plugins/org.eclipse.mat.api/src/org/eclipse/mat/internal/collectionextract/MapCollectionExtractorBase.java

/*******************************************************************************
 * Copyright (c) 2008, 2021 SAP AG, IBM Corporation and others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *    SAP AG - initial API and implementation
 *    IBM Corporation - enhancements and fixes
 *    James Livingston - expose collection utils as API
 *******************************************************************************/
package org.eclipse.mat.internal.collectionextract;

import java.util.Iterator;
import java.util.Map.Entry;

import org.eclipse.mat.SnapshotException;
import org.eclipse.mat.inspections.collectionextract.IMapExtractor;
import org.eclipse.mat.snapshot.ISnapshot;
import org.eclipse.mat.snapshot.model.IObject;
import org.eclipse.mat.snapshot.model.IObjectArray;

public abstract class MapCollectionExtractorBase implements IMapExtractor
{
    protected final String keyField;
    protected final String valueField;

    public MapCollectionExtractorBase(String keyField, String valueField)
    {
        this.keyField = keyField;
        this.valueField = valueField;
    }

    public boolean hasCapacity()
    {
        return hasExtractableArray();
    }

    public Integer getCapacity(IObject coll) throws SnapshotException
    {
        IObjectArray table = extractEntries(coll);
        return (table == null) ? null : table.getLength();
    }

    public Iterator<Entry<IObject, IObject>> extractMapEntries(IObject coll)
    {
        try
        {
            return new MapEntryIterator(coll.getSnapshot(), coll, extractEntryIds(coll));
        }
        catch (SnapshotException e)
        {
            throw new RuntimeException(e);
        }
    }

    private class MapEntryIterator implements Iterator<Entry<IObject, IObject>>
    {
        private final ISnapshot snapshot;
        private final int[] ids;
        private int idx;
        private IObject coll;

        public MapEntryIterator(ISnapshot snapshot, IObject coll, int[] ids)
        {
            this.snapshot = snapshot;
            this.ids = ids;
            this.idx = 0;
            this.coll = coll;
        }

        public boolean hasNext()
        {
            return idx < ids.length;
        }

        public Entry<IObject, IObject> next()
        {
            try
            {
                IObject obj = snapshot.getObject(ids[idx++]);
                return new EntryObject(obj, null, null) {
                    public IObject getKey()
                    {
                        return getEntryKey(obj);
                    }
                    public IObject getValue()
                    {
                        return getEntryValue(obj);
                    }
                };
            }
            catch (SnapshotException e)
            {
                throw new RuntimeException(e);
            }
        }

        public void remove()
        {
            throw new UnsupportedOperationException();
        }
    }

    protected IObject getEntryKey(IObject obj)
    {
        try
        {
            IObject ret = (IObject) obj.resolveValue(keyField);
            if (ret != null)
            {
                return ret;
            }
            else
            {
                return null;
            }
        }
        catch (SnapshotException e)
        {
            //throw new RuntimeException(e);
            return null;
        }
    }

    protected IObject getEntryValue(IObject obj)
    {
        try
        {
            return (IObject) obj.resolveValue(valueField);
        }
        catch (SnapshotException e)
        {
            //throw new RuntimeException(e);
            return null;
        }
    }
}