src/java.management/share/classes/javax/management/openmbean/TabularType.java
changeset 47216 71c04702a3d5
parent 25859 3317bb8137f4
child 52902 e3398b2e1ab0
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.management/share/classes/javax/management/openmbean/TabularType.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,380 @@
+/*
+ * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+
+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 <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
+     */
+    private CompositeType  rowType;
+
+    /**
+     * @serial The items used to index each row element, kept in the order the user gave
+     *         This is an unmodifiable {@link ArrayList}
+     */
+    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 <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>&nbsp;
+     * @param  description  The human readable description of the tabular type this instance represents;
+     *                      cannot be a null or empty string.
+     * <br>&nbsp;
+     * @param  rowType  The type of the row elements of tabular data values described by this tabular type instance;
+     *                  cannot be null.
+     * <br>&nbsp;
+     * @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>&nbsp;
+     * @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>&nbsp;
+     * @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.
+     */
+    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.
+     */
+    private static void checkForEmptyString(String[] arg, String argName) {
+        for (int i=0; i<arg.length; i++) {
+            if (arg[i].trim().equals("")) {
+                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 <code>TabularType</code> instance.
+     *
+     * @return the type of each row.
+     */
+    public CompositeType getRowType() {
+
+        return rowType;
+    }
+
+    /**
+     * <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 <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 <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>&nbsp;
+     * @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 <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 <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;
+    }
+
+}