/*
* JBoss DNA (http://www.jboss.org/dna)
* See the COPYRIGHT.txt file distributed with this work for information
* regarding copyright ownership. Some portions may be licensed
* to Red Hat, Inc. under one or more contributor license agreements.
* See the AUTHORS.txt file in the distribution for a full listing of
* individual contributors.
*
* JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
* is licensed to you under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* JBoss DNA 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.dna.graph.request;
import java.util.LinkedList;
import java.util.List;
import org.jboss.dna.common.text.Inflector;
import org.jboss.dna.common.util.CheckArg;
import org.jboss.dna.common.util.HashCode;
import org.jboss.dna.graph.GraphI18n;
import org.jboss.dna.graph.Location;
import org.jboss.dna.graph.connector.RepositoryConnection;
import org.jboss.dna.graph.property.Path;
import org.jboss.dna.graph.property.Property;
/**
* Instruction to read a block of the children of a node, where the block is dictated by the {@link #startingAtIndex() starting
* index} and the {@link #count() maximum number of children} to include in the block. This command is useful when paging through
* a large number of children.
*
* @see ReadNextBlockOfChildrenRequest
*/
public class ReadBlockOfChildrenRequest extends CacheableRequest {
public static final int INDEX_NOT_USED = -1;
private static final long serialVersionUID = 1L;
private final Location of;
private final String workspaceName;
private final List<Location> children = new LinkedList<Location>();
private final int startingAtIndex;
private final int count;
private Location actualLocation;
/**
* Create a request to read a block of the children of a node at the supplied location. The block is defined by the starting
* index of the first child and the number of children to include. Note that this index is <i>not</i> the
* {@link Path.Segment#getIndex() same-name-sibiling index}, but rather is the index of the child as if the children were in
* an array.
*
* @param of the location of the node whose children are to be read
* @param workspaceName the name of the workspace containing the parent
* @param startingIndex the zero-based index of the first child to be included in the block
* @param count the maximum number of children that should be included in the block
* @throws IllegalArgumentException if the location or workspace name is null, if <code>startingIndex</code> is negative, or
* if <code>count</count> is less than 1.
*/
public ReadBlockOfChildrenRequest( Location of,
String workspaceName,
int startingIndex,
int count ) {
CheckArg.isNotNull(of, "of");
CheckArg.isNonNegative(startingIndex, "startingIndex");
CheckArg.isPositive(count, "count");
CheckArg.isNotNull(workspaceName, "workspaceName");
this.workspaceName = workspaceName;
this.of = of;
this.startingAtIndex = startingIndex;
this.count = count;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.request.Request#isReadOnly()
*/
@Override
public boolean isReadOnly() {
return true;
}
/**
* Get the location defining the node whose children are to be read.
*
* @return the location of the parent node; never null
*/
public Location of() {
return of;
}
/**
* Get the name of the workspace in which the parent and children exist.
*
* @return the name of the workspace; never null
*/
public String inWorkspace() {
return workspaceName;
}
/**
* Get the maximum number of children that may be returned in the block.
*
* @return the block's maximum count
* @see #startingAtIndex()
* @see #endingBefore()
*/
public int count() {
return this.count;
}
/**
* Get the starting index of the block, which is the index of the first child to include. This index corresponds to the index
* of all children in the list, not the {@link Path.Segment#getIndex() same-name-sibiling index}.
*
* @return the (zero-based) child index at which this block starts; never negative and always less than
* {@link #endingBefore()}
* @see #endingBefore()
* @see #count()
*/
public int startingAtIndex() {
return this.startingAtIndex;
}
/**
* Get the index past the last child that is to be included in the block. This index corresponds to the index of all children
* in the list, not the {@link Path.Segment#getIndex() same-name-sibiling index}.
*
* @return the index just past the last child included in the block; always positive and always greater than
* {@link #startingAtIndex()}.
* @see #startingAtIndex()
* @see #count()
*/
public int endingBefore() {
return this.startingAtIndex + this.count;
}
/**
* Get the children that were read from the {@link RepositoryConnection} after the request was processed. Each child is
* represented by a location.
*
* @return the children that were read; never null
*/
public List<Location> getChildren() {
return children;
}
/**
* Add to the list of children that has been read the supplied children with the given path and identification properties. The
* children are added in order.
