adding support for filter operation

src/main/java/com/podio/item/ItemAPI.java

@@ -11,6 +11,7 @@
 import com.podio.filter.ExternalIdFilterBy;
 import com.podio.filter.FilterByValue;
 import com.podio.filter.SortBy;
+import com.podio.item.filter.ItemFilter;
 import com.sun.jersey.api.client.GenericType;
 import com.sun.jersey.api.client.WebResource;
 
@@ -266,6 +267,11 @@ public List<ItemRevision> getItemRevisions(int itemId) {
 				});
 	}
 
+	public ItemsResponse filterItems(int appId, ItemFilter filter) {
+		return getResourceFactory().getApiResource("/item/app/" + appId + "/filter/")
+				.entity(filter, MediaType.APPLICATION_JSON_TYPE).post(ItemsResponse.class);
+	}
+
 	/**
 	 * Returns the items on app matching the given filters.
 	 * 

src/main/java/com/podio/item/ItemBadge.java

@@ -153,6 +153,7 @@ public int getFiles() {
 		return files;
 	}
 
+	@JsonProperty("file_count")
 	public void setFiles(int files) {
 		this.files = files;
 	}

src/main/java/com/podio/item/filter/Filter.java

@@ -1,5 +1,20 @@
 package com.podio.item.filter;
 
-public class Filter {
+import org.codehaus.jackson.annotate.JsonProperty;
 
+public abstract class Filter<VALUES> {
+
+    private final String key;
+
+    Filter(String key) {
+        this.key = key;
+    }
+
+    @JsonProperty("values")
+    public abstract VALUES getValues();
+
+    @JsonProperty("key")
+    public String getKey() {
+        return key;
+    }
 }

src/main/java/com/podio/item/filter/FilterCreatedOn.java

@@ -0,0 +1,28 @@
+package com.podio.item.filter;
+
+import org.codehaus.jackson.annotate.JsonProperty;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+public class FilterCreatedOn extends Filter<FilterInterval> {
+
+    /** non-static to allow for multi threading */
+    private final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
+
+    private final FilterInterval values;
+
+    public FilterCreatedOn(Date from, Date to) {
+        super("created_on");
+        values = new FilterInterval();
+        values.setFrom(from != null ? DATE_FORMAT.format(from) : null);
+        values.setTo(to != null ? DATE_FORMAT.format(to) : null);
+    }
+
+    @Override
+    @JsonProperty("values")
+    public FilterInterval getValues() {
+        return values;
+    }
+}

src/main/java/com/podio/item/filter/FilterDateField.java

@@ -0,0 +1,25 @@
+package com.podio.item.filter;
+
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
+import java.util.Date;
+
+public class FilterDateField extends FilterFieldValue<FilterInterval> {
+
+    /** non-static to allow for multi threading */
+    private final DateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd");
+
+    private final FilterInterval values;
+
+    public FilterDateField(int fieldId, Date from, Date to) {
+        super(fieldId);
+        values = new FilterInterval();
+        values.setFrom(from != null ? DATE_FORMAT.format(from) : null);
+        values.setTo(to != null ? DATE_FORMAT.format(to) : null);
+    }
+
+    @Override
+    public FilterInterval getValues() {
+        return values;
+    }
+}

src/main/java/com/podio/item/filter/FilterFieldValue.java

@@ -0,0 +1,8 @@
+package com.podio.item.filter;
+
+public abstract class FilterFieldValue<VALUES> extends Filter<VALUES> {
+
+    public FilterFieldValue(int fieldId) {
+        super(String.valueOf(fieldId));
+    }
+}

src/main/java/com/podio/item/filter/FilterInterval.java

@@ -0,0 +1,26 @@
+package com.podio.item.filter;
+
+import org.codehaus.jackson.annotate.JsonProperty;
+
+public class FilterInterval {
+
+    private String from;
+    private String to;
+
+    @JsonProperty("from")
+    public String getFrom() {
+        return from;
+    }
+
+    public void setFrom(String from) {
+        this.from = from;
+    }
+    @JsonProperty("to")
+    public String getTo() {
+        return to;
+    }
+
+    public void setTo(String to) {
+        this.to = to;
+    }
+}

src/main/java/com/podio/item/filter/ItemFilter.java

@@ -0,0 +1,78 @@
+package com.podio.item.filter;
+
+import org.codehaus.jackson.annotate.JsonProperty;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ItemFilter {
+
+    private String sortBy;
+    private Boolean sortDesc;
+    private Integer limit;
+    private Integer offset;
+    private List<Filter> filters;
+
+    public ItemFilter() {
+        filters = new ArrayList<Filter>();
+    }
+
+    /**
+     * Creates a copy (actual filters are only shallow copy!)
+     * @param filter
+     */
+    public ItemFilter(ItemFilter filter) {
+        this();
+        sortBy = filter.getSortBy();
+        sortDesc = filter.getSortDesc();
+        limit = filter.getLimit();
+        offset = filter.getOffset();
+        filters = filter.getFilters();
+    }
+
+
+    @JsonProperty("sort_by")
+    public String getSortBy() {
+        return sortBy;
+    }
+
+    public void setSortBy(String sortBy) {
+        this.sortBy = sortBy;
+    }
+
+    @JsonProperty("sort_desc")
+    public Boolean getSortDesc() {
+        return sortDesc;
+    }
+
+    public void setSortDesc(Boolean sortDesc) {
+        this.sortDesc = sortDesc;
+    }
+
+    @JsonProperty("limit")
+    public Integer getLimit() {
+        return limit;
+    }
+
+    public void setLimit(Integer limit) {
+        this.limit = limit;
+    }
+
+    @JsonProperty("offset")
+    public Integer getOffset() {
+        return offset;
+    }
+
+    public void setOffset(Integer offset) {
+        this.offset = offset;
+    }
+
+    @JsonProperty("filters")
+    public List<Filter> getFilters() {
+        return filters;
+    }
+
+    public void setFilters(List<Filter> filters) {
+        this.filters = filters;
+    }
+}