null or not a TabularData, return false
//
if (!(obj instanceof TabularData))
return false;
// if obj is not a TabularData, return false
//
TabularData value = (TabularData) obj;
TabularType valueType = value.getTabularType();
return isAssignableFrom(valueType);
}
@Override
boolean isAssignableFrom(OpenType<?> ot) {
if (!(ot instanceof TabularType))
return false;
TabularType tt = (TabularType) ot;
if (!getTypeName().equals(tt.getTypeName()) ||
!getIndexNames().equals(tt.getIndexNames()))
return false;
return getRowType().isAssignableFrom(tt.getRowType());
}
/* *** Methods overriden from class Object *** */
Compares the specified obj
parameter with this TabularType
instance for equality.
Two TabularType
instances are equal if and only if all of the following statements are true:
- their type names are equal
- their row types are equal
- they use the same index names, in the same order
Params: - obj – the object to be compared for equality with this
TabularType
instance;
if obj is null
, equals
returns false
.
Returns: true
if the specified object is equal to this TabularType
instance.
/**
* Compares the specified <code>obj</code> parameter with this <code>TabularType</code> instance for equality.
* <p>
* Two <code>TabularType</code> instances are equal if and only if all of the following statements are true:
* <ul>
* <li>their type names are equal</li>
* <li>their row types are equal</li>
* <li>they use the same index names, in the same order</li>
* </ul>
* <br>
* @param obj the object to be compared for equality with this <code>TabularType</code> instance;
* if <var>obj</var> is <code>null</code>, <code>equals</code> returns <code>false</code>.
*
* @return <code>true</code> if the specified object is equal to this <code>TabularType</code> instance.
*/
public boolean equals(Object obj) {
// if obj is null, return false
//
if (obj == null) {
return false;
}
// if obj is not a TabularType, return false
//
TabularType other;
try {
other = (TabularType) obj;
} catch (ClassCastException e) {
return false;
}
// Now, really test for equality between this TabularType instance and the other:
//
// their names should be equal
if ( ! this.getTypeName().equals(other.getTypeName()) ) {
return false;
}
// their row types should be equal
if ( ! this.rowType.equals(other.rowType) ) {
return false;
}
// their index names should be equal and in the same order (ensured by List.equals())
if ( ! this.indexNames.equals(other.indexNames) ) {
return false;
}
// All tests for equality were successfull
//
return true;
}
Returns the hash code value for this TabularType
instance.
The hash code of a TabularType
instance is the sum of the hash codes
of all elements of information used in equals
comparisons
(ie: name, row type, index names).
This ensures that t1.equals(t2)
implies that t1.hashCode()==t2.hashCode()
for any two TabularType
instances t1
and t2
, as required by the general contract of the method Object.hashCode()
.
As TabularType
instances are immutable, the hash code for this instance is calculated once,
on the first call to hashCode
, and then the same value is returned for subsequent calls.
Returns: the hash code value for this TabularType
instance
/**
* Returns the hash code value for this <code>TabularType</code> instance.
* <p>
* The hash code of a <code>TabularType</code> instance is the sum of the hash codes
* of all elements of information used in <code>equals</code> comparisons
* (ie: name, row type, index names).
* This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code>
* for any two <code>TabularType</code> instances <code>t1</code> and <code>t2</code>,
* as required by the general contract of the method
* {@link Object#hashCode() Object.hashCode()}.
* <p>
* As <code>TabularType</code> instances are immutable, the hash code for this instance is calculated once,
* on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
*
* @return the hash code value for this <code>TabularType</code> instance
*/
public int hashCode() {
// Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())
//
if (myHashCode == null) {
int value = 0;
value += this.getTypeName().hashCode();
value += this.rowType.hashCode();
for (String index : indexNames)
value += index.hashCode();
myHashCode = Integer.valueOf(value);
}
// return always the same hash code for this instance (immutable)
//
return myHashCode.intValue();
}
Returns a string representation of this TabularType
instance.
The string representation consists of the name of this class (ie javax.management.openmbean.TabularType
),
the type name for this instance, the row type string representation of this instance,
and the index names of this instance.
As TabularType
instances are immutable, the string representation for this instance is calculated once,
on the first call to toString
, and then the same value is returned for subsequent calls.
Returns: a string representation of this TabularType
instance
/**
* Returns a string representation of this <code>TabularType</code> instance.
* <p>
* The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularType</code>),
* the type name for this instance, the row type string representation of this instance,
* and the index names of this instance.
* <p>
* As <code>TabularType</code> instances are immutable, the string representation for this instance is calculated once,
* on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
*
* @return a string representation of this <code>TabularType</code> instance
*/
public String toString() {
// Calculate the string representation if it has not yet been done (ie 1st call to toString())
//
if (myToString == null) {
final StringBuilder result = new StringBuilder()
.append(this.getClass().getName())
.append("(name=")
.append(getTypeName())
.append(",rowType=")
.append(rowType.toString())
.append(",indexNames=(");
String sep = "";
for (String index : indexNames) {
result.append(sep).append(index);
sep = ",";
}
result.append("))");
myToString = result.toString();
}
// return always the same string representation for this instance (immutable)
//
return myToString;
}
}