*
* @param children the locations of the children that were read
* @throws IllegalArgumentException if the parameter is null
* @throws IllegalStateException if the request is frozen
* @see #addChild(Location)
* @see #addChild(Path, Property)
* @see #addChild(Path, Property, Property...)
*/
public void addChildren( Iterable<Location> children ) {
checkNotFrozen();
CheckArg.isNotNull(children, "children");
for (Location child : children) {
if (child != null) this.children.add(child);
}
}
/**
* Add to the list of children that has been read the child with the given path and identification properties. The children
* should be added in order.
*
* @param child the location of the child that was read
* @throws IllegalArgumentException if the location is null
* @throws IllegalStateException if the request is frozen
* @see #addChild(Path, Property)
* @see #addChild(Path, Property, Property...)
*/
public void addChild( Location child ) {
checkNotFrozen();
CheckArg.isNotNull(child, "child");
this.children.add(child);
}
/**
* Add to the list of children that has been read the child with the given path and identification properties. The children
* should be added in order.
*
* @param pathToChild the path of the child that was just read
* @param firstIdProperty the first identification property of the child that was just read
* @param remainingIdProperties the remaining identification properties of the child that was just read
* @throws IllegalArgumentException if the path or identification properties are null
* @throws IllegalStateException if the request is frozen
* @see #addChild(Location)
* @see #addChild(Path, Property)
*/
public void addChild( Path pathToChild,
Property firstIdProperty,
Property... remainingIdProperties ) {
checkNotFrozen();
Location child = Location.create(pathToChild, firstIdProperty, remainingIdProperties);
this.children.add(child);
}
/**
* Add to the list of children that has been read the child with the given path and identification property. The children
* should be added in order.
*
* @param pathToChild the path of the child that was just read
* @param idProperty the identification property of the child that was just read
* @throws IllegalArgumentException if the path or identification properties are null
* @throws IllegalStateException if the request is frozen
* @see #addChild(Location)
* @see #addChild(Path, Property, Property...)
*/
public void addChild( Path pathToChild,
Property idProperty ) {
checkNotFrozen();
Location child = Location.create(pathToChild, idProperty);
this.children.add(child);
}
/**
* Sets the actual and complete location of the node whose children have been read. This method must be called when processing
* the request, and the actual location must have a {@link Location#getPath() path}.
*
* @param actual the actual location of the node being read, or null if the {@link #of() current location} should be used
* @throws IllegalArgumentException if the actual location is not {@link Location#equals(Object) equal to} the {@link #of()
* current location}, or if the actual location does not have a path.
* @throws IllegalStateException if the request is frozen
*/
public void setActualLocationOfNode( Location actual ) {
checkNotFrozen();
if (!of.equals(actual)) { // not same if actual is null
throw new IllegalArgumentException(GraphI18n.actualLocationNotEqualToInputLocation.text(actual, of));
}
assert actual != null;
if (!actual.hasPath()) {
throw new IllegalArgumentException(GraphI18n.actualLocationMustHavePath.text(actual));
}
this.actualLocation = actual;
}
/**
* Get the actual location of the node whose children were read.
*
* @return the actual location, or null if the actual location was not set
*/
public Location getActualLocationOfNode() {
return actualLocation;
}
/**
* {@inheritDoc}
*
* @see org.jboss.dna.graph.request.Request#cancel()
*/
@Override
public void cancel() {
super.cancel();
this.actualLocation = null;
this.children.clear();
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
return HashCode.compute(of, workspaceName);
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals( Object obj ) {
if (obj == this) return true;
if (this.getClass().isInstance(obj)) {
ReadBlockOfChildrenRequest that = (ReadBlockOfChildrenRequest)obj;
if (!this.of().isSame(that.of())) return false;
if (this.startingAtIndex() != that.startingAtIndex()) return false;
if (this.count() != that.count()) return false;
if (!this.inWorkspace().equals(that.inWorkspace())) return false;
return true;
}
return false;
}
/**
* {@inheritDoc}
*
* @see java.lang.Object#toString()
*/
@Override
public String toString() {
Inflector inflector = Inflector.getInstance();
if (count() == 1) {
return "read " + inflector.ordinalize(startingAtIndex()) + " thru " + inflector.ordinalize(endingBefore() - 1)
+ " children of " + of() + " in the \"" + workspaceName + "\" workspace";
}
return "read " + inflector.ordinalize(startingAtIndex()) + " child of " + of() + " in the \"" + workspaceName
+ "\" workspace";
}
